WO2003011112A2 - System and method for determining reentrant ventricular tachycardia isthmus location and shape for catheter ablation - Google Patents
System and method for determining reentrant ventricular tachycardia isthmus location and shape for catheter ablation Download PDFInfo
- Publication number
- WO2003011112A2 WO2003011112A2 PCT/US2002/024130 US0224130W WO03011112A2 WO 2003011112 A2 WO2003011112 A2 WO 2003011112A2 US 0224130 W US0224130 W US 0224130W WO 03011112 A2 WO03011112 A2 WO 03011112A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- activation
- isthmus
- location
- reentry
- electrogram
- Prior art date
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/316—Modalities, i.e. specific diagnostic methods
- A61B5/318—Heart-related electrical modalities, e.g. electrocardiography [ECG]
- A61B5/339—Displays specially adapted therefor
- A61B5/341—Vectorcardiography [VCG]
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
- A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
- A61B18/14—Probes or electrodes therefor
- A61B18/1492—Probes or electrodes therefor having a flexible, catheter-like structure, e.g. for heart ablation
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/316—Modalities, i.e. specific diagnostic methods
- A61B5/318—Heart-related electrical modalities, e.g. electrocardiography [ECG]
- A61B5/346—Analysis of electrocardiograms
- A61B5/349—Detecting specific parameters of the electrocardiograph cycle
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00053—Mechanical features of the instrument of device
- A61B2018/00214—Expandable means emitting energy, e.g. by elements carried thereon
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
- A61B2018/00345—Vascular system
- A61B2018/00351—Heart
- A61B2018/00357—Endocardium
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00636—Sensing and controlling the application of energy
- A61B2018/00773—Sensed parameters
- A61B2018/00839—Bioelectrical parameters, e.g. ECG, EEG
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00636—Sensing and controlling the application of energy
- A61B2018/00898—Alarms or notifications created in response to an abnormal condition
-
- G—PHYSICS
- G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
- G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
- G16H50/00—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics
- G16H50/50—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics for simulation or modelling of medical disorders
Definitions
- the invention of the present disclosure was made from Government support under Grant HL-31393 and Project Grant HL-30557 from the Heart, Lung and Blood Institutes, National Institutes of Health, a Research Grant from the Whitaker Foundation, and the American Heart Association Established Investigator Award. Accordingly, the U.S. Government has certain rights to this invention.
- the isthmus tends to form along an axis from the area of last to first activity during sinus rhythm. It was hypothesized that this phenomenon could be quantified to predict reentry and the isthmus location.
- An in situ canine model of reentrant ventricular tachycardia occurring in the epicardial border zone was used in 54 experiments (25 canine hearts in which primarily long monomorphic runs of figure-8 reentry was inducible, 11 with short monomorphic or polymorphic runs, and 18 lacking inducible reentry) . From the sinus rhythm activation map for each experiment, the linear regression coefficient and slope was calculated for the activation times along each of 8 rays extending from the area of last-activation.
- the slope of the regression line for the ray with greatest regression coefficient (called the primary axis) was used to predict whether or not reentry would be inducible (correct prediction in 48/54 experiments) .
- isthmus location and shape were then estimated based on site-to-site differences in sinus rhythm electrogram duration.
- estimated isthmus location and shape partially overlapped the actual isthmus (mean overlap of 71.3% and 43.6%, respectively).
- a linear ablation lesion positioned across the estimated isthmus would have spanned 78.2% of the actual isthmus width. Parameters of sinus rhythm activation provide key information for prediction of reentry inducibility, and isthmus location and shape.
- ventricular tachycardia the heart beats rapidly which can be debilitating to the patient and cause such things as tiredness and even syncope (i.e. fainting).
- This clinical problem usually follows a myocardial infarction (heart attack) and is caused by abnormal electrical conduction in the heart because the cells become damaged during the infarct .
- conduction is slow and abnormal, a process called reentry can occur in which the propagating electrical wavefront travels in a circle, or double loop, and reenters the area where it had previously traveled. This propagation around the loop(s) occurs very rapidly, and a heartbeat occurs once each time the propagating wavefront traverses around the loop or loops .
- the heart muscle Since the condition is abnormal, the heart muscle does not contract as it should, so that the strength of the pumping action is reduced, and the rapidity of the heartbeat causes the heart chambers to not fill with blood completely. Therefore, because of both the poor filling action and the poor pumping action, there is less blood delivered to the tissues. This causes the maladies that the patient experiences .
- radio-frequency catheter ablation which does not require surgery and is permanent.
- a catheter is inserted through an artery of the patient and is positioned in the heart chamber.
- radio- frequency energy is delivered from the tip of the catheter to the heart tissue, thereby blocking conduction at the place of delivery of the energy, which is called the target site on the heart.
- energy is delivered to the location between the double loop where the electrical wavefront propagates. This is called the best, or optimal target site.
- it is sometimes difficult to locate the best target site, and also the precise surface area to which energy should be delivered is often unknown and presently must be done by trial and error.
- the present disclosure describes a system and method for determining the shape and location of the target site, which is called the reentry isthmus.
- U.S. Patent No. 6,236,883 to Ciaccio et al describes a method to find the isthmus based on signals acquired while the heart was undergoing ventricular tachycardia.
- the reentry isthmus may be localized and its shape may be estimated based on sinus-rhythm signals from the heart surface. Sinus-rhythm is the normal rhythm of the heart. Therefore, based on this methodology there may no longer be a need to induce ventricular tachycardia in the patient' s heart during clinical EP study.
- the method of the present disclosure provides the clinician with a target area to ablate the heart to stop reentrant ventricular tachycardia from recurring. Accuracy is important so that only those portions of the heart at which ablation is needed are actually ablated. Ablating other areas can increase the chance of patient morbidity, by damaging regions of the heart unnecessarily. Also, there is less chance that the patient will be required to have a repeat visit, which will reduce cost of the total procedure and reduce discomfort to the patient. Rapidity is important to reduce the amount of fluoroscopy time and therefore reduce the radiation exposure to the patient, as well as cost due to the reduction in time for the procedure, and patient discomfort.
- the method of the present disclosure is also an advance over previous methods because there may be no need to acquire many signals directly from the heart surface which is difficult and time consuming, for the procedure. Instead, only the electrocardiogram (ECG) signal may be needed during tachycardia. This ECG signal may be obtained during the EP study, or even via a Holter Monitor when the patient is ambulatory and the heart undergoes an episode of tachycardia. Therefore, the method of the present disclosure may greatly improve the accuracy of targeting the best ablation site to stop reentrant ventricular tachycardia even when tachycardia cannot be induced or is hemodynamically stable, both of which occur in a significant number of patients.
- ECG electrocardiogram
- Treatment of reentrant ventricular tachycardia by catheter ablation methods is hampered by the difficulty in localizing the circuit, particularly when the circuit structure is complex, the tachycardia is short-lived, or when reentry is not inducible during electrophysiologic study [1] . If measurements of sinus rhythm activation could be used to accurately localize reentry circuit features, it could potentially greatly improve the cure rate under these circumstances. A number of clinical and experimental studies to determine the usefulness of sinus rhythm parameters for targeting reentry circuits have been reported. The time of latest depolarization during sinus rhythm has been partially correlated to the location of the reentry isthmus; however, the relationship is inexact [2-3] .
- both normal and abnormal electrograms are present [2-5] ; however, these abnormal electrograms can be present both within and away from the reentry circuit location and are therefore not a specific predictor of its position in the border zone. Therefore, methods for detection and measurement of abnormal sinus rhythm activation characteristics are not presently sufficient for targeting reentry circuits for catheter ablation, although presence of abnormality suggests the proximity of arrhythmogenic substrate.
- the area where the isthmus forms has at least two conspicuous substrate properties: 1) it is the thinnest surviving cell layer of any area of the border zone [6-7], and 2) there is disarray of gap-junctional intercellular connections which extends the full thickness from the infarct to the surface of the heart [8] . Since these substrate properties persist regardless of rhythm type, they may affect electrical conduction at the isthmus area during sinus rhythm. The hypothesis that these phenomena could be quantified and used to predict reentry inducibility, and isthmus location and shape, when it occurs, was tested in this study.
- This disclosure provides a method for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm, comprising the steps of: a) receiving electrogram signals from the heart during sinus rhythm via electrodes; b) creating a map based on the received electrogram signals; c) determining, based on the map, a location of the reentrant circuit isthmus in the heart; and d) displaying the location of the reentrant circuit isthmus.
- This disclosure provides a method for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm, comprising the steps of: a) receiving electrogram signals from the heart during sinus rhythm via electrodes; b) creating a map based on the received electrogram signals; c) finding a center reference activation location on the map; d) defining measurement vectors originating from the center reference activation location; e) selecting from the measurement vectors a primary vector indicating a location of the reentrant circuit isthmus in the heart; and f) displaying the location of the reentrant circuit isthmus.
- This disclosure provides a system for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm, comprising: a) an interface for receiving electrogram signals from the heart during sinus rhythm via electrodes; b) processing means for creating a map based on the received electrogram signals, and determining, based on the map, a location of the reentrant circuit isthmus in the heart; c) a display adapted to display the location of the reentrant circuit isthmus.
- This disclosure provides a system for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm, comprising: a) receiving means for receiving electrogram signals from the heart during sinus rhythm via electrodes; b) storage means for storing electrogram data corresponding to the electrogram signals received by the receiving means; c) processing means for retrieving the electrogram data, creating a map based on the electrogram signals, finding a center reference activation location on the map, defining measurement vectors originating from the center reference activation location, selecting from the measurement vectors a primary axis vector indicating a location of the reentrant circuit isthmus in the heart, finding threshold points of the electrogram signals on the map, and connecting the threshold points to form a polygon indicating a shape of the reentrant circuit isthmus in the heart; and d) a display for displaying one of the location and shape of the reentrant circuit isthmus.
- FIGS. 1A-1D are maps of a heart experiencing ventricular tachycardia in which long-runs of monomorphic reentry were inducible by center pacing.
- FIGS. 1A-1C are activation maps of the reentrant circuit. At the four margins of the map are indicated their respective locations on the heart: the left anterior descending coronary (LAD) , the base, lateral left ventricle (LAT) , and apex. The small numbers in boxes are activation times at each of the recording sites. Isochrones are labeled with larger numbers in boxes. The shaded area represents the place where the double loop merges during reentry (called the central common pathway or reentry isthmus) .
- FIG. 1A contains ray numbers as well as the results of linear regression analysis along each ray.
- the columns of the table show the slope of the regression line, termed the activation gradient (AG) , and linear regression coefficient (r 2 ) values, termed the activation uniformity (AU) .
- Thick black lines designate regions of conduction block. Arrows show the direction of wavefront propagation.
- FIG. ID shows an electrogram duration map for the sinus-rhythm cycle of FIG. 1A.
- the locations of the reentry arcs of block from the activation map of FIG. IC are shown overlapped as thick black lines. Between the arcs of block is the actual location of the reentry isthmus.
- the estimated isthmus location determined by activation and electrogram duration analysis, is inscribed by the small circles on the map. The estimated area approximately overlaps the shape of the actual reentry isthmus.
- FIGS. 2A-2D are activation and electrogram duration maps for an experiment in which short-runs of monomorphic reentry were inducible by pacing from the basal margin.
- This figure shows that as for cases in which long-runs (greater than 10 heartbeats) are recorded, even when ventricular tachycardia is of very short duration (less than 10 heartbeats) it is possible to estimate the reentry isthmus location using sinus-rhythm activation and electrogram duration mapping.
- the actual reentry isthmus location is the area between the solid lines of duration map FIG. 2D for one of the cardiac cycles. For another of the cardiac-cycles, the shape changed slightly as shown by the dotted lines.
- the estimated reentry isthmus for this case of ventricular tachycardia is denoted by the area inscribed by the small circles, and may approximately overlap the actual reentry isthmus.
- FIGS. 3A and 3B show a database, represented as a scatter plot, and one and two-dimensional boundary lines for classification of the primary vector parameters of activation gradient (AG) and activation uniformity (AU) according to one embodiment of the present disclosure.
- the dotted line shows the best boundary-line to classify those cases in which reentry may occur versus those cases in which reentry may not occur based on the sinus-rhythm activation gradient parameter.
- the boundary line separates most of the cases in which long-runs of monomorphic reentry could be induced (solid circles) to the left side of the plot, and most of the cases in which reentry was not inducible (open circles) to the right side of the plot, in FIGS.
- FIG. 3A the dashed line denotes the best two-dimensional boundary to separate cases in which reentrant ventricular tachycardia would versus would not be inducible based on the sinus-rhythm activation gradient and uniformity.
- This two-dimensional classification boundary improved classification by correctly adding two more open circles (no reentry occurred) to the right side of the boundary- line.
- FIG. 3B the same procedure is used, with the same result, except that the parameters were the mean electrogram duration and the activation gradient.
- FIGS. 4A-4Y are estimated isthmus parameters - experiments with long-runs of reentry.
- the actual reentry isthmus is the area between the arcs of block denoted by thick curvy black lines.
- the estimated reentry isthmus derived from electrogram duration and activation analysis is denoted by the cross-hatched area.
- the estimated and actual reentry isthmuses often coincide.
- the location and direction of the primary axis determined from activation mapping is denoted by the arrow in FIGS. 4A-4Y, and in most cases it approximately aligns with the long-axis (i.e., entrance to exit direction) of the reentry isthmus.
- the dashed line denotes the estimated best ablation line.
- FIGS. 5A-5K are estimated isthmus parameters - experiments with short-runs of reentry.
- FIGS. 5A-5E are taken during polymorphic tachycardia where the electrocardiogram or ECG is irregular in period and/or shape of the signal.
- FIGS. 5F-5K were taken during monomorphic tachycardia where the electrocardiogram or ECG is regular in period and in shape of the signal.
- FIGS. 5A-5K are the same as for FIGS. 4A-4Y except that these cases included only short-runs, for example, less than 10 heartbeats of ventricular tachycardia.
- FIG. 6 is a regression line diagram according to one embodiment of the present disclosure.
- FIG. 7 shows a flow chart of a method, according to an embodiment of the present disclosure, for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm.
- FIGS. 8A-8D show maps according to one embodiment of the present disclosure.
- the activation maps of the endocardial surface during ventricular tachycardia are shown for four different patients.
- the thick black curvy lines denote arcs of conduction block, and the thinner curvy lines are isochrones of equal activation time, which are labeled.
- FIG. 8A patient 1
- the wavefront proceeds between arcs of block at two areas. At the left of the map it crosses the area between the arcs of block at a time of approximately 100 milliseconds, and proceeds upward.
- the activation wavefront crosses the area between the arcs of block at a time of approximately 0 milliseconds and proceeds downward.
- FIGS. 9A-9D show maps according to one embodiment of the present disclosure. These are an example of how sinus- rhyth electrogram analyses can be used to ascertain the position where the reentrant circuit isthmus will form in the infarct border zone, and the best line to ablate to stop ventricular tachycardia.
- FIG. 9A shows the sinus- rhythm activation map. The area of last activation is marked and proceeding from it are eight measurements vectors. The linear regression resulting from each measurement vector is shown in the accompanying table. The vector with greatest activation uniformity and low activation gradient is ray 2 and it is in-spec. Hence ray 2 is the primary axis.
- FIG. 9B shows the electrogram duration map.
- points with differences in sinus-rhythm electrogram duration between recording sites of, for example, >15 milliseconds are denoted by circles. These circles on the computerized map grid are connected to for the polygonal surface that is the estimated location and shape of the reentrant circuit isthmus.
- the estimated best line to ablate which bisects the estimated isthmus into regions with equal surface area, is denoted by the dashed line and it is perpendicular to the primary axis (measurement vector 2 in FIG. 9A) .
- FIG. 9B examples of electrograms in regions with differing sinus- rhythm electrogram duration are shown. When electrogram duration is long, the deflections occur for a longer time during each cardiac-cycle.
- FIG. 9C shows the activation map during pacing. Note that the areas of last activation during pacing coincide with region with long sinus-rhythm electrogram duration.
- FIG. 9D shows the activation map during tachycardia. There is a reentrant circuit, and it occurs precisely as predicted from the sinus-rhythm electrogram analyses. Ablating along the line denoted in FIG. 9B would cause reentrant ventricular tachycardia to cease because the electrical impulse would be blocked as it traversed the actual isthmus area (FIG. 9D) .
- FIG. 10 shows estimated isthmuses according to one embodiment of the present disclosure.
- FIG. 10 shows the estimated isthmuses from sinus-rhythm electrogram analyses (dashed lines) and best lines to ablate (dotted lines), and the actual isthmuses determined from activation mapping during ventricular tachycardia (gray areas bordered by thick black curvy lines which denote locations of the actual arcs of conduction block) , for the 11 patients of the clinical study.
- the arrows denote the location and direction of the primary axis. In each case, there is agreement between the estimated and actual isthmus of the reentrant circuit.
- ablating along the estimated best line would cause the electrical impulse to be blocked within the actual reentrant circuit isthmus; hence reentrant ventricular tachycardia would cease.
- the best estimated ablation line ablates little more of the heart than is necessary, hence minimizing the chance of patient morbidity as a result of the ablation procedure.
- FIGS. 11A-11F show maps according to one embodiment of the present disclosure. These figures show an example of sinus- rhythm electrogram analyses as well as PLATM.
- FIG. 12 shows a table of Patient Clinical Data.
- the patient nu ber, sex, infarct location, time from myocardial infarct to EP study, drug therapy, and VT cycle length at onset are given.
- FIG. 13 shows a diagram of a system according to an embodiment of the present disclosure.
- FIG. 14A shows a flow chart of a method, according to an embodiment of the present disclosure, for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm.
- FIG. 14B shows a flow chart of a method for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm, according to another embodiment of the present disclosure.
- FIG. 15A shows a flow chart of a method for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm, according to another embodiment of the present disclosure.
- FIG. 15B shows a flow chart of a method for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm, according to another embodiment of the present disclosure.
- FIG. 16A shows a high-level block diagram of a system, according to an embodiment of the present disclosure, for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm.
- FIG. 16B shows a high-level block diagram of a system for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm, according to another embodiment of the present disclosure.
- FIGS. 17A-17E are maps used for skeletonization procedures.
- FIG. 17A shows a reentry activation map.
- FIG. 17B shows a skeletonized reentry map.
- FIG. 17C shows a sinus-rhythm pace map.
- FIG. 17D shows a sinus-rhythm electrogram duration map. Locations of recording sites are shown by small numbers that indicate activation time (FIG. 17C) , and anatomic landmarks are labeled (FIG. 17A) .
- FIGS. 18A-18T show summaries of skeletonized geometric variables for 20 canine experiments (isthmus length, width, narrowest width, angle, and XY location in infarct border zone are shown in each figure) . Narrowest width is drawn at isthmus center for simplicity.
- FIG. 19 shows mean skeletonized reentry circuit parameters from measurements of all experiments. LAT indicates lateral.
- FIG. 20 shows a table of significant correlation relationships between skeletonized variables at the onset of stable tachycardia cycle length.
- FIGS. 21A-21E show actual (black) versus estimated (gray) reentry circuit arcs of block for 5 test-set experiments. Actual reentry activation isochrones and tachycardia cycle length measured from R-R interval are also shown in each figure.
- FIGS. 22A-22I show activation and electrogram duration maps for an experiment in which long runs of monomorphic reentry were inducible by premature stimulation from the base .
- FIGS. 23A-23Y show comparisons of longest estimated (blue) versus actual (black) arcs of conduction block and breakthrough point locations for premature excitation cycles leading to reentry in experiments with inducible tachycardia. Times in milliseconds at lower left of each figure give sinus rhythm cycle length (above) and S2 coupling interval (below).
- FIGS. 21A-21J correspond to 196 bipolar electrode recording array
- FIGS. 21K-21Y correspond to 312 bipolar electrode recording array.
- FIGS. 24A-24C are scatter plots of electrogram parameters used for clustering and classification based upon whether or not reentrant ventricular tachycardia would be expected to occur in the infarct border zone.
- Lines show linear discriminate functions for best separation of experiments into those with versus without inducible reentry (solid and open circles, respectively) .
- Solid lines show best two- dimensional linear discriminant function.
- Dashed lines show best one-dimensional linear discriminate function. Only relationships with >80% accuracy are shown.
- FIG. 24A shows mean difference in activation time across the longest estimated unidirectional arc versus its length.
- FIG. 24B shows mean difference in activation time versus mean electrogram duration in the border zone.
- FIG. 24C shows difference in activation time at proximal versus distal edge of the breakthrough point versus time from S2 stimulus to proximal edge of breakthrough point.
- FIG. 25 shows quantitative parameters of premature excitation.
- FIG. 26 shows significant regression relationships of premature excitation parameters .
- FIGS. 27A-27F show activation and electrogram duration maps which illustrate a method, according to one embodiment, for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm.
- FIGS. 28A-28I show sinus rhythm electrogram duration maps for nine experiments in which multiple reentrant circuit morphologies occurred.
- FIGS. 29A-29I are maps which show locations of the actual arcs of conduction block during reentry, versus the predicted location of each reentrant circuit isthmus.
- This disclosure provides methods for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm.
- the method comprises the steps of: a) receiving electrogram signals from the heart during sinus rhythm via electrodes (step S141) ; b) creating a map based on the received electrogram signals (step S142) ; c) determining, based on the map, a location of the reentrant circuit isthmus in the heart (step S143) ; and d) displaying the location of the reentrant circuit isthmus (step S144) .
- step b) includes arranging activation times of the received electrogram signals based on a position of the respective electrodes. In one embodiment of the above method, the activation times are measured from a predetermined start time until reception of a predetermined electrogram signal.
- the map includes isochrones for identifying electrogram signals having activation times within a predetermined range.
- step c) includes finding a center reference activation location on the map by averaging an electrode coordinate position of a predetermined number of electrogram signals selected based on an activation time.
- step c) includes defining measurement vectors originating from the center reference activation location and extending outward on the map, the measurement vectors used to designate the electrodes located along the measurement vectors.
- the electrodes assigned to a measurement vector are chosen according to a distance from the measurement vector. In one embodiment of the above method, the electrodes assigned to a measurement vector are a subset of the electrodes chosen according to a distance from the measurement vector.
- step c) includes selecting from the measurement vectors a primary axis vector having one of an activation gradient value within a predetermined range and a highest activation uniformity value within a predetermined range and where the primary axis vector indicates a location of the reentrant circuit isthmus .
- step (c) includes selecting from the measurement vectors a primary axis vector having one of a mean electrogram activation duration within a predetermined range, an activation gradient value within a predetermined range and a highest activation uniformity value within a predetermine range and where the primary axis vector indicates the location of the reentrant circuit isthmus .
- the activation uniformity value is a coefficient of linear regression. In one embodiment of the above method, the activation uniformity value is a coefficient of non-linear regression. In one embodiment of the above method, the activation uniformity value is a variance in activation times along a selected measurement vector. In one embodiment of the above method, the activation uniformity value is a measure of variability along a selected measurement vector.
- the activation gradient value is a slope of a linear regression line.
- the activation gradient value is a slope of a non-linear regression line. In one embodiment of the above method, the activation gradient value is a mean absolute difference in activation times along a selected measurement vector. In one embodiment of the above method, the activation gradient value is a difference along the measurement vector.
- step c) includes, when a primary axis vector is not found, finding an alternate center reference activation location on the map by averaging an electrode coordinate position of a predetermined number of electrogram signals having an alternate characteristic, defining measurement vectors originating from the alternate center reference activation location and extending outward on the map, the measurement vectors used to designate the electrodes located along the vectors, and selecting from the measurement vectors a primary axis vector having one of an activation gradient value within a predetermined range and a highest activation uniformity value within a predetermined range.
- step d) includes when a primary axis vector is not found, selecting from the measurement vectors a primary axis vector having one of an activation uniformity value within a predetermined range and a highest gradient value within a predetermined range.
- the above method further comprises the steps of: e) determining, based on the map, a shape of the reentrant circuit isthmus in the heart (step S145) ; and f) displaying the shape of the reentrant circuit isthmus (step S146) .
- step b) includes generating duration values representing a time difference between a starting point and a stopping point in the electrogram signals.
- the one of the starting point and stopping point is computed to be when an amplitude of the electrogram signal is within a predetermined amount of an amplitude of the electrogram signal .
- step e) includes finding threshold points in which the difference in electrogram duration values between adjacent sites is greater than a predetermined time interval.
- step e) includes connecting the threshold points to form a polygon encompassing the center reference activation location.
- step e) includes connecting the threshold points to form a polygon encompassing the center reference activation location and a predetermined portion of the primary axis vector and indicating a shape of the reentrant circuit isthmus in the heart .
- the above method further comprises the steps of: g) determining an ablation line to ablate the heart based on the location of the reentrant circuit isthmus (step S147); and h) displaying the ablation line (step S148) .
- step g) includes drawing the ablation line on the map bisecting the polygon and at a predetermined angle with respect to the primary axis vector.
- the ablation line traverses the polygon plus a predetermined distance.
- This disclosure provides another method for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm (FIG. 15A) , comprising the steps of: a) receiving electrogram signals from the heart during sinus rhythm via electrodes (step S151) ; b) creating a map based on the received electrogram signals (step S151)
- step S154 selecting from the measurement vectors a primary vector indicating a location of the reentrant circuit isthmus in the heart (step S155) ; and f) displaying the location of the reentrant circuit isthmus (step S156) .
- the above method further comprises the steps of: g) finding threshold points of the electrogram signals on the map (step S157); h) connecting the threshold points to form a polygon indicating a shape of the reentrant circuit isthmus in the heart (step S158) ; and i) displaying the shape of the reentrant circuit isthmus (step S159) .
- the above method further comprises the steps of: j) finding an ablation line based on the polygon (step S160) ; and k) displaying the ablation line (step S161) .
- the primary axis vector may have a mean activation duration in a predetermined range.
- a method for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm comprises determining a late-activation location during sinus rhythm, then determining the areas of short electrogram duration which are connected to this region, and determining the curved vector along each tract of short electrogram duration which has a uniform and slow sinus rhythm activation gradient.
- FIGS. 27A-27F illustrate the method.
- the sinus rhythm activation time map is shown in FIG. 27A and the sinus rhythm activation duration map, measured from the same cardiac cycle at the beginning of a selected experiment, is shown in FIG. 27B. Isochrones of like activation time are drawn on the activation time map at 10ms intervals (FIG. 27A) .
- FIG. 27A Three short arcs of conduction block, denoted by thick curved black lines, occurred during sinus rhythm.
- activation duration is short and using an activation duration of 30ms as a threshold, extends in three tracts away from the center point (FIG. 27B) .
- the locations of these tracts of short sinus rhythm activation duration are superimposed on the activation times map as a shaded region (FIG. 27A) .
- curved vectors are drawn where the sinus rhythm activation time gradient was most uniform and steep with the minimum thresholds as given above (colored red, blue, and green) .
- FIG. 27C premature stimulation from the basal margin of the grid that led to reentrant tachycardia is shown.
- FIG. 27A premature excitation time gradient
- FIG. 27B premature excitation duration
- the wave-front first proceeds along a tract of short activation duration as denoted by the gray shaded area (isochrones 20-80ms near the basal margin) , and along the LAD margin.
- the distinct wave-fronts coalesce near the apical margin and then propagate as a coherent wavefront along another of the tracts of short electrogram duration. Breakthrough occurs where activation duration is very short and the location is denoted by the blue arrow. This premature excitation cycle was followed by reentrant tachycardia of the morphologic type shown in FIG. 27D.
- the estimated arcs of block for this morphology are denoted by thick blue lines, and they follow the tract of short sinus rhythm activation duration that leads toward the LAD-basal margin of the mapping grid.
- the actual isthmus location resides along a tract of short sinus rhythm activation duration, and the wave-front tends to propagate along tracts of short activation duration for some distance preceding the entrance to the isthmuses and following exit from the isthmus locations.
- FIGS. 28A-28I show the sinus rhythm electrogram duration maps for nine experiments in which multiple reentrant circuit morphologies occurred. Shown are the vectors of uniform, shape sinus rhythm activation gradient, and the locations of the estimated arcs of conduction block during reentry at the edges of the tracts of short activation duration.
- FIG. 28C depicts the experiment of FIGS. 27A-27F in which three reentrant circuit morphologies occurred.
- the configuration for the experiment of FIG. 28D suggests that a third morphology might have been inducible with the exit pointing toward the apical margin. However, no vector with uniform, steep sinus rhythm activation gradient within the minimum thresholds as described in the Methods could be drawn along that tract of short activation duration.
- FIGS. 28A-28I show the sinus rhythm electrogram duration maps for nine experiments in which multiple reentrant circuit morphologies occurred. Shown are the vectors of uniform, shape sinus rhythm activation gradient, and the locations of the estimated arcs of conduction block during
- FIGS. 29A-29I show the locations of the actual arcs of conduction block during reentry, versus the predicted location of each reentrant circuit isthmus.
- the estimate in red corresponds to the actual arcs of block shown in black.
- the estimate in blue corresponds to the actual arcs of block shown in medium gray.
- the estimate in green (FIG. 29C only) corresponds to the actual arcs of block shown in light gray.
- violet color FIGS. 29A, 29C, 29D, 29F, 29H and 291
- brown color FIG. 29C
- This disclosure also provides a system for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm.
- the system comprises: an interface 165 for receiving electrogram signals from the heart during sinus rhythm via electrodes; processing means 166 for creating a map based on the received electrogram signals, and determining, based on the map, a location of the reentrant circuit isthmus in the heart; and a display 167 adapted to display the location of the reentrant circuit isthmus.
- the system comprises: receiving means 171 for receiving electrogram signals from the heart during sinus rhythm via electrodes; processing means 173 for creating a map based on the electrogram signals, finding a center reference activation location on the map, defining measurement vectors originating from the center reference activation location, selecting from the measurement vectors a primary axis vector indicating a location of the reentrant circuit isthmus in the heart, finding threshold points of the electrogram signals on the map, and connecting the threshold points to form a polygon indicating a shape of the reentrant circuit isthmus in the heart; and a display 174 for displaying one of the location and shape of the reentrant circuit isthmus.
- the system may optionally include storage means 172 for storing electrogram data corresponding to the electrogram signals received by the receiving means, and the processing means 173 retrieves and processes the electrogram data from the storage means 172.
- storage means 172 for storing electrogram data corresponding to the electrogram signals received by the receiving means, and the processing means 173 retrieves and processes the electrogram data from the storage means 172.
- the interface, receiving means, processing means display and storage means are, respectively, described in more detail below.
- the method of the present disclosure is used to target ablation sites on the surface of the heart to stop reentrant ventricular tachycardia from occurring. It may be used to target sites on either the endocardial or the epicardial surface of the heart.
- One embodiment of the present disclosure involves using signals acquired during sinus-rhythm, where sinus rhythm is the normal rhythm of the heart. These signals may be acquired during clinical electrophysiologic EP study with special equipment designed for this purpose.
- Several types of catheters are available for this purpose when the reentrant ventricular tachycardia is believed to be endocardial in origin. When reentrant ventricular tachycardia is believed to be epicardial in origin, open chest surgery or other procedures may be required to obtain signals and map conduction on the surface. The type of catheter may influence the data acquisition method.
- the probe does not contact the heart surface, signals may be acquired and by a mathematical inverse equation, the signals that would occur on the heart surface may be reconstructed.
- the catheter may acquire signals from, for example, two adjacent locations at once, because there are two recording electrodes on the catheter, and those electrodes are located close together. Data may be recorded over one heartbeat during sinus- rhythm, and/or one heartbeat during ventricular tachycardia (and its cycle-length) . Once the data signals are obtained, they are then analyzed according to the procedures described further in the present disclosure.
- the present disclosure can be incorporated into existing clinical methodology for catheter ablation for example, as computer software, or as a standalone computerized data acquisition and analysis system that may be implemented, for example, in software residing on a digital computer, or in hardware components, for example, a specially designed integrated circuit or circuits for maximum speed of processing.
- the target ablation area may be output to a display, for example, a CRT monitor, so that the clinician may rapidly make use of the information and guide the catheter or other ablation device.
- the target ablation area and other relevant values may be output in printed or other auditory, visual or tactile form.
- FIG. 13 shows a high-level diagram of a system which may be adapted for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm according to one embodiment of the present disclosure.
- System 70 may include a processor 71, memory 72, hard disk 73, removable storage 74, a display device 76 (for example, a CRT or LCD monitor, which may have a touch screen display for input, a speaker, and a projection display) , and other input/output devices 77.
- a computer system 70 may be a personal or workstation computer, laptop or other portable computing device (for example, PDA) or may be a standalone system.
- the computer system 70 may also include a network interface 78, for example, a wired or wireless Ethernet card, for connecting to a network (for example, the Internet, an intranet, an extranet, a LAN (local area network) , a WAN (wide area network) , a wireless network, a satellite network and other networks) for communication with other electronic equipment.
- the network interface 78 includes the appropriate conventional units for interfacing with the networks, including, for example, Ethernet card, modem, wireless modem, etc. Interfaces for such communication are well known. Therefore, the interfaces are not described in detail here.
- the processor 71 also may be a suitably programmed microprocessor or microcontroller, an application specific integrated circuit (ASIC) , a programmable logic device, or (as one skilled in the art should understand and appreciate) a collection of discrete components suitably laid out and connected on a printed circuit board.
- ASIC application specific integrated circuit
- a computer program embodying the subject matter of this disclosure may reside on or in, for example, the memory 72, hard disk 73 'and/or removable storage medium 74. Also, the computer program may be downloaded to the device or system through network 78.
- the memory 72, hard disk 73 and removable storage 74 also may be used to store, for example, system code, heart signal input data, user input parameters, and patient database values.
- the software components also may include hardware management functions, such as assorted device drivers, including a wireless communication driver if a wireless interface is provided.
- the program and data storage devices may include one or a combination of buffers, registers and memories [for example, read-only memory (ROM) , programmable ROM (PROM) , erasable PROM (EPROM) , electrically erasable PROM (EEPROM) , non-volatile random access memory (NOVRAM) , etc.].
- Other storage devices may include, for example, floppy disk drive, CD (or DVD) drive, hard disk, and other mass storage devices.
- the storage devices may include a storage area network (SAN) .
- the software components also may include a user interface.
- the user interface provides means (in the form of well- known graphical interface elements, such as tables, menus, buttons, drop-down lists, tabs, etc.) for managing and configuring a library of patient data, including heart signal input data, maps, etc. Further, a user, through the user interface, can customize the images to be displayed.
- a voice interface may be provided along with a microphone. Spoken words are picked up through the microphone and converted by applying speech recognition
- a user may give an oral command, which is then converted through speech recognition and triggers operation.
- the input/output devices 77 may include, for example a keyboard, mouse, light pen, tactile control equipment, microphone, printer, scanner, as well as one or more interfaces to electrodes, catheter and other devices.
- Such interfaces may include conventional data acquisition means (for example, one or more analog-to-digital (A/D) converters) or control means (for example, a suitably programmed microcontroller) .
- the system includes one or more interfaces for receiving electrogram signals from the heart during sinus rhythm via electrodes .
- the output may include a series of maps that show, the sinus-rhythm activation characteristics in the infarct border zone, the sinus-rhythm electrogram duration characteristics in the infarct border zone, the location of the estimated reentry isthmus in the infarct border zone, and the location of the estimated best ablation line in the infarct border zone.
- These maps may include numerical coordinates used to guide the clinician as to the correct placement of the catheter to ablate the heart.
- Other information may be output, including, for example, activation maps of reentrant ventricular tachycardia, for example, if such is available, to confirm the computer selection of the target ablation area and provide additional information to the clinician in order to modify the suggested ablation site if necessary.
- the measurement vectors in the XY space of the activation map are used to define which sites are included in the analysis of activation times.
- the regression line is a line having as one dimension, the distance along that measurement vector for which the particular regression was calculated, and as the other, the values of the activation times along the measurement vector at each site.
- FIGS. 3A-3B show database entries depicted as a scatter plot, and one and two-dimensional boundary lines (dotted and dashed respectively) for classification of the primary vector parameters of activation gradient (AG) and activation uniformity (AU) so that it may be predicted whether the patient ventricular tachycardia is due to a reentrant circuit at the recording surface. Either line is used separately for classification purposes.
- the solid circles denote experiments in which monomorphic reentrant ventricular tachycardia occurred.
- the open circles denote experiments in which reentrant ventricular tachycardia did not occur.
- FIG. 3A shows the relationship between AG and AU for data obtained in approximately 50 canine experiments.
- the canine heart model is not precisely the same as reentrant ventricular tachycardia in humans, there is a close correspondence and hence the scatter plot data serves as a model or guide for human patients.
- Each point represents the AU and AG of a primary vector from each canine experiment in the two-dimensional (XY) space.
- the lines drawn in the scatter plot denote the best one- dimensional (vertical line) and two-dimensional (horizontal line) boundaries for classifying those canine hearts in which it is predicted that reentrant ventricular tachycardia will occur at the recording surface versus those in which it is predicted not to occur. For the canine experiments whose AG/AU point is plotted to the left of the lines, reentry is predicted to occur.
- reentry is predicted not to occur at the recording surface.
- reentrant ventricular tachycardia is predicted not to occur at the recording surface, it may still occur at the opposite surface of the heart or in the interior of the heart.
- recordings were made in the canine heart along the epicardial surface.
- Reentry may occur at the endocardial surface in these cases.
- Ventricular tachycardia in some of these experiments may be caused by a focal point rather than a reentry loop. Such information is highly important to the clinician during ablation therapy.
- the parameters used are the activation gradient and the electrogram duration. Similar results as those of FIG. 3A are obtained. The parameters can be used to predict whether or not reentrant ventricular tachycardia will occur with the same accuracy as in FIG. 3A.
- the activation gradient (AG) alone is a good classifier of whether or not reentrant ventricular tachycardia will occur, as can be seen by the vertical line (one-dimensional boundary) in each figure.
- the activation uniformity (AU) of FIG. 3A and the electrogram duration of FIG. 3B alone would not be good classifiers, for example, a one-dimensional boundary or line in the horizontal direction, may not provide a good classifier either in FIG. 3A or in FIG. 3B.
- FIG. 6 shows a sample regression line diagram according to one embodiment of the present disclosure.
- the axes are the distance along the measurement vector (X-axis) and the activation time at the recording site located at each distance (Y-axis) .
- There are 5 points which is the number of values used for the experimental study of Ciaccio et al, July 31, 2001, and for the clinical study of Ciaccio et al submitted.
- a minimum number of points for example, 5, may be used.
- the line in the graph is the regression line, which is the line at which the mean distance to the points is minimized based on the least- squares error criterion.
- FIG. 7 provides a flow chart diagram of one embodiment of the method according to the present disclosure.
- a catheter may be positioned within the left ventricular chamber of the heart during sinus-rhythm, and electric measurement signals may be recorded from throughout the surface of .the heart at different recording sites during sinus-rhythm using a catheter attached to a data acquisition device.
- a noncontact probe or electrode array for example, a basket catheter, these recording measurements may be made simultaneously.
- a standard ablation catheter with two electrodes is used, the recoding measurements may be made in turns.
- an activation map (FIG. 1A) and an electrogram duration map (FIG. ID) may be constructed based on the recorded signals in Step S102.
- the measurements may be mapped from the recording sites onto their respective portions of the heart .
- Step S104 based on the activation map, the last-activating region XY center, shown by the cross-hair in FIGS. 1A, ID, 2A, and 2D, may be determined by comparing the activation times of the recorded sites, and the method may select a number of sites in a region having latest activation times.
- the latest activation region may include, for example, a contiguous region of five or more sites .
- the measurement vectors may be positioned with the hub at the XY center.
- the measurement vectors may be marks, for example, at some equal spacing 1 centimeter apart.
- the recording site which is closest to it in the XY directions may be chosen as the site whose activation time is used as the measurement value for that point. This may be done for marks along each measurement vector, for example, for 5 marks.
- the linear regression of these times may be computed according as shown, for example, in FIG. 6, which shows a plot of the linear regression line.
- the last-activating region XY center is determined and, in Step S106, vectors may be chosen with origins at the last- activating region XY center.
- vectors may be chosen, for example, as 8 vectors separated by a difference in orientation of 45 degrees with one vector oriented directly vertical in the map. Activation times may then be determined along the vectors originating from the XY center.
- Step S108 linear regression is computed for the times along each vector.
- Linear regression assumes an association between the independent and dependent variable that, when graphed on a Cartesian coordinate system, produces a straight line.
- Linear regression finds the straight line that most closely describes, or predicts, the value of the dependent variable, given the observed value of the independent variable.
- the corresponding value for y either increases or decreases by bl, depending on the sign of bl .
- Linear Regression is a parametric test, that is, for a given independent variable value, the possible values for the dependent variable are assumed to be normally distributed with constant variance around the regression line.
- Linear regression routines work by finding the best fit straight line through the data points.
- best fit it is meant that the line is optimally positioned, based an error criterion, so that the mean distance to all the points on the graph is minimized.
- the error criterion used is called the least squares error, or sum of the distances from each point to the point on the line that forms a perpendicular angle.
- step S110 the activation gradient (AG) and uniformity (AU) which are, respectively, the slope of the regression line and the coefficient of linear regression, are determined from the activation times along each vector.
- the method of the present disclosure searches for a primary axis vector.
- the primary axis vector is the vector with activation gradient and uniformity within a specified range, for example, the vector with steepest gradient and greatest uniformity if more than one vector have parameters in range.
- the steepest gradient is that in which there is the largest change in activation time per unit distance along the vector, for example, ⁇ t/ ⁇ x is maximized, where t is the activation time and x is the distance along the measurement vector.
- t the activation time
- x is the distance along the measurement vector.
- the conduction velocity is the inverse of the activation gradient, for example, ⁇ x/ ⁇ t and therefore conduction velocity is diminished as the activation gradient increases .
- the scale may be reversed, for example, 1.33/0.2 ⁇ 6.5, which is the slope of the regression line for a conduction velocity of, for example, 0.75m/s.
- a regression line slope of, for example, -6.5 or steeper (greater negative value) may indicate the conduction velocity is at or below, for example, 0.75m/s.
- conduction velocity falls below about, for example, 0.25m/s, the area may not be one in which the reentrant circuit isthmus will form.
- there may be a range of sinus-rhythm gradients in which reentrant ventricular tachycardia would be expected to occur.
- Uniformity is the proximity of the coefficient of linear regression to 1.0. At 1.0, all of the points in the regression plot are on the regression line and there is perfect uniformity of conduction all along the location of the measurement vector. The minimum value that the coefficient of linear regression may have is 0.0 which means that the points in the regression line scatter plot are completely random; there is no uniformity. Higher uniformity means that the individual or local conduction velocities, i.e., the distance between any two sites divided by the distance in activation times between those same sites, become more and more similar from site-to-site among the sites used for analysis along a measurement vector .
- Step S114 the method of the present disclosure then may search for an XY center of another region with contiguous, late-activation times. If there is an XY center of late-activating region of sinus-rhythm with parameters within range, (Yes, Step S114) then the method returns to Step S106, where vectors are chosen based on the new XY center and the method continues.
- the process for searching for any XY center of late- activation may be performed as follows. Determine late sites at which adjacent or neighboring sites activate earlier in time.
- a late site is a site whose activation time follows that of all neighboring sites. These neighboring sites can be those, for example, closest to it in the vertical, horizontal, and diagonal directions. From the time of a given late site, include in the late- activation area of that late-site those contiguous sites with activation preceding the late site by a predetermined number of milliseconds, for example, 10 milliseconds. If the late site plus the recording sites contiguous with it are greater than some number for example, 5 sites in total, then count the area so formed as one of late-activation.
- determine whether or not a primary axis in-spec that is, with activation gradient and activation uniformity along the primary axis meeting the more stringent threshold criteria of S112, is present first at the last-activation regions whose late site activates last among all of the late sites. If no measurement vector meets the more stringent threshold criteria of S112, continue this procedure for the last-activation region whose late site activates next-to-last among all of the late sites.
- Step S116 the vector with steepest gradient within a pre-specified range that is also within a pre-specified range of uniformity may be chosen as the primary axis and the method continues to Step S120.
- the more stringent ranges specified in the initial search for a primary axis vector in Step S112 may not be the same as those ranges specified in the subsequent search for a primary axis vector in Step S116.
- the less stringent ranges used in Step S116 will be a different standard than in Step S112.
- the standard for S112 may be uniformity r 2 between, for example, 0.8 and 1.0, and gradient below, for example, -6.5 to -20 slope of the regression line with conduction velocity between, for example, 0.75 m/s and 0.25 m/s.
- the standard for S116 may be uniformity r 2 between, for example, 0.6 and 1.0, and gradient below, for example, -3.3 to -20 slope of the regression line with conduction velocity between, for example, 1.5 m/s and 0.25 m/s.
- the primary axis vector is a line that may indicate the approximate location of the reentry isthmus, in the sense that the primary vector overlaps a part of the actual reentry isthmus, and the orientation of the primary vector may be approximately in-line with the actual reentrant circuit isthmus.
- the primary axis vector may point in the direction from the location where the activating wavefront enters the isthmus to the place where it exits the isthmus.
- ventricular tachycardia due to a reentrant circuit may not be expected to occur. If reentrant ventricular tachycardia is not predicted to occur, then the clinician may be informed through the computer hardware/software that the ventricular tachycardia episodes are not due to a reentrant circuit. The clinician may then modify the diagnostic procedure accordingly.
- a scatter plot may be used to predict whether ventricular tachycardia will occur at the recording surface for the patient.
- the scatter-plot is a graphical representation of a data base consisting of the data from previous patients or experimental results which are used as exemplars.
- the one- and two-dimensional boundary lines are used to classify any ' new patient (input) for the parameters measured along the primary axis of activation gradient versus activation uniformity (FIG. 3A) , or activation gradient versus electrogram duration (FIG. 3B) . If the point from the new input resides to the left of the one or the two dimensional line, it is predicted that reentrant ventricular tachycardia will occur at the recording surface for the patient; otherwise not. Either FIG. 3A or FIG. 3B may be used for this classification.
- ventricular tachycardia is focal (ectopic) . These tachycardias may be cured if they can be induced. In this case, from the ventricular tachycardia activation map, the point of first activation is the focus, and the clinician may ablate this point to stop tachycardia (there is no circuit or loop, just a point or focus) . In another event, there is reentry, but it is occurring elsewhere in the heart other than the surface (endocardial or epicardial) where recordings are being made.
- the reentry circuit may be located in the epicardium. If the clinician knows the location of the epicardial circuit, it may be possible to ablate through the heart wall from endocardium to epicardium, using a higher radiofrequency energy, to stop tachycardia. This entails more damage to the heart and therefore more chance of morbidity to the patient.
- Step S112 If a primary axis vector is found (Yes, Step S112) then reentry may be predicted to occur, and in Step S118, the location of the primary axis vector may be plotted on the computerized electrogram duration map.
- Step S120 points are determined where the difference in electrogram duration between adjacent sites may be greater than some threshold, for example, 10-15 milliseconds.
- those points may be connected to form a polygonal surface encompassing the XY center of the last-activating region so as to minimize the maximum distance between any two connected points, and minimize the average distance between connected points.
- the surface area of the polygon may be above a pre-defined threshold, for example, 4 centimeters square.
- the polygonal surface may encompass, for example, at least the first 1cm in length of the primary axis that originates from the XY center of the last-activation region.
- the polygonal surface so formed may be an estimate of the location and shape of the central common pathway (isthmus) of the reentrant circuit .
- points on the computerized sinus-rhythm electrogram duration map grid in which the difference in electrogram duration between adjacent sites is greater than, for example, 15 milliseconds may be marked.
- the points may be connected to encompass the XY center of late-activation determined from the sinus-rhythm activation map, and also so as to encompass the first, for example, 1 centimeter, of the location of the primary axis from its origin at the XY center of late-activation.
- the points that are connected may be adjusted so as to minimize the maximum difference between points.
- the points that are connected may be adjusted so as to minimize the mean difference between points.
- the minimum surface area of the polygon formed by connecting the points may be greater than, for example, 4 centimeters squared (cm 2 ) .
- the polygon so formed may be an estimate of the location and shape of the isthmus of the reentrant circuit that forms during ventricular tachycardia.
- the estimated ablation line is determined so as to bisect the estimated central common pathway into halves with equal surface areas, or with unequal areas, for example, 25% and 75%.
- the direction of the ablation line may be perpendicular to the primary axis, where the primary axis approximates the direction of the long-axis of the central common pathway.
- the length of the estimated ablation line may extend across the estimated central common pathway and may extend further, for example, 10%, to ensure the central common pathway is ablated across its entirety.
- the method of the present disclosure may determine whether ventricular tachycardia is due to reentry by plotting the activation gradient and uniformity of the primary axis in a scatter plot with points, for example, from other tachycardias from other patients that were used for learning (exemplars) , as shown, for example in FIGS. 3A and 3B. Based on the location of the new point on either side of the linear or nonlinear classification boundary, whether or not reentry will occur may be predicted. For example, if the data point of the patient lies to the left of the two-dimensional classification boundary line, reentry may be predicted to occur, else not. In FIG. 3A, two 1-dimensional thresholds were used, and in FIG. 3B, a single 2-dimensional threshold was used for classification.
- the reduced stringency criteria may be emplaced in which the best of any of the measurement vectors originating from any of the late-activating centers present may be made the primary vector.
- reentry may be predicted not to occur.
- the AG and AU for this primary vector may be used as a new point in the database for the scatter plot. It may also point to whether the tachycardia may be due to a focus (point source) or whether it may be reentry but located on the other surface of the heart (epicardium versus endocardium) .
- FIG. 11 shows another example of how electrogram analyses may be used to determine areas of the reentrant ventricular tachycardia circuit.
- FIG. 11B is shown the sinus-rhythm electrogram duration map. The numbers denote the electrogram duration in milliseconds for each of the gray levels. In each gray level, the recording sites have electrogram duration in a range around the number associated with the gray level.
- the shortest electrogram duration occurs at the area where the reentrant ventricular tachycardia isthmus forms, as is most often the case in clinical and experimental cases. Overlapping the electrogram duration map are the locations of the arcs of conduction block that form during reentry (thick curvy black lines) and the unidirectional arc of conduction block location that forms during a premature stimulus. All of the arcs of block partially align with boundaries between areas with disparate sinus-rhythm electrogram duration.
- the activation map during pacing with a premature stimulus is shown in FIG. 11C.
- FIGS. 11D and HE The activation maps during ventricular tachycardia are shown in FIGS. 11D and HE. Reentry is shown to occur. Although the arcs of conduction block are functional, and hence shift from cycle-to-cycle as shown from FIG. 11D to FIG. HE, the general location is unchanged, and the primary axis computed in FIG. HA still overlies the reentrant circuit isthmus in each case.
- FIG. HF is shown a map made using piecewise linear adaptive template matching (PLATM) . These measurements were made during ventricular tachycardia. At each recording site, the PLATM time is the estimated time interval from activation at the local site to activation at the region of the slow conduction zone in the isthmus of the reentrant circuit.
- PLATM piecewise linear adaptive template matching
- the PLATM map does not rely on activation mapping; hence it can provide a clear picture of where to ablate when activation maps cannot.
- FIG. 12 shows a table of Patient Clinical Data.
- the patient number, sex, infarct location, time from myocardial infarct to EP study, drug therapy, and VT cycle length at onset are given.
- Most of the patients are male with a median age of approximately 67 years which is in agreement with the national statistics for this malady.
- ventricular tachycardia can strike years following the actual myocardial infarct.
- Various drug therapies are given to control the malady, but rarely are drug regimens a permanent and optimal therapy for ventricular tachycardia.
- the rapidity of the heartbeat is also shown for ventricular tachycardia in each patient.
- Faster heartbeat (shorter cycle) general equates with increased discomfort and even injury to the patient during periods in which episodic ventricular tachycardia occurs.
- Activation maps were constructed according to the methodology described in the literature, and comparisons were made of activation maps of sinus-rhythm versus reentrant ventricular tachycardia. There were special characteristics that could be observed in the sinus-rhythm activation maps at the location where the isthmus of the reentrant circuit formed during ventricular tachycardia. Namely, the activation wavefront proceeded, during sinus-rhythm, in parallel to but opposite in direction to the activation wavefront during reentry at the location of the isthmus.
- the methodology was expanded to define the exact shape of the isthmus of the reentrant circuit based on sinus-rhythm measurements [17] .
- This involved the sinus-rhythm electrogram duration calculation and map constructed from it for all sites in the border zone. Based on the location of the primary vector or axis, when reentry was predicted to occur, sites surrounding this location with a difference in electrogram duration between them that was greater than a predetermined value (15 milliseconds in papers) were marked on the computerized grid. The locations were then connected to encompass the XY location of last-activation (which is always the origin or tail of the primary vector) and a distance along the primary vector (taken as 1 centimeter in the sinus-rhythm paper [17]) .
- a myocardial infarct was created by LAD ligation in experiments in 54 canine hearts and attempts to induce reentry in canines anesthetized with sodium pentobarbitol were made 4-5 days later by premature electrical stimulation [9] .
- Bipolar electrograms were recorded from 196-312 sites in the epicardial border zone of the anterior left ventricle for 25 experiments with predominantly long-runs of monomorphic reentry (10 beats, mean 181.9 beats) , 11 experiments with short monomorphic or polymorphic runs ( ⁇ 10 beats, mean 4.5 beats), and 18 experiments in which reentry was not inducible.
- Programmed stimulation from the LAD, lateral, base, or center region of the ventricle proceeded using ten SI stimuli followed by a single premature stimulus.
- the premature coupling intervals were successively shortened . on subsequent stimulus trains until reentry was induced.
- the multi-electrode array was placed on the heart with the same edge always positioned along the LAD margin.
- the ventricular area where recording sites in the multi-electrode array were located was considered to encompass the entire infarct border zone.
- Activation maps [9] were created from data obtained from the border zone during sinus rhythm, pacing, and reentry, when it occurred.
- the sinus rhythm map was constructed from an arbitrary cycle at the beginning of the experiment prior to programmed stimulation and pace maps were constructed from cycles of the pace train which led to onset of reentry.
- Reentry maps were constructed from an early cycle of ventricular tachycardia following stabilization of the circuit (long-runs experiments) or for all cycles (short-runs experiments). Inspection of sinus rhythm activation maps in canine hearts in which reentry was inducible suggested that the isthmus entrance and exit, respectively, tended to form along an axis from the area of last to first activity during sinus rhythm.
- the activating wavefront during sinus rhythm was observed to advance in parallel to this axis, with uniform conduction velocity, and in the opposite direction to activation within the isthmus during reentry.
- the XY-center of this region was computed as the mean value of the site locations in the X- and Y-directions, referenced to an arbitrary fiduciary point on the computerized electrode grid.
- the linear regression of activation times was computed along eight rays originating from the geometric center of this last-activating region (45 degree ray separation with orientation such that two of the rays were precisely vertical on the grid) .
- the activation times at four sites along each ray were used for each regression (rays not entirely on the grid were excluded from analysis) .
- the ray with highest r 2 value was termed the primary axis.
- the regression line slope along the primary axis (termed the activation gradient)
- the r 2 value (termed the activation uniformity)
- the electrogram duration defined as that contiguous series of electrogram deflections with no isoelectric segment of >5ms duration, encompassing the time of local activation at the recording site during one cardiac cycle, was also measured for all electrogram recordings obtained during the same cycle used to construct the sinus rhythm activation map.
- Electrogram duration for all sites was mapped using the same computerized electrode grid that was used for activation mapping.
- the mean electrogram duration along the primary axis was graphed versus the activation gradient along the primary axis for all experiments, and the resulting scatter plots were also used to classify experiments in which reentry could versus could not be induced as described above for the activation gradient-uniformity scatter plot.
- the contiguous region so formed was compared to the actual location and shape of the reentry isthmus (delineated by connecting the computerized grid locations of block line endpoints which were superimposed from the reentry activation map) and mean standard error was computed from all experiments.
- the direction designated by the primary axis was considered to be an approximation of the direction of activation through the actual isthmus during reentry.
- a straight line, called the estimated line for ablation was then drawn perpendicular to the primary axis from one edge of the estimated isthmus to the other on the computerized grid.
- the location of the estimated line for ablation was chosen so as to bisect the estimated isthmus into halves with equal areas.
- the percent of the width of the actual reentry isthmus that the estimated line for ablation spanned was then computed and tabulated.
- FIGS. 1A-1D show activation maps for sinus rhythm (FIG. 1A) , premature stimulation (S2) from the center of the border zone (FIG. IB) , and reentry (FIG. IC) , and the electrogram duration map (FIG. ID) for a canine experiment in which only long-runs of monomorphic reentry with a single morphology were inducible.
- Wavefront propagation direction through the isthmus during reentry (FIG. IC) is oriented in parallel but opposite to propagation in the same region during sinus rhythm (FIG. 1A) .
- sinus rhythm FIGS. 1A-1D
- the 5 or more last sites to activate within a 10ms interval have activation times between 60-69ms.
- Nearest to the XY-center of last-activation (+) is a site which activates at time 91ms.
- the locations used to determine the linear regression, which included this site, are denoted by their activation times and the rays are numbered from 1-8.
- the accompanying table shows activation uniformity and gradient for each ray.
- the primary axis has lowest activation gradient (0.41m/s) and is approximately parallel to the isthmus long axis.
- the block lines forming during premature stimulation and during reentry partially align between areas of large disparity in sinus rhythm electrogram duration (for simplicity, only reentry arcs of block are superimposed on the electrogram duration map) .
- boundary points of the estimated isthmus are given by cross-hatched circles (FIG. ID) . This area partially overlaps the actual reentry isthmus whose boundaries are formed by the superimposed arcs of block. Examples of electrograms with differing electrogram duration are shown (insert, FIG. ID) ; within most of the reentry isthmus region, electrogram duration was relatively short. Other long-runs experiments had similar properties to FIGS. 1A- 1D.
- mean activation uniformity and gradient was 0.97 (.01 and 0.67 (.04m/s, respectively.
- the mean sinus rhythm electrogram duration for sites residing within the isthmus area for all experiments was 24.2 (0.4ms (mean of 18.4(2.2 sites per isthmus) which was significantly lower (p ⁇ 0.001) than for the border zone as a whole (34.1 (0.7ms).
- wavefront orientation during sinus rhythm was approximately parallel to the primary axis; therefore the activation uniformity and gradient along the primary axis was proportional to conduction uniformity and velocity, respectively, along the same axis.
- FIGS. 2A-2D show maps from an experiment in which only short-runs of 3-8 beats of monomorphic reentry could be induced.
- the sinus rhythm activation map (FIG. 2A) shows the region where the isthmus forms (shaded) .
- the primary axis (r 2 0.96) approximately aligned with the isthmus long axis and extended from late- to early-depolarizing regions during sinus rhythm (upward vertical direction originating at the larger 50ms isochrone) .
- activation maps of reentry beats 1-2 were similar (second beat is shown in FIG. 2B) .
- the reentry arcs of block partially align at edges between areas with large disparity in electrogram duration (FIG. 2D) .
- Usually short-duration sinus rhythm electrograms are present at the reentry isthmus location.
- the left arc suddenly shifted inward (dotted in FIG. 2C) to align with a different edge of large disparity in electrogram duration (FIG. 2D) .
- the activating wavefront blocked at the narrowest width of the reentry isthmus (not shown) .
- the boundary points of the estimated isthmus are shown (FIG. 2D, hatched circles) and as in FIGS. 1A-1D, they partially overlap the actual isthmus location.
- FIG. 3A shows a scatter plot of activation uniformity and gradient along the primary axis during sinus rhythm for each experiment. Shown are the best threshold to classify experiments using activation gradient alone (dotted line) , and for activation gradient-uniformity in tandem (dashed line) . In 24/25 experiments with long-runs of reentry
- FIG. 3B shows a scatter plot of the mean electrogram duration versus activation gradient computed along the primary axis for each experiment. For comparison the best activation gradient threshold is shown (dotted line; same as in FIG. 3A) .
- the best threshold for electrogram duration/activation gradient in tandem can be used to correctly classify experiments into those with or without inducible reentry with the same accuracy as the activation gradient-uniformity threshold of FIG. 3A.
- the points representing experiments with short-runs of reentry tend to form a curvilinear boundary separating points representing experiments with long-runs of reentry versus no reentry.
- FIGS. 4A-4Y show the estimated reentry isthmus (region with grid lines) , the estimated wavefront direction through it (arrow) , the estimated best line for ablation (dashed line) , and the actual location of reentry arcs of block (thick curvy lines) for each experiment with long-runs of reentry.
- FIG. 4A-4Y are ordered from shortest to longest reentry cycle-length. Shown in FIG. 4W are estimates for the FIGS. 1A-1D experiment (boundary points denoted in FIG. ID). In two experiments (FIGS. 40 and 4Y) , two reentry morphologies occurred and arcs of block are shown for each.
- the estimated best line for ablation extended across most of the width of the actual reentry isthmus (mean 88.2%).
- FIGS. 5A-5K the estimated isthmus parameters are shown for experiments with short-runs of reentry (polymorphic in FIGS. 5A-5E and monomorphic in FIGS. 5F-5K; separately ordered based on cycle-length) .
- polymorphic in FIGS. 5A-5E and monomorphic in FIGS. 5F-5K; separately ordered based on cycle-length
- FIGS. 5A-5C three polymorphic experiments (FIGS. 5A-5C) , only a single late-activating region was detected in the sinus rhythm activation map although there were isthmuses at multiple locations during reentry.
- FIGS. 5D-5E two estimated isthmuses are shown because there were two late-activating regions and therefore two primary axes during sinus rhythm.
- the estimates for the experiment of FIGS. 2A-2D are shown in FIG. 5F.
- the estimated best line for ablation extended across more than half the width of the actual reentry isthmus (mean 55.4%) .
- Uniformity of gap-junctional disarray throughout the region [8] may have been responsible for the uniform activation gradient and therefore conduction velocity uniformity (since the activating wavefront tended to propagate in parallel to the primary axis) .
- Sinus rhythm electrogram duration tended to be short within the isthmus formation area, and longer just outside it, resulting in large differences in electrogram duration at isthmus edges that were used to draw boundary points.
- Electrical activation at depth is often asynchronous with surface activation [11] ; therefore, reduction of electrical activity at depth, due to thinness of the layer, may have acted to shorten electrogram duration within the isthmus region .
- Imprecision in activation mapping due to limited spatial resolution and/or ambiguous time of local activation at any given recording site will affect both the activation gradient measurements and localization of arcs of block.
- Use of a different threshold for electrogram duration measurements could alter the precise locations of boundary points.
- Both multiple deflections (fractionation) and a single wide deflection were considered indicative of abnormal cell presence and wavefront impediment; however, anatomic and histologic correlation to support this hypothesis was not performed in this series of experiments, which is an important limitation of this study.
- the results described herein for functional reentrant circuits in a canine model may not be fully applicable to reentrant ventricular tachycardia occurring in humans, where anatomical arcs of block can occur more frequently [5] .
- Wit AL Janse MJ. Basic mechanisms of arrhythmias. In: Wit AL and Janse MJ, eds . The ventricular arrhythmias of ischemia and infarction. New York, NY: Futura; 1993:1-160.
- EJ Tosti AC, Scheinmann MM. Relationship between Sinus Rhythm Activation and the Reentrant Ventricular Tachycardia Isthmus. Circula tion . 2001; 104: 613-619.
- ventricular tachycardia was suspected to be caused by a reentrant circuit.
- the digital sampling rate was 1 kHz and the band pass frequency range was 0.5 - 500Hz during the data acquisition and mathematical reconstruction process.
- the 3-dimensional locations of the 256 sites on the virtual endocardial surface (16 virtual sites along each of 16 longitudinal lines around the inside of the endocardial cavity) were translated to a 2-dimensional computerized grid using an Eckert VI projection, which is a pseudocylindrical map in which the central meridian and all parallels are at right angles, and all other meridians are sinusoidal curves. In this type of cartographic projection, some shape distortion occurs at the poles.
- Activation maps of sinus-rhythm, ventricular pacing, and ventricular tachycardia were made by first marking activation times of the unipolar electrogram signals. Computer software was used to manually determine the point of sharpest slope in the signal [10] , or the center point if multiple deflections with sharp slopes were present. Activation times during a selected cardiac-cycle were then printed on the 2-dimensional computerized map grid. Isochrones were set at 10-40ms intervals, and arcs of conduction block separated sites in which activation differed by >40ms and where wavefronts on opposite sides of the arcs moved in different directions [10] . The arcs were drawn using a cubic spline interpolation program (PSI-Plot Ver.
- PSI which is based on a polynomial equation that minimizes the straight-line distance to a set of boundary points.
- the spline interpolation function generates a curved line that was superimposed on the computerized grid with 0.1mm precision.
- the electrogram duration defined as that contiguous series of electrogram deflections with no isoelectric segment of >5ms duration, encompassing the time of local activation at the recording site during one cardiac cycle, was also measured for all electrogram recordings obtained during the same cycle used to construct the sinus-rhythm activation map [6] .
- Electrogram duration was mapped using the same automated, 2-dimensional computerized electrode grid that was utilized for activation mapping.
- a linear regression of activation times was computed along eight rays originating from the geometric center of this last-activating region (45 degree ray separation with orientation such that two of the rays were precisely vertical on the grid) .
- the activation times at four selected sites along each ray ( ⁇ 0.5cm spacing between sites) , plus the center site itself (five sites in all) , were used for each regression.
- the XY centers of any other late-activating regions on the endocardial surface were computed and the process of searching for a primary axis meeting the above threshold criteria was repeated. If no ray originating at a late-activating region met the criteria, then the ray originating from the last-activating region with the greatest regression coefficient was taken as the primary axis. Presence of a primary axis meeting the threshold criteria was considered to indicate that an endocardial reentry circuit would be detectable in the ventricular tachycardia activation map, and its location and orientation were considered to approximate the isthmus location and wavefront propagation direction through the isthmus during reentry. Whereas, absence of a primary axis meeting the threshold criteria was considered to indicate that a complete endocardial reentry circuit would not occur during tachycardia.
- the isthmus shape was estimated as follows. First areas of the sinus-rhythm electrogram duration map in which the difference in electrogram duration between any two adjacent sites was 15ms was marked on the computerized grid as described previously [6] . Selected marks around the primary axis were connected by computer methodology so as to form the border of a contiguous region which minimized the distance between the boundary points while maintaining the surface area of the enclosed section above a minimum constraint [6] . The contiguous region so formed was termed the estimated isthmus.
- the percent that the estimated best ablation line spanned the actual reentry isthmus determined by activation mapping was also computed and tabulated.
- the average of these two lengths was taken as the skeletonized isthmus length.
- the distance between the endpoints of the arcs of block at the isthmus entrance and also at the isthmus exit was then determined.
- the average of these two distances was taken as the skeletonized isthmus width.
- the minimum distance between the two arcs of conduction block was termed the skeletonized narrowest-width of the isthmus.
- PKATM was also used to approximate the timing from activation at each virtual recording site on the left ventricular endocardium to activation at the SCZ center
- the paradigm is based on measurement of phase shifts in the far-field deflections of the extracellular signal, which are reflective of alterations in SCZ conduction velocity [8-9] .
- Non-contact activation maps revealed that tachycardias in 11/14 patients were associated with an endocardial reentry circuit having a "figure-8" conduction pattern [5] . Examples from four cases are shown in FIGS. 8A-8D.
- the north and south poles of the 3-dimensional electrode distribution from the non-contact data are represented, respectively, by the top and bottom edges of the 2-dimensional grids in FIGS. 8A-8D.
- the left and right edges of the grids represent the place where the 3-dimensional electrode distribution was separated at a line of longitude; these edges are actually continuous with one another in 3-dimensional space.
- the wavefront courses through the reentry isthmus which is bounded by arcs of conduction block (thick curvy black lines) , with arrows denoting the direction of wavefront propagation.
- the wavefront bifurcates and travels as separate wavefronts outside the arcs of conduction block and away from the isthmus.
- an arc of conduction block extends outward across the left edge of the map and continues inward from the right edge.
- FIGS. 8A-8D the separate wavefronts coalesce at the isthmus entrance. Cycle-length at onset for all tachycardias are given in FIG. 12.
- the mean cycle-length at onset for the 11 patients with reentrant tachycardia was 331ms, and the mean skeletonized isthmus length, width, and narrowest-width were 5.5cm, 4.7cm, and 2.2cm, respectively.
- FIGS. 9A-9B is given an example of sinus-rhythm electrogram analysis measurements (patient 5 from FIG. 12) . Shown are the sinus-rhythm (FIG. 9A) , premature stimulation (FIG. 9C) , and reentry activation maps (FIG. 9D) .
- the XY center of last-activation is denoted at the site marked "52", and the eight rays projecting from it that were used to make measurements of activation gradient and uniformity are shown in FIG. 9A, with some wrap-around to the other side of the grid) .
- Shown in FIG. 9B is the electrogram duration map (examples of the endpoints in duration for selected electrograms are given in the inset) .
- the primary ray is located within a region of short electrogram duration, and the estimated isthmus and estimated best ablation line (see Methods section) are denoted by the dashed polygon and dotted line, respectively, overlaid on the map grid (FIG. 9B) .
- During premature stimulation (FIG.
- a primary axis meeting the threshold criteria given in the Methods overlapped the reentry isthmus location and was in parallel with the isthmus long-axis. Whereas, a primary axis meeting the threshold criteria was absent in all 3 patients lacking a complete endocardial reentry circuit (patients 11 and 13-14) .
- FIG. 10 the overlap of estimated isthmus (area enclosed by dashed line) versus the actual isthmus determined by activation mapping (gray surface bounded by superimposed arcs of block indicated by thick black lines) is shown for all 11 patients with "figure-8" reentry. The location and direction of the primary axis is given by the arrow. Frequently there is a close overlap (patients 1-2, 5-8) and the estimated best ablation line (dotted line) spans most or all of the actual isthmus width (patients 1-3, 5, 8-9, and 11) . For all 11 patients, the mean overlap of the estimated isthmus with the actual isthmus was 74.2% and the estimated best ablation line spanned the actual reentry isthmus width by a mean of 83.1%.
- FIGS. HA-llD show an example of how PLATM9 can be used to measure the time interval from local to SCZ activation (patient 9 from FIG. 12) .
- the activation and electrogram duration map of sinus-rhythm are shown in FIGS. HA-llB, and an activation map during pacing, and during tachycardia for short and long cardiac-cycles are shown in FIGS. HC- HE respectively.
- Electrogram duration is short within the area where the isthmus forms (FIG. HB) .
- an arc of block forms (thick black line, FIG.
- PLATM isochrones increase negatively in the direction distal to the SCZ in the circuit (meaning that SCZ activation has occurred previous to local activity) and PLATM isochrones increase positively in the direction proximal to the SCZ (meaning that SCZ activation occurs following local activity) .
- PLATM estimated the time interval from local to SCZ activation with a mean error of 19.4ms.
- the arcs of conduction block which formed- during premature stimulation and during reentry tended to overlap lines of sharp transition in sinus-rhythm electrogram duration (see FIGS. 9B and 9D, FIGS. HB, 11C and HD) .
- Such boundary areas may separate regions with discontinuous electrical properties characterized by an increased effective axial resistivity [12], which would account for the slow conduction or block that was observed to occur in these regions during premature stimulation and during tachycardia.
- Steep transition in sinus-rhythm electrogram duration also occurred elsewhere in the infarct border zone
- unidirectional arcs of conduction block can also form at these regions of the border zone during premature stimulation [6] .
- isthmus formation region where activation during sinus-rhythm was measured to be slow and uniform, that there is most likely to be sufficient delay following premature stimulation, formation of the unidirectional arc of conduction block, and wavefront travel around the arc, so that there is recovery of excitability and genesis of reentry.
- the time for recovery of excitability is insufficient and reentry cannot occur.
- results of analysis of sinus-rhythm electrograms suggests the possibility that the reentrant circuit isthmus can be located without the necessity for induction of ventricular tachycardia; however, this hypothesis requires further testing.
- the results of tachycardia electrogram analysis described in this study have a number of implications for ablation of tachycardia. That the ends of the arcs were not permanent fixtures during periods of reentry cycle-length change offers a possible explanation as to why radiofrequency catheter ablation may stop tachycardia that is induced during clinical electrophysiologic study, but tachycardia is sometimes reinducible thereafter [4] .
- the translation of the 3-dimensional virtual electrode array location onto the 2-dimensional grid causes some distortion in the shape of the reentry isthmus and the pattern of activation.
- the mathematical reconstruction process is most accurate at the equatorial regions of the non-contact catheter; circuits with components near the polar regions are likely to be less accurately represented in the activation maps [1-2] .
- the electrogram analyses described herein were relative measurements and hence by reverse distortion, parameters are correctable to the original 3-dimensional space. A relatively low spatial resolution of recording electrodes was used in the study
- Ciaccio EJ Tosti AC, Scheinman MM. Relationship between sinus rhythm activation and the reentrant ventricular tachycardia isthmus. Circulation . 2001; 104: 613-619.
- Ciaccio EJ Costeas CA, Coromilas J, et al. Static relationship of cycle-length to reentrant circuit geometry. Circulation, 2001; 104:1946-1951.
- Ciaccio EJ Dynamic relationship of cycle length to reentrant circuit geometry and to the slow conduction zone during ventricular tachycardia. Circulation 2001; 103:1017-1024.
- Ciaccio EJ Localization of the slow conduction zone during reentrant ventricular tachycardia. Circulation 2000; 102: 464-469.
- a canine infarct model of reentrant ventricular tachycardia in the epicardial border zone with a figure-8 pattern of conduction was used for initial analysis (experiments in 20 canine hearts with monomorphic reentry) .
- Sinus-rhythm and reentry activation maps were constructed, and quantitative
- Tachycardia cycle length measured from the ECG R-R interval, increases with increasing isthmus length, width, narrowest width, angle with respect to muscle fibers, and circuit path length determined by use of sinus-rhythm measurements. After this procedure, in 5 test-set experiments, tachycardia cycle length measured from the R-R interval, in combination with regression coefficients calculated from initial experiments, correctly predicted isthmus geometry (mean estimated/actual isthmus overlap 70.5%) .
- circuit path length determined with sinus-rhythm measurements correctly estimated the tachycardia cycle length (mean error 6.212.5 ms) . Accordingly, it is shown that correlation relationships derived from measurements using reentry and sinus-rhythm activation maps are useful to assess isthmus geometry on the basis of tachycardia cycle length. Such estimates may improve catheter ablation site targeting during clinical electrophysiological study.
- catheter ablation is often the method of choice because it does not involve surgery, there is low morbidity, and it is frequently effective at stopping tachycardia and preventing recurrence .
- the target site for ablation of reentry is the central common pathway, or isthmus, which is a protected region through which the propagating wave front is constrained by arcs of conduction block.
- isthmus which is a protected region through which the propagating wave front is constrained by arcs of conduction block.
- Some reentrant circuits are difficult to ablate during clinical electrophysiological study because it is problematic to ascertain the precise location and/or geometric characteristics of the isthmus .
- a fixed signal gain of xlOO was used for first-stage amplification, and a xl to xl28 gain determined automatically by computer software was used for second- stage amplification, so that the final signal peak-to-peak level was between 2 and 8 V.
- the signal pass band was 2 to 500 Hz.
- data were acquired during sinus rhythm, pacing, and monomorphic reentrant ventricular tachycardia with figure-8 conduction pattern [10] that was induced by programmed electrical stimulation (10 Spacing cycles followed by a premature stimulus) .
- Activation maps were made by automatically marking activation times of electrogram signals by slope and peak criteria and printing the times for all sites on a computerized map grid.
- FIG. 17A shows, for a selected canine heart experiment, the reentry activation map for the first cycle of tachycardia after onset in which the cycle length had stabilized, which was determined as described previously for this model.
- the reentry isthmus is bounded by 2 arcs of block (locations are shown as superimposed thick curved black lines) .
- Activation proceeds through the isthmus toward the apical margin of the border zone and then bifurcates and turns upward in the map toward the LAD basal border.
- Muscle fiber direction was determined from an activation map constructed from center pacing during sinus rhythm (FIG. 17C) . Fiber angle was considered to be in parallel with the direction of the most rapid electrical conduction away from the paced zone, which is toward the LAD and toward the apex in the map. Separate maps were constructed of individual skeletonized reentry parameters for each experiment at the onset of stable tachycardia cycle length and for the mean skeletonized parameters from all experiments .
- Sinus-rhythm data without pacing were then used to measure a parameter called the electrogram duration.
- This parameter is defined as that contiguous series of electrogram deflections, with no isoelectric segment of >5 ms duration, encompassing the time of local activation at the recording site during 1 cardiac cycle.
- the starting and ending points, respectively, were considered to be the beginning and ending times at which contiguous electrogram deflections rose above the isoelectric level to an amplitude >10% of the maximum electrogram peak.
- Electrogram duration was mapped by use of the same automated, computerized electrode grid that was used for activation mapping. An example is shown in FIG. 17D, in which reentry arcs of block locations are superimposed as thick curved lines .
- the shortest pathway around either of the superimposed arcs of block for which electrogram duration was ⁇ 40 ms was computed methodically as follows. A minimum number of piecewise linear segments were positioned on the map grid at locations around the arc of block such that the entire pathway was constrained to areas of short ( ⁇ 40-ms) electrogram duration. Path length was then equal to the summed lengths of the piecewise linear segments.
- the significant correlation coefficients (P ⁇ 0.001) determined from the 20 training-set canine heart experiments were used to assess 5 test-set canine heart experiments.
- the reentry cycle length measured from the ECG R-R interval, in conjunction with the linear regression coefficients determined from the training-set experiments was used to provide an estimate of the isthmus geometry (shape and orientation) .
- the estimate of skeletonized angle with respect to muscle fiber orientation was unsigned, for simplicity it was chosen in the direction for best overlap with the actual reentry arcs of block determined from activation mapping.
- the isthmus centers were made coincident on the computerized grid, and as a first approximation, the narrowest width was drawn at the center of the estimated isthmus.
- the center of the actual isthmus was taken as the mean XY location of the 4 end points of the arcs of block, and the center of the skeletonized isthmus was taken as the midpoint of the angle vector.
- the area percent by which the skeletonized isthmus overlapped the actual isthmus was then computed for each test set.
- FIGS. 18A-18T show maps of selected skeletonized isthmus parameters for each experiment, from the measurements of observer 1, with the maps ordered according to cycle length.
- the reentry circuit of FIG. 17A-17E is shown in FIG. 181. Isthmuses with greatest cycle length tended to be larger in both length and width (FIG. 18A through 18L) . In many of the maps, the wave front propagates through the reentry isthmus toward the LAD basal margin. There is no evident relationship of cycle length with XY location.
- the mean skeletonized circuit from the 20 training-set experiments is shown in FIG. 19.
- Mean skeletonized isthmus length, width, and narrowest width were 20.3 mm, 18.4 mm, and 10.8 mm, respectively, and mean tachycardia cycle length was 198.8 ms .
- the mean isthmus angle was 23.4" to the left of vertical in the map, approximately in line with muscle fiber orientation at the mean XY isthmus location for all experiments.
- the isthmus is narrowed near its center, and slower conduction occurs there and at the pivot points around the arcs of block. Conduction velocity is rapid at the isthmus exit and along the straightaway locations outside the isthmus.
- FIG. 20 shows a table of significant correlation relationships between skeletonized variables at the onset of stable tachycardia cycle length.
- Tachycardia cycle length (CL) is highly correlated with the path length (PL) determined during sinus rhythm (Equation ) .
- PL path length
- Equation 1 There is a second-order relationship between skeletonized isthmus length and width (Equation 1) , isthmus length and angle are correlated with cycle length (Equations 2 to 4) , and narrowest width is correlated with width (Equation 5) .
- isthmus length is likely to be constrained by the possible range in cycle lengths.
- the length of the isthmus cannot increase such that it prolongs the tachycardia cycle length beyond the time that a sinus escape beat would occur.
- isthmus length cannot decrease below a level at which it would result in arrival of the activating wave front at a particular portion of the circuit during the relative refractory period (causing slowed conduction) and/or during the absolute refractory period (causing block) .
- conduction velocity diminished with increasing angle of the isthmus away from muscle fibers tachycardia cycle length also increased (Equation 3), in agreement with experimental and theoretical studies of the anisotropic relationship between these variables.
- the sinus-rhythm electrogram duration parameter was a measurement of the electrical activity occurring in proximity to the recording electrode and did not include isolated late potentials (see Methods section) ; hence, this measurement would be expected to be influenced by factors affecting local activity only, such as wave- front conduction velocity near the recording site.
- wave- front conduction velocity near the recording site.
- relatively rapid conduction occurred as the propagating wave front coursed around the left block line (FIG. 17A)
- sinus-rhythm electrogram duration there was relatively short path denoted PL in FIG. 17D
- relatively slow conduction occurred around the right block line, particularly along the lateral edge of the map grid (FIG.
- FIG. 19 shows the mean skeletonized parameters; the mean isthmus from all experiments approximately aligns with muscle fiber orientation at the mean XY location.
- This phenomenon may be related to the setup of tachycardia: during premature stimulation leading to reentry onset, a unidirectional arc of block forms, and the wave front bifurcates and proceeds around it. The same wave front coalesces on the other side of the unidirectional arc and breaks through to reenter the previously excited tissue if there is sufficient delay for recovery of excitability. Wave front traversal around the arc will be slowest (hence, the greatest chance for delay necessary for reentry induction) if it propagates perpendicular to muscle fiber orientation.
- the isthmus long axis which generally aligns in parallel with the direction of reentry breakthrough during the premature cycle, [13] would most commonly reside in parallel with muscle fiber orientation, as was observed. Also in FIG. 19, the narrowest portion of the isthmus is coincident with the zone of slow conduction. This may be the result of an aperture effect in which insufficient current is available for normal activation as the wave front proceeds out of the aperture and into an area of distal expansion. [16]
- Correlation between the skeletonized variables can potentially provide information concerning the range of possible shapes that the reentry isthmus may possess.
- the strong second-order relationship between skeletonized isthmus length and width (FIG. 20, Equation 1) can be stated as follows. When the reentry isthmus is narrow in this canine model, it tends to be either long or short in length, and when it is wide, it tends to be of intermediate length. An isthmus having large dimensions of both length and width may be uncommon, because the path length could prolong tachycardia cycle length to the extent that a sinus-rhythm escape beat would capture conduction of the heart.
- isthmus shape could be estimated by use of skeletonized regression coefficients in conjunction with a measurement of tachycardia cycle length from the ECG R-R interval, it would be of potential benefit for targeting ablation sites to know a priori the characteristics of the isthmus that are of importance for determining the best lesion length and orientation.
- tachycardia cycle length from the patient's ECG would be done before electrophysiological study, recorded, for example, with a Holter monitor, so that ablation therapy could be planned accordingly.
- the skeletonized isthmus angle estimate described here is unsigned; hence, there are 2 possible orientations with respect to muscle fiber direction (+/-) .
- the reentry circuit path length which was measured by use of the sinus-rhythm electrogram duration parameter, was also found to be highly correlated with tachycardia cycle length measured from the ECG R-R interval.
- tachycardia cycle length was correctly estimated (mean error 6.2+2.5 ms) .
- Estimation of tachycardia cycle length before tachycardia induction during clinical study, using isthmus boundaries determined from sinus rhythm measurements, [13] is potentially useful to gauge toleration of the tachycardia by the patient and the effect of any arrhythmic drug to be administered during tachycardia, both of which are in part rate-dependent. [14]
- Isthmus arcs of block were localized by spline interpolation to 0.1 mm, which was beyond the 4- to 5-mm resolution of the multielectrode array but consistent from one activation map to the next. Any inaccuracy in placement of the arcs of block may serve to decrease the significance of correlation between variables; higher electrode spatial resolution may reveal other geometric variables with significant correlation.
- the simple measurements used to gauge isthmus geometry are not indicative of subtle features of the circuit. For improved representation, more sophisticated geometric measurements might be useful; however, the complexity of analysis would increase. At present, it is unknown how the properties of functional circuits for the canine model described here might apply to ventricular tachycardia circuits in human patients, in whom the isthmus may more frequently be bounded by anatomic arcs of block.
- Skeletonized geometry methods may also be useful to assess the effect of isthmus orientation with respect to muscle fibers on the action of antiarrhythmic drugs that preferentially impede conduction in either the longitudinal or transverse direction.
- Ciaccio EJ Dynamic relationship of cycle length to reentrant circuit geometry and to the slow conduction zone during ventricular tachycardia. Circulation . 2001; 103: 1017-1024.
- Ciaccio EJ Tosti AC, Scheinman MM. Relationship between sinus rhythm activation and the reentrant ventricular tachycardia isthmus. Circulation . 2001; 104: 613-619.
- Wit AL Janse MJ. Basic mechanisms of arrhythmias . In: Wit AL, Janse MJ,eds. The Ventricular Arrhythmias of Ischemia and Infarction. New York, NY: Futura; 1993: 1-160.
- Sinus rhythm activation and electrogram duration maps were constructed from bipolar electrograms acquired at 196-312 sites in the epicardial border zone of 43 canine hearts (25 with reentrant ventricular tachycardia inducible by premature stimulation and 18 lacking inducibility) . From these maps, lines of electrical discontinuity where block would occur during premature excitation were estimated. The mean error in distance between the estimated and actual block line of premature excitation was 0.97cm. Based on the quantitative characteristics of the activation and electrogram duration maps and the longest block line forming during premature excitation, whether or not reentry would occur was predictable (sensitivity 94.7%, specificity 79.6%) .
- sinus rhythm electrograms were used for measurement because in these signals it is relatively simple to quantify the interval of local activity and the starting points of isoelectric intervals, compared with signals obtained during ventricular pacing or ventricular tachycardia, as described below.
- a myocardial infarct was created by ligation of the left anterior descending coronary artery (LAD) in si tu in experiments in 43 canine hearts. Four to five days later, canines were anesthetized with sodium pentobarbitol
- bipolar electrode multiarray was then sutured onto the anterior surface of the canine heart for recording and stimulation.
- Bipolar electrograms were recorded from 196-312 sites in the epicardial border zone of the anterior left ventricle at an average spatial resolution of 4-5mm, and were amplified 100-lOOOx by a computer software auto-gaining procedure.
- the signal pass- band applied prior to digitization of the signals had high and low pass corner frequencies of 2Hz and 500Hz respectively. Attempts to induce reentry were made in these hearts by premature electrical stimulation 5 .
- Stimulating electrodes embedded in the recording multi-electrode arrays enabled pacing from constant locations at the LAD, lateral, base, and center region of the anterior epicardial surface.
- Programmed stimulation proceeded using ten SI stimuli followed by a single S2 premature stimulus.
- the premature coupling intervals were successively shortened on subsequent stimulus trains until reentry was induced or block occurred.
- the electrode multiarray was placed on the heart with the same edge always positioned along the LAD margin.
- the region of the ventricle where recording sites in the multiarray were located was considered to be coincident, to a first approximation, with the entire infarct border zone.
- Activation maps of sinus rhythm, pacing, and reentry were made by automatically marking activation times of electrogram signals at the point of sharpest slope along the largest peak deflection, and printing the times for all sites on a computerized map grid 5 .
- the electrogram was re-marked at the sharpest slope of any electrogram deflection, when present, that more closely coincided with the activation times of neighboring sites. This set of rules was applied to ensure consistency in the activation marking procedure.
- the locations of arcs of conduction block were drawn on the map grid between sites in which activation differed by more than 40ms and where wavefronts on opposite sides of the arcs moved in different directions according to the maps 5 .
- Arcs were drawn using a spline interpolation function to 0.1mm precision, which was beyond the resolution of the electrode multiarray, but consistent from one activation map to the next.
- sinus rhythm electrogram duration maps i.e., activation duration
- Contiguous deflections are those in which there is no isoelectric segment of more than 5ms in length between successive deflections.
- the electrogram duration was used as a distinct measure of the electrical activity in the border zone.
- spline interpolation was used to form a curved line from the points, as described elsewhere 2 .
- This curved line was used as an estimate of the location of the longest (primary) arc of conduction block expected to form during premature excitation. For simplicity, statistics were only computed for the longest arc of conduction block expected to form during premature excitation.
- FIGS. 22A-22I show electrogram maps for an experiment in which reentry was inducible from the basal margin of the grid.
- the sinus rhythm cycle length was 414ms
- ventricular tachycardia with a cycle length of 176ms was repetitively inducible by pacing the heart using ten SI stimuli having a coupling interval of 300ms, followed by a single premature stimulus 145ms later.
- the sinus rhythm activation map is shown in FIG. 22A.
- the locations between adjacent sites where the activation time difference is greater than or equal to 10ms are delimited by solid circles superimposed on the computerized mapping grid. Based on the positions of the points, curved lines were drawn by spline interpolation which were the predicted locations of conduction block during premature excitation
- FIG. 22A The sinus rhythm electrogram duration map for the cycle of FIG. 22A is shown in FIG. 22B, with the grayscale at top denoting the relationship between gray level and the duration of the electrogram in milliseconds.
- the estimated breakthrough point located at the area with shortest electrogram duration along the longest block line anticipated to occur during premature excitation, is denoted by the center of the blue arrow superimposed on the map of FIG. 22B. Smaller differences in activation time tended to occur across the estimated breakthrough point where electrogram duration was shortest
- FIGS. 22A and 22B When paced from the center of the epicardial border zone at a coupling interval of 350ms (activation map of FIG. 22C) , conduction was most rapid in the direction denoted by the arrows. Based on anisotropic considerations in which the activation wave-front proceeds most rapidly in parallel with the long-axis of normal myocardial cells 1 , the arrows therefore approximate muscle fiber orientation in the border zone (i.e., coursing from LAD to APEX) . Since the multielectrode grid was positioned with the same side overlapping the left anterior descending coronary artery of the heart in all experiments (see Methods section) , muscle fiber orientation was approximately the same for all maps constructed for this study.
- the direction of the oncoming wave-front to the long line of electrical discontinuity is approximately normal, i.e., activation all along the top, horizontal portion of the line occurs at approximately time 40ms and activation along most of the bottom, vertical portion of the line occurs at approximately time 80ms (FIG. 22E) .
- Illustrated in FIG. 22F are some of the quantitative methods used for comparative calculations: the outer bounds of the surface area between estimated and actual arcs of block (crisscross region) , the distance between estimated and actual breakthrough points (short line between the solid circles, enlarged in inset) , and the symmetry of the ends of the arcs of block to the stimulus site location (gray lines) .
- FIGS. 23A-23Y show the results of sinus rhythm electrogram measurements for the 25 experiments with inducible reentry.
- the estimated versus actual longest block-lines to form during a premature stimulation cycle which resulted in initiation of reentry are shown, respectively, by blue and black curved lines.
- the coupling interval of this premature stimulation cycle ranged from 135ms (FIG. 23Q) to 220ms (FIG. 23E) .
- the coupling interval of premature- stimulation that resulted in reentry onset changed by no more than 10-20ms between episodes of induction, and reentry could only be induced by stimulation at the site location denoted by the red pacing symbol for each of the experiments of FIGS. 23A-23Y.
- Premature excitation resulted in tachycardia when the stimulation site was located at the LAD margin in 13 experiments, at the basal margin in 6 experiments, at center in 5 experiments, and at the lateral margin in 1 experiment.
- the LAD and basal stimulus site locations appear in relatively close proximity in the two-dimensional activation maps of FIGS. 23A-23Y.
- examples of pacing locations at the basal and LAD margins are denoted in FIG. 23B and 23D respectively.
- examples of pacing locations at the basal and LAD margins are denoted in FIG. 23K and 23L, respectively.
- the site at which a premature stimulus resulted in reentry was in an area where sinus rhythm activation was rapid.
- FIGS. 23A-23Y The estimated and actual breakthrough points (centers of blue and black arrows, respectively) are also shown in FIGS. 23A-23Y. In each case the difference in sinus rhythm activation time was relatively short at the estimated breakthrough point (not shown) .
- FIG. 23F The details for the experiment of FIG. 22 are depicted in FIG. 23F.
- two reentry morphologies were inducible via premature stimulation and the location of the second isthmus is shown in red color.
- FIG. 23Y breakthrough occurred across two arcs of block and dual isthmuses were present during the same reentry morphology. In all of the figures, there is often a close correspondence between the estimated and actual arcs of conduction block and the breakthrough points.
- the longest estimated and actual arcs of conduction block had mean lengths of 6.53 + 0.51 cm and 6.14 + 0.53 cm, respectively, for reentry experiments, and 2.21 + 0.34 cm and 2.31 + 0.34 cm, respectively, for experiments in which reentry was not inducible. Therefore, in experiments with reentry inducibility, the mean length of the long arc ' of block forming during premature excitation was approximately thrice that of experiments lacking inducibility.
- the arcs of conduction block forming during reentry are also shown in FIGS. 23A-23Y, denoted as dashed gray lines, with a gray arrow indicating activation direction during the diastolic interval of reentry.
- FIGS. 24A-24C Scatter-plots of the electrogram parameters described in FIG. 25 that could be used for classification, with an accuracy greater than 80%, of the 43 experiments into those with versus lacking reentry inducibility, are given in FIGS. 24A-24C.
- Equation 3 the time interval for the activation wave-front to propagate from the premature stimulation site to the breakthrough point is prolonged (Equation 3) , which in turn is related to an increased difference in activation time on opposing sides of the breakthrough point during the premature excitation cycle (Equation 4) .
- Equation 4 A long estimated arc of conduction block, and a large difference in activation time on opposing sides of the predicted breakthrough point during the premature excitation cycle, are highly predictive that reentry will actually occur (FIGS. 24A and 24C) .
- induction of reentry is directly related to the status of the border zone during sinus rhythm, as can be determined by quantification of electrogram shape, and to the resulting pattern of activation during premature excitation.
- the probability is increased that block will occur along a long continuous portion of this tissue when the infarct border zone is excited prematurely.
- the resulting long arc of conduction block delays the arrival time of the activation wave-front to the opposite side of the arc. If this delay is sufficiently long so that there is recovery of excitability in the initially activated region, breakthrough across the arc of block will likely occur to initiate reentry.
- arcs of conduction block tend to be functional, i.e., their occurrence depends on transient electrical properties including the time for recovery of excitability during a particular activation cycle, the wave-front orientation, and the quantity of current available for activation 1 ' 5 .
- the actual locations where functional arcs of block form both during premature excitation and during reentry tend to be constrained to localized regions of the infarct border zone in the canine hearts 5 , and can also possess similar properties of constancy in patients 6 , although the exact correlation between reentry in canine and human hearts is presently uncertain, due in part to differences in infarct ages.
- the estimated locations of arcs of conduction block forming during premature excitation tended to be concave in shape with respect to stimulus site position, and in a few experiments formed an approximately closed contour (FIG. 23C, 23D, 23N, 23S, 23X) .
- These demarcations may represent edges of the region of full-thickness gap-junctional dissociation which have been shown to coincide with the boundaries of the isthmus of the reentrant circuit 3 .
- the magnitude of electrical discontinuity is great (i.e., where there is an abrupt spatial transition) the magnitude of the effective axial resistivity is also large 7 .
- any block- line there during premature excitation from a particular stimulus site position would be anticipated to be less susceptible to transient electrical properties, and therefore highly reproducible during repetitive episodes, as was observed.
- block of the activation wave-front along one line during the premature excitation cycle, followed by bifurcation of the wave-front and propagation around the arc tended to prevent block from occurring at the secondary line of discontinuity. This was likely due to the combined effects of: 1. the delay in arrival at the secondary location with a resulting increased time for recovery of excitability there, along with 2. coalescence of distinct wave-fronts arriving there from several directions rather than arrival of a coherent oncoming wave-front in a direction normal to the discontinuity.
- FIG. 22A it can be observed that activation of the border zone proceeds inward from all margins (LAD, base, apex, and lateral) but is most rapid from the base. This may suggest that the underlying substrate at the rapid location was potentially less abnormal than other areas of the border zone. Since healthy epicardial tissue is less refractory to premature stimulation 1 , a premature impulse originating from the basal margin for the experiment of FIGS. 22A-22I would be expected to most rapidly propagate inward at the infarct border zone as a large, cohesive wave-front, compared with stimulus sites positioned elsewhere in the border zone, which is essentially what was observed (compare FIG. 22E to FIGS. 22H-22I) .
- a relatively long, continuous unidirectional arc of conduction block must form as the result of premature stimulation for initiation of reentry.
- the wave-front then bifurcates and proceeds around it, traveling more slowly: 1. in the direction transverse to muscle fibers 1 ' 10 , 2. across any highly fractionated regions where there is dispersal of cells and zigzag conduction 10 , 3. at lines of electrical discontinuity where the effective axial resistivity is high 7 , and 4. within the area where the isthmus of the reentrant circuit forms, because gap- junctional interconnections have been disrupted and tend to conduct slowly when excited prematurely 3 .
- the reentry isthmus long axis could conceivably be aligned nearly transverse to muscle fibers (i.e., negligible contribution of factor 1, nonuniform anisotropic conduction 1 ' 10 , for reentry induction) as has been observed in approximately 15% of canine infarct experiments with monomorphic reentrant circuits 2 .
- factors 1-4 also act to slow conduction when the premature stimulation site is within the area where the isthmus actually forms (center stimulation as in FIGS.
- Electrogram duration measurements were made using an arbitrary amplitude threshold to delineate the contiguous time interval associated with local activation. Use of a different threshold could alter the precise locations of regions with differing electrogram duration. Corroborating histologic analyses would be useful in future studies to correlate electrical activity, as measured by quantification of electrogram shape, to presence of abnormal cellular coupling.
- Wit AL Janse MJ. Basic mechanisms of arrhythmias. In: Wit AL and Janse MJ, eds. The ventricular arrhythmias of ischemia and infarction . New York, NY: Futura; 1993:1-160.
- Ciaccio EJ Costeas CA, Coromilas J et al. Static relationship of cycle-length to reentrant circuit geometry. Circulation, 2001; 104:1946-1951.
- Ciaccio EJ Tosti AC, Scheinman MM. Relationship between sinus rhythm activation and the reentrant ventricular tachycardia isthmus. Circulation 2001; 104 : 613-619.
- Ciaccio EJ Dynamic relationship of cycle length to reentrant circuit geometry and to the slow conduction zone during ventricular tachycardia. Circulation, 2001; 103:1017-1024.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2002355738A AU2002355738A1 (en) | 2001-07-30 | 2002-07-30 | System and method for determining reentrant ventricular tachycardia isthmus location and shape for catheter ablation |
US10/485,676 US7245962B2 (en) | 2001-07-30 | 2002-07-30 | System and method for determining reentrant ventricular tachycardia isthmus location and shape for catheter ablation |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/918,216 US6847839B2 (en) | 2001-07-30 | 2001-07-30 | System and method for determining reentrant ventricular tachycardia isthmus location and shape for catheter ablation |
US09/918,216 | 2001-07-30 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2003011112A2 true WO2003011112A2 (en) | 2003-02-13 |
WO2003011112A3 WO2003011112A3 (en) | 2003-12-11 |
Family
ID=25439999
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2002/024130 WO2003011112A2 (en) | 2001-07-30 | 2002-07-30 | System and method for determining reentrant ventricular tachycardia isthmus location and shape for catheter ablation |
Country Status (3)
Country | Link |
---|---|
US (2) | US6847839B2 (en) |
AU (1) | AU2002355738A1 (en) |
WO (1) | WO2003011112A2 (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8521266B2 (en) | 2008-10-09 | 2013-08-27 | The Regents Of The University Of California | Methods for the detection and/or diagnosis of biological rhythm disorders |
US8676303B2 (en) | 2008-05-13 | 2014-03-18 | The Regents Of The University Of California | Methods and systems for treating heart instability |
US9468387B2 (en) | 2011-05-02 | 2016-10-18 | The Regents Of The University Of California | System and method for reconstructing cardiac activation information |
US9668666B2 (en) | 2011-05-02 | 2017-06-06 | The Regents Of The University Of California | System and method for reconstructing cardiac activation information |
CN108338786A (en) * | 2017-01-25 | 2018-07-31 | 韦伯斯特生物官能(以色列)有限公司 | Method and system for eliminating wide scope cardiac conditions |
US10058262B2 (en) | 2011-12-09 | 2018-08-28 | The Regents Of The University Of California | System and method of identifying sources for biological rhythms |
US10085655B2 (en) | 2013-03-15 | 2018-10-02 | The Regents Of The University Of California | System and method to define drivers of sources associated with biological rhythm disorders |
CN108903935A (en) * | 2018-07-11 | 2018-11-30 | 上海夏先机电科技发展有限公司 | A kind of ventricular premature beat recognition methods, identifying system and electronic equipment |
US10434319B2 (en) | 2009-10-09 | 2019-10-08 | The Regents Of The University Of California | System and method of identifying sources associated with biological rhythm disorders |
US10485438B2 (en) | 2011-05-02 | 2019-11-26 | The Regents Of The University Of California | System and method for targeting heart rhythm disorders using shaped ablation |
US10888379B2 (en) | 2017-01-25 | 2021-01-12 | Biosense Webster (Israel) Ltd. | Analyzing and mapping ECG signals and determining ablation points to eliminate brugada syndrome |
US10893819B2 (en) | 2017-01-25 | 2021-01-19 | Biosense Webster (Israel) Ltd. | Analyzing and mapping ECG signals and determining ablation points to eliminate Brugada syndrome |
Families Citing this family (114)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7519416B2 (en) * | 2002-02-04 | 2009-04-14 | Heartview, Llc | Diagnostic method utilizing standard lead ECG signals |
WO2005008418A2 (en) * | 2003-07-11 | 2005-01-27 | C.R. Bard, Inc. | Multi-color overlay system for processing and displaying electrocardiac signals |
US7787946B2 (en) | 2003-08-18 | 2010-08-31 | Cardiac Pacemakers, Inc. | Patient monitoring, diagnosis, and/or therapy systems and methods |
US8002553B2 (en) | 2003-08-18 | 2011-08-23 | Cardiac Pacemakers, Inc. | Sleep quality data collection and evaluation |
US20060247693A1 (en) | 2005-04-28 | 2006-11-02 | Yanting Dong | Non-captured intrinsic discrimination in cardiac pacing response classification |
US8521284B2 (en) | 2003-12-12 | 2013-08-27 | Cardiac Pacemakers, Inc. | Cardiac response classification using multisite sensing and pacing |
US7774064B2 (en) | 2003-12-12 | 2010-08-10 | Cardiac Pacemakers, Inc. | Cardiac response classification using retriggerable classification windows |
US20050288599A1 (en) * | 2004-05-17 | 2005-12-29 | C.R. Bard, Inc. | High density atrial fibrillation cycle length (AFCL) detection and mapping system |
US7706866B2 (en) | 2004-06-24 | 2010-04-27 | Cardiac Pacemakers, Inc. | Automatic orientation determination for ECG measurements using multiple electrodes |
US7805185B2 (en) | 2005-05-09 | 2010-09-28 | Cardiac Pacemakers, In. | Posture monitoring using cardiac activation sequences |
US7917196B2 (en) | 2005-05-09 | 2011-03-29 | Cardiac Pacemakers, Inc. | Arrhythmia discrimination using electrocardiograms sensed from multiple implanted electrodes |
US7509170B2 (en) | 2005-05-09 | 2009-03-24 | Cardiac Pacemakers, Inc. | Automatic capture verification using electrocardiograms sensed from multiple implanted electrodes |
US7457664B2 (en) | 2005-05-09 | 2008-11-25 | Cardiac Pacemakers, Inc. | Closed loop cardiac resynchronization therapy using cardiac activation sequence information |
US7890159B2 (en) | 2004-09-30 | 2011-02-15 | Cardiac Pacemakers, Inc. | Cardiac activation sequence monitoring and tracking |
US7797036B2 (en) | 2004-11-30 | 2010-09-14 | Cardiac Pacemakers, Inc. | Cardiac activation sequence monitoring for ischemia detection |
US20060122481A1 (en) * | 2004-11-22 | 2006-06-08 | Crispian Lee Sievenpiper | System and method for location based remote services |
US7996072B2 (en) | 2004-12-21 | 2011-08-09 | Cardiac Pacemakers, Inc. | Positionally adaptable implantable cardiac device |
US7715627B2 (en) * | 2005-03-25 | 2010-05-11 | Siemens Medical Solutions Usa, Inc. | Automatic determination of the standard cardiac views from volumetric data acquisitions |
US7392086B2 (en) | 2005-04-26 | 2008-06-24 | Cardiac Pacemakers, Inc. | Implantable cardiac device and method for reduced phrenic nerve stimulation |
US8242170B2 (en) * | 2005-06-06 | 2012-08-14 | The Regents Of The University Of California | Use of cis-epoxyeicosatrienoic acids and inhibitors of soluble epoxide hydrolase to reduce cardiomyopathy |
US8583220B2 (en) * | 2005-08-02 | 2013-11-12 | Biosense Webster, Inc. | Standardization of catheter-based treatment for atrial fibrillation |
US7590288B1 (en) * | 2005-11-07 | 2009-09-15 | Maxim Integrated Products, Inc. | Method and/or apparatus for detecting edges of blocks in an image processing system |
US20070118180A1 (en) | 2005-11-18 | 2007-05-24 | Quan Ni | Cardiac resynchronization therapy for improved hemodynamics based on disordered breathing detection |
US7515954B2 (en) * | 2006-06-13 | 2009-04-07 | Rhythmia Medical, Inc. | Non-contact cardiac mapping, including moving catheter and multi-beat integration |
US7505810B2 (en) * | 2006-06-13 | 2009-03-17 | Rhythmia Medical, Inc. | Non-contact cardiac mapping, including preprocessing |
US7729752B2 (en) * | 2006-06-13 | 2010-06-01 | Rhythmia Medical, Inc. | Non-contact cardiac mapping, including resolution map |
US8527048B2 (en) | 2006-06-29 | 2013-09-03 | Cardiac Pacemakers, Inc. | Local and non-local sensing for cardiac pacing |
US7580741B2 (en) | 2006-08-18 | 2009-08-25 | Cardiac Pacemakers, Inc. | Method and device for determination of arrhythmia rate zone thresholds using a probability function |
US8712507B2 (en) * | 2006-09-14 | 2014-04-29 | Cardiac Pacemakers, Inc. | Systems and methods for arranging and labeling cardiac episodes |
US8209013B2 (en) | 2006-09-14 | 2012-06-26 | Cardiac Pacemakers, Inc. | Therapeutic electrical stimulation that avoids undesirable activation |
US7776003B2 (en) * | 2006-10-28 | 2010-08-17 | Alois Zauner | Multimodal catheter for focal brain monitoring and ventriculostomy |
US7941208B2 (en) | 2006-11-29 | 2011-05-10 | Cardiac Pacemakers, Inc. | Therapy delivery for identified tachyarrhythmia episode types |
US7907994B2 (en) | 2007-01-11 | 2011-03-15 | Biosense Webster, Inc. | Automated pace-mapping for identification of cardiac arrhythmic conductive pathways and foci |
US20080190438A1 (en) * | 2007-02-08 | 2008-08-14 | Doron Harlev | Impedance registration and catheter tracking |
US8386014B2 (en) * | 2007-06-21 | 2013-02-26 | The Trustees Of Columbia University In The City Of New York | Systems and methods for implementing heart geometrical measurements |
US9037239B2 (en) | 2007-08-07 | 2015-05-19 | Cardiac Pacemakers, Inc. | Method and apparatus to perform electrode combination selection |
US8265736B2 (en) | 2007-08-07 | 2012-09-11 | Cardiac Pacemakers, Inc. | Method and apparatus to perform electrode combination selection |
US8103327B2 (en) | 2007-12-28 | 2012-01-24 | Rhythmia Medical, Inc. | Cardiac mapping catheter |
EP2254661B1 (en) | 2008-02-14 | 2015-10-07 | Cardiac Pacemakers, Inc. | Apparatus for phrenic stimulation detection |
US8538509B2 (en) | 2008-04-02 | 2013-09-17 | Rhythmia Medical, Inc. | Intracardiac tracking system |
EP2349467B1 (en) | 2008-10-06 | 2017-08-23 | Cardiac Pacemakers, Inc. | Dynamic cardiac resynchronization therapy by tracking intrinsic conduction |
US8137343B2 (en) | 2008-10-27 | 2012-03-20 | Rhythmia Medical, Inc. | Tracking system using field mapping |
EP2348979B1 (en) * | 2008-11-07 | 2019-10-30 | Cardioinsight Technologies, Inc. | Visualization of physiological data for virtual electrodes |
US8475445B2 (en) * | 2008-12-01 | 2013-07-02 | Daniel Soroff | Spectral analysis of intracardiac electrograms to predict identification of radiofrequency ablation sites |
US9398862B2 (en) | 2009-04-23 | 2016-07-26 | Rhythmia Medical, Inc. | Multi-electrode mapping system |
US8571647B2 (en) * | 2009-05-08 | 2013-10-29 | Rhythmia Medical, Inc. | Impedance based anatomy generation |
US8103338B2 (en) | 2009-05-08 | 2012-01-24 | Rhythmia Medical, Inc. | Impedance based anatomy generation |
US10398326B2 (en) | 2013-03-15 | 2019-09-03 | The Regents Of The University Of California | System and method of identifying sources associated with biological rhythm disorders |
US8700140B2 (en) | 2010-04-08 | 2014-04-15 | The Regents Of The University Of California | Methods, system and apparatus for the detection, diagnosis and treatment of biological rhythm disorders |
US8452404B1 (en) * | 2009-11-24 | 2013-05-28 | Angel Medical Systems, Inc. | Ischemia detection systems for paced-patients having three different detection modes |
US9381363B2 (en) * | 2009-12-07 | 2016-07-05 | Pacesetter, Inc. | Optimal pacing configuration via ventricular conduction delays |
US20110213260A1 (en) * | 2010-02-26 | 2011-09-01 | Pacesetter, Inc. | Crt lead placement based on optimal branch selection and optimal site selection |
US8694074B2 (en) | 2010-05-11 | 2014-04-08 | Rhythmia Medical, Inc. | Electrode displacement determination |
US8428700B2 (en) | 2011-01-13 | 2013-04-23 | Rhythmia Medical, Inc. | Electroanatomical mapping |
US9002442B2 (en) | 2011-01-13 | 2015-04-07 | Rhythmia Medical, Inc. | Beat alignment and selection for cardiac mapping |
US8897516B2 (en) | 2011-03-16 | 2014-11-25 | Biosense Webster (Israel) Ltd. | Two-dimensional cardiac mapping |
US9107600B2 (en) | 2011-05-02 | 2015-08-18 | The Regents Of The University Of California | System and method for reconstructing cardiac activation information |
US9713432B2 (en) * | 2011-05-31 | 2017-07-25 | Cardiac Pacemakers, Inc. | Wide QRS detector |
US10149626B1 (en) * | 2011-08-27 | 2018-12-11 | American Medical Technologies, Llc | Methods and systems for mapping and ablation of cardiac arrhythmias comprising atrial flutter |
US10827977B2 (en) | 2012-05-21 | 2020-11-10 | Kardium Inc. | Systems and methods for activating transducers |
US9198592B2 (en) | 2012-05-21 | 2015-12-01 | Kardium Inc. | Systems and methods for activating transducers |
US9017321B2 (en) | 2012-05-21 | 2015-04-28 | Kardium, Inc. | Systems and methods for activating transducers |
US8715199B1 (en) | 2013-03-15 | 2014-05-06 | Topera, Inc. | System and method to define a rotational source associated with a biological rhythm disorder |
GB201307211D0 (en) * | 2013-04-22 | 2013-05-29 | Imp Innovations Ltd | Image display interfaces |
US20140330270A1 (en) * | 2013-05-03 | 2014-11-06 | William J. Anderson | Method of ablating scar tissue to orient electrical current flow |
US9636032B2 (en) | 2013-05-06 | 2017-05-02 | Boston Scientific Scimed Inc. | Persistent display of nearest beat characteristics during real-time or play-back electrophysiology data visualization |
US9918649B2 (en) | 2013-05-14 | 2018-03-20 | Boston Scientific Scimed Inc. | Representation and identification of activity patterns during electro-physiology mapping using vector fields |
EP2996554B1 (en) * | 2013-05-17 | 2023-08-30 | University Health Network | System for decrement evoked potential (deep) mapping to identify critical components of the arrythmogenic circuit in cardiac arrhythmias |
US9427168B2 (en) | 2013-05-22 | 2016-08-30 | Aftx, Inc. | Methods, systems, and apparatus for identification, characterization, and treatment of rotors associated with fibrillation |
WO2015027191A1 (en) * | 2013-08-22 | 2015-02-26 | Cardionxt, Inc. | Methods, systems, and apparatus for identification and characterization of rotors associated with atrial fibrillation |
US9642674B2 (en) | 2013-09-12 | 2017-05-09 | Biosense Webster (Israel) Ltd. | Method for mapping ventricular/atrial premature beats during sinus rhythm |
US9687166B2 (en) | 2013-10-14 | 2017-06-27 | Boston Scientific Scimed, Inc. | High resolution cardiac mapping electrode array catheter |
US9380953B2 (en) | 2014-01-29 | 2016-07-05 | Biosense Webster (Israel) Ltd. | Hybrid bipolar/unipolar detection of activation wavefront |
JP6288676B2 (en) * | 2014-05-29 | 2018-03-07 | 富士通株式会社 | Visualization device, visualization method, and visualization program |
JP2017522923A (en) | 2014-06-03 | 2017-08-17 | ボストン サイエンティフィック サイムド,インコーポレイテッドBoston Scientific Scimed,Inc. | Electrode assembly with atraumatic distal tip |
WO2015187430A2 (en) | 2014-06-04 | 2015-12-10 | Boston Scientific Scimed, Inc. | Electrode assembly |
US20160008342A1 (en) | 2014-06-16 | 2016-01-14 | The Regents Of The University Of California | Methods of improving cell-based therapy |
US20150367577A1 (en) * | 2014-06-19 | 2015-12-24 | Materialise N.V. | Use of multiple beam spot sizes for obtaining improved performance in optical additive manufacturing techniques |
US10980439B2 (en) | 2014-08-06 | 2021-04-20 | Biosense Webster (Israel) Ltd | Wavefront analysis based on ablation parameters |
US9955889B2 (en) | 2014-11-03 | 2018-05-01 | Biosense Webster (Israel) Ltd. | Registration maps using intra-cardiac signals |
US10368936B2 (en) | 2014-11-17 | 2019-08-06 | Kardium Inc. | Systems and methods for selecting, activating, or selecting and activating transducers |
US10722184B2 (en) | 2014-11-17 | 2020-07-28 | Kardium Inc. | Systems and methods for selecting, activating, or selecting and activating transducers |
US9833161B2 (en) | 2015-02-09 | 2017-12-05 | Biosense Webster (Israel) Ltd. | Basket catheter with far-field electrode |
FR3034548A1 (en) * | 2015-04-03 | 2016-10-07 | Univ De Lorraine | METHOD AND SYSTEM FOR IDENTIFYING ISTHMA IN THREE DIMENSIONAL CARTOGRAPHY |
US10758144B2 (en) | 2015-08-20 | 2020-09-01 | Boston Scientific Scimed Inc. | Flexible electrode for cardiac sensing and method for making |
EP3346915A4 (en) | 2015-09-07 | 2018-10-10 | Ablacon Inc. | Systems, devices, components and methods for detecting the locations of sources of cardiac rhythm disorders in a patient's heart |
CN108140265B (en) | 2015-09-26 | 2022-06-28 | 波士顿科学医学有限公司 | System and method for anatomical shell editing |
US10405766B2 (en) | 2015-09-26 | 2019-09-10 | Boston Scientific Scimed, Inc. | Method of exploring or mapping internal cardiac structures |
US10271758B2 (en) | 2015-09-26 | 2019-04-30 | Boston Scientific Scimed, Inc. | Intracardiac EGM signals for beat matching and acceptance |
WO2017053914A1 (en) | 2015-09-26 | 2017-03-30 | Boston Scientific Scimed Inc. | Multiple rhythm template monitoring |
US9949657B2 (en) * | 2015-12-07 | 2018-04-24 | Biosense Webster (Israel) Ltd. | Displaying multiple-activation areas on an electroanatomical map |
US10582894B2 (en) | 2016-01-14 | 2020-03-10 | Biosense Webster (Israel) Ltd. | Region of interest rotational activity pattern detection |
US10517496B2 (en) | 2016-01-14 | 2019-12-31 | Biosense Webster (Israel) Ltd. | Region of interest focal source detection |
US10314542B2 (en) | 2016-01-14 | 2019-06-11 | Biosense Webster (Israel) Ltd. | Identification of fractionated signals |
US10624554B2 (en) | 2016-01-14 | 2020-04-21 | Biosense Webster (Israel) Ltd. | Non-overlapping loop-type or spline-type catheter to determine activation source direction and activation source type |
US11006887B2 (en) | 2016-01-14 | 2021-05-18 | Biosense Webster (Israel) Ltd. | Region of interest focal source detection using comparisons of R-S wave magnitudes and LATs of RS complexes |
EP3452162A4 (en) * | 2016-05-04 | 2020-08-05 | John R. Bullinga, MD | Leads and methods for cardiac resynchronization therapy |
JP7093776B2 (en) * | 2017-01-13 | 2022-06-30 | セント・ジュード・メディカル,カーディオロジー・ディヴィジョン,インコーポレイテッド | Systems and Methods for Generating Premature Ventricular Contraction Electrophysiological Maps |
GB201706561D0 (en) | 2017-04-25 | 2017-06-07 | Imp Innovations Ltd | Systems and methods for treating cardiac arrhythmia |
JP6857885B2 (en) * | 2017-07-26 | 2021-04-14 | 富士通株式会社 | Designated device, control program and control method of designated device |
US11164371B2 (en) * | 2017-12-20 | 2021-11-02 | Biosense Webster (Israel) Ltd. | Marking a computerized model of a cardiac surface |
US11350867B2 (en) * | 2018-04-27 | 2022-06-07 | Duke University | Small-scale time delay and single-shot conduction velocity analysis and mapping for cardiac electrophysiology |
US11160481B2 (en) | 2018-08-22 | 2021-11-02 | Biosense Webster (Israel) Ltd. | Atrial fibrillation mapping using atrial fibrillation cycle length (AFCL) gradients |
US11006886B2 (en) * | 2018-12-20 | 2021-05-18 | Biosense Webster (Israel) Ltd. | Visualization of different cardiac rhythms using different timing-pattern displays |
WO2020152619A1 (en) * | 2019-01-23 | 2020-07-30 | Impulse Dynamics Nv | Discrimination of supraventricular tachycardias in combined ccm-icd device |
CN110930857B (en) * | 2019-05-31 | 2022-04-15 | 上海华兴数字科技有限公司 | Method and device for drawing scattered points |
US11116435B2 (en) | 2019-08-26 | 2021-09-14 | Biosense Webster (Israel) Ltd. | Automatic identification of a location of focal source in atrial fibrillation (AF) |
US20210059549A1 (en) | 2019-08-26 | 2021-03-04 | Biosense Webster (Israel) Ltd. | Error estimation of local activation times (lat) measured by multiple electrode catheter |
US11253183B2 (en) | 2019-10-16 | 2022-02-22 | Biosense Webster (Israel) Ltd. | Data reuse for filling in missing data points |
US11607272B2 (en) * | 2019-11-12 | 2023-03-21 | Biosense Webster (Israel) Ltd. | Visual route indication for activation clusters |
US11730413B2 (en) * | 2020-07-01 | 2023-08-22 | Biosense Webster (Israel) Ltd. | Analyzing multi-electrode catheter signals to determine electrophysiological (EP) wave propagation vector |
CN111863264B (en) * | 2020-07-27 | 2021-06-22 | 哈尔滨医科大学 | Method for constructing zero-X-ray mapping ventricular premature beat three-dimensional model by adopting hot spot radius tracking method |
IL293942A (en) | 2021-06-22 | 2023-01-01 | Biosense Webster Israel Ltd | Improving mapping resolution of electrophysiological (ep) wave propagating on the surface of patient heart |
US20230093600A1 (en) * | 2021-09-22 | 2023-03-23 | Biosense Webster (Israel) Ltd. | Finding a cardiac line of block using statistical analysis of activation wave velocity |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6236883B1 (en) * | 1999-02-03 | 2001-05-22 | The Trustees Of Columbia University In The City Of New York | Methods and systems for localizing reentrant circuits from electrogram features |
-
2001
- 2001-07-30 US US09/918,216 patent/US6847839B2/en not_active Expired - Fee Related
-
2002
- 2002-07-30 US US10/485,676 patent/US7245962B2/en not_active Expired - Fee Related
- 2002-07-30 AU AU2002355738A patent/AU2002355738A1/en not_active Abandoned
- 2002-07-30 WO PCT/US2002/024130 patent/WO2003011112A2/en not_active Application Discontinuation
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6236883B1 (en) * | 1999-02-03 | 2001-05-22 | The Trustees Of Columbia University In The City Of New York | Methods and systems for localizing reentrant circuits from electrogram features |
Cited By (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10136860B2 (en) | 2008-05-13 | 2018-11-27 | The Regents Of The University Of California | System for detecting and treating heart instability |
US8676303B2 (en) | 2008-05-13 | 2014-03-18 | The Regents Of The University Of California | Methods and systems for treating heart instability |
US10092196B2 (en) | 2008-10-09 | 2018-10-09 | The Regents Of The University Of California | Method for analysis of complex rhythm disorders |
US9955879B2 (en) | 2008-10-09 | 2018-05-01 | The Regents Of The University Of California | System for analysis of complex rhythm disorders |
US8521266B2 (en) | 2008-10-09 | 2013-08-27 | The Regents Of The University Of California | Methods for the detection and/or diagnosis of biological rhythm disorders |
US10434319B2 (en) | 2009-10-09 | 2019-10-08 | The Regents Of The University Of California | System and method of identifying sources associated with biological rhythm disorders |
US9468387B2 (en) | 2011-05-02 | 2016-10-18 | The Regents Of The University Of California | System and method for reconstructing cardiac activation information |
US9913615B2 (en) | 2011-05-02 | 2018-03-13 | The Regents Of The University Of California | System and method for reconstructing cardiac activation information |
US10485438B2 (en) | 2011-05-02 | 2019-11-26 | The Regents Of The University Of California | System and method for targeting heart rhythm disorders using shaped ablation |
US9668666B2 (en) | 2011-05-02 | 2017-06-06 | The Regents Of The University Of California | System and method for reconstructing cardiac activation information |
US10149622B2 (en) | 2011-05-02 | 2018-12-11 | The Regents Of The University Of California | System and method for reconstructing cardiac activation information |
US10058262B2 (en) | 2011-12-09 | 2018-08-28 | The Regents Of The University Of California | System and method of identifying sources for biological rhythms |
US10085655B2 (en) | 2013-03-15 | 2018-10-02 | The Regents Of The University Of California | System and method to define drivers of sources associated with biological rhythm disorders |
US11446506B2 (en) | 2013-03-15 | 2022-09-20 | The Regents Of The University Of California | System and method of identifying sources associated with biological rhythm disorders |
EP3354192A1 (en) * | 2017-01-25 | 2018-08-01 | Biosense Webster (Israel) Ltd. | A method and system for eliminating a broad range of cardiac conditions by analyzing intracardiac signals, providing a detailed map and determining potential ablation points |
CN108338786A (en) * | 2017-01-25 | 2018-07-31 | 韦伯斯特生物官能(以色列)有限公司 | Method and system for eliminating wide scope cardiac conditions |
US10888379B2 (en) | 2017-01-25 | 2021-01-12 | Biosense Webster (Israel) Ltd. | Analyzing and mapping ECG signals and determining ablation points to eliminate brugada syndrome |
US10893819B2 (en) | 2017-01-25 | 2021-01-19 | Biosense Webster (Israel) Ltd. | Analyzing and mapping ECG signals and determining ablation points to eliminate Brugada syndrome |
US10952793B2 (en) | 2017-01-25 | 2021-03-23 | Biosense Webster (Israel) Ltd. | Method and system for eliminating a broad range of cardiac conditions by analyzing intracardiac signals providing a detailed map and determining potential ablation points |
US11819281B2 (en) | 2017-01-25 | 2023-11-21 | Biosense Webster (Israel) Ltd. | Analyzing and mapping ECG signals and determining ablation points to eliminate Brugada syndrome |
US11844614B2 (en) | 2017-01-25 | 2023-12-19 | Biosense Webster (Israel) Ltd. | Analyzing and mapping ECG signals and determining ablation points to eliminate Brugada syndrome |
CN108903935A (en) * | 2018-07-11 | 2018-11-30 | 上海夏先机电科技发展有限公司 | A kind of ventricular premature beat recognition methods, identifying system and electronic equipment |
CN108903935B (en) * | 2018-07-11 | 2021-06-25 | 上海夏先机电科技发展有限公司 | Ventricular premature beat identification method and system and electronic equipment |
Also Published As
Publication number | Publication date |
---|---|
US20040243012A1 (en) | 2004-12-02 |
AU2002355738A1 (en) | 2003-02-17 |
WO2003011112A3 (en) | 2003-12-11 |
US6847839B2 (en) | 2005-01-25 |
US7245962B2 (en) | 2007-07-17 |
US20030023130A1 (en) | 2003-01-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7245962B2 (en) | System and method for determining reentrant ventricular tachycardia isthmus location and shape for catheter ablation | |
US10842572B1 (en) | Methods, systems, and apparatuses for tracking ablation devices and generating lesion lines | |
US11278228B2 (en) | Identification and visualization of cardiac activation sequence in multi-channel recordings | |
US9655535B2 (en) | System and method for targeting heart rhythm disorders using shaped ablation | |
US8386014B2 (en) | Systems and methods for implementing heart geometrical measurements | |
Lin et al. | Radiofrequency catheter ablation of ventricular arrhythmias originating from the continuum between the aortic sinus of Valsalva and the left ventricular summit: electrocardiographic characteristics and correlative anatomy | |
US11571160B2 (en) | Methods and systems for wavelength mapping cardiac fibrillation and optimizing ablation lesion placement | |
Ciaccio et al. | Structure and function of the ventricular tachycardia isthmus | |
WO2012047563A1 (en) | Method for determining the location of regions in tissue relevant to electrical propagation | |
CN107049471B (en) | Non-overlapping ring or spline type catheter for determining activation source direction and activation source type | |
CN111657932A (en) | Devices, systems, and uses of catheter systems for mapping and recording heart rhythm | |
Roney et al. | Challenges associated with interpreting mechanisms of AF | |
Campbell et al. | Updates in ventricular tachycardia ablation | |
Ciaccio et al. | Detection of the diastolic pathway, circuit morphology, and inducibility of human postinfarction ventricular tachycardia from mapping in sinus rhythm | |
Ciaccio et al. | Slow uniform electrical activation during sinus rhythm is an indicator of reentrant VT isthmus location and orientation in an experimental model of myocardial infarction | |
Campos et al. | Characterizing the clinical implementation of a novel activation-repolarization metric to identify targets for catheter ablation of ventricular tachycardias using computational models | |
CA3121576A1 (en) | Methods and systems for wavelength mapping cardiac fibrillation and optimizing ablation lesion placement | |
Steven et al. | Mapping of atrial tachycardias after catheter ablation for atrial fibrillation: use of bi-atrial activation patterns to facilitate recognition of origin | |
US11179086B2 (en) | Automated electroanatomical annotation of positive entrainment sites for mapping of active reentrant circuits | |
Packer et al. | Imaging of the cardiac and thoracic veins | |
Lee et al. | Noncontact three-dimensional mapping guides catheter ablation of difficult atrioventricular nodal reentrant tachycardia | |
Ehnesh | Spatiotemporal behaviour of AF drivers in patients with persistent atrial fibrillation using non-contacting intracardiac atrial electrograms | |
Blendea et al. | Intraatrial conduction block in the right posteroseptal region after failed accessory pathway ablation—Importance of delineation of three-dimensional pathway geometry | |
Feld et al. | Ablation of Cavotricuspid Isthmus–Dependent Atrial Flutters | |
Pavlova | Radiofrequency catheter Ablation |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A2 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BY BZ CA CH CN CO CR CU CZ DE DM DZ EC EE ES FI GB GD GE GH HR HU ID IL IN IS JP KE KG KP KR LC LK LR LS LT LU LV MA MD MG MN MW MX MZ NO NZ OM PH PL PT RU SD SE SG SI SK SL TJ TM TN TR TZ UA UG US UZ VN YU ZA ZM Kind code of ref document: A2 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG US UZ VN YU ZA ZM ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A2 Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LU MC NL PT SE SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG Kind code of ref document: A2 Designated state(s): GH GM KE LS MW MZ SD SL SZ UG ZM ZW AM AZ BY KG KZ RU TJ TM AT BE BG CH CY CZ DK EE ES FI FR GB GR IE IT LU MC PT SE SK TR BF BJ CF CG CI GA GN GQ GW ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
WWE | Wipo information: entry into national phase |
Ref document number: 10485676 Country of ref document: US |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
122 | Ep: pct application non-entry in european phase | ||
NENP | Non-entry into the national phase |
Ref country code: JP |
|
WWW | Wipo information: withdrawn in national office |
Country of ref document: JP |