WO2009070079A1 - An active fixation helix and a medical implantable lead - Google Patents

An active fixation helix and a medical implantable lead Download PDF

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Publication number
WO2009070079A1
WO2009070079A1 PCT/SE2008/000639 SE2008000639W WO2009070079A1 WO 2009070079 A1 WO2009070079 A1 WO 2009070079A1 SE 2008000639 W SE2008000639 W SE 2008000639W WO 2009070079 A1 WO2009070079 A1 WO 2009070079A1
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WO
WIPO (PCT)
Prior art keywords
helix
wire
active fixation
lead
cross sectional
Prior art date
Application number
PCT/SE2008/000639
Other languages
French (fr)
Inventor
Rolf Hill
Olof Stegfeldt
Per E. Jarl
Original Assignee
St. Jude Medical Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by St. Jude Medical Ab filed Critical St. Jude Medical Ab
Publication of WO2009070079A1 publication Critical patent/WO2009070079A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/056—Transvascular endocardial electrode systems
    • A61N1/057—Anchoring means; Means for fixing the head inside the heart
    • A61N1/0573—Anchoring means; Means for fixing the head inside the heart chacterised by means penetrating the heart tissue, e.g. helix needle or hook

Definitions

  • the present invention relates to an active fixation helix for use as a tissue attaching element of a medical implantable lead and which is formed of a helix wire, defining an inner diameter space confined by helix windings.
  • the invention also relates to a medical implantable lead being adapted to be inserted into a human or animal body and attached to an organ inside the body for monitoring and/or controlling the function of the organ, comprising an active fixation helix in its distal end which is adapted to function as an attachment by being screwed into the tissue of the organ and which is formed of a helix wire, defining an inner diameter space confined by helix windings.
  • Helixes and medical implantable leads containing such helixes are well known in the art and are used to monitor and/or control the function of an organ inside a human or animal body, e.g. to monitor and pace the activity of a heart by means of a pacemaker.
  • the helix is used to actively fixate the lead to the organ by being screwed into the tissue.
  • the helix can be stationary attached to the lead, in which case the entire lead is rotated when attaching to the organ.
  • the helix can also be rotatably but unextendably attached to the lead, in which case the helix is rotated in relation to the lead by means of an inner coil or a stylet inside the lead.
  • the helix can be rotatably as well as extendably attached to the lead and in an initial stage accommodated inside a header sleeve in a distal end of the lead, in which case the helix is rotated and at the same time extended out from the header sleeve, likewise by means of an inner coil or a stylet inside the lead.
  • the development in the art goes towards decreasing dimensions of the equipment used and accordingly also of the leads, which are becoming thinner. This has to effect that also the helix, which besides being utilized as an active fixation member also can function as an electrode in the organ, will be- come diminished with deteriorated mechanical and electrical function as a result.
  • the helix is manufactured of a thin wire, which is formed in a helical shape such that the helix presents an outer diameter and an inner diameter defining a free inner space inside the helix.
  • the outer diameter of the helix has to be decreased in order to adapt the helix to the lead or to find room for it inside a header sleeve in the lead.
  • the free inner space inside the inner diameter of the helix is often used to accommodate a steroid plug in order to prevent inflammation in the wound caused by penetration of the helix into the organ. Accordingly, it is not advisable to decrease the free inner space to much, which will lead to that also the dimension of the helix wire will be decreased as the outer diameter of the helix is decreased.
  • the helix is formed of a helix wire having a circular cross section.
  • a smaller wire diameter will generally lead to a better penetration ability, which is advantageous since in this way it will be easier to penetrate the organ.
  • a cardiac stimulation lead having a helix wire profile, which in cross section has a larger dimension in a direction in parallel to the longitudinal axis of the helix than in the radial direction of the helix.
  • the helix is constructed of a flat wire instead of one having a circular cross section. This is done to improve the helix visibility when monitoring the lead tip by means of x-ray examination when positioning and attaching the lead to a heart.
  • a helix wire profiled in this way will have a larger coring tendency than a wire of a circular cross section, since the spacing between each coil of the helix will be smaller, which will reduce the amount of tissue remaining between each coil, and the surfaces facing in a direction in parallel to the longitudinal axis of the helix will be smaller, i.e. sharper, and will therefore easier cut through the tissue when a pulling force is applied to the lead.
  • the object of the invention is to improve prior art active fixation helixes for medical implantable leads. More precisely, it is an object to provide a helix for a medical implantable lead, which provides improved properties for attachment to the tissue. At least this object is achieved by an active fixation helix according to claim 1.
  • the invention also relates to a medical implantable lead having essentially the same object as above. At least this object is achieved by a medical implantable lead according to claim 6.
  • the basis of the invention is the insight that the above object may be achieved by an active fixation helix, which is formed of a helix wire whose cross sectional dimension in a direction in parallel to the longitudinal axis of the helix is smaller than the cross sectional dimension in a direction transverse of the longitudinal axis.
  • the cross sectional shape of the helix wire may be generally flat, oval, triangular, C-shaped, D-shaped or any other suitable shape, as long as the helix wire has a smaller cross sectional dimension in a direction in parallel to the longitudinal axis of the helix than in a direction perpendicular thereto.
  • the fixating characteristics may be enhanced since the distance between each winding, at maintained winding pitch, will become larger having to effect that more tissue will be accommodated between each winding and the area of the helix wire facing in a direction in parallel to the longitudinal axis of the helix will be enlarged, which will reduce the risk of tearing the tissue when applying a pulling force in the lead.
  • the helix wire will also be more rigid against deflection in a plane transverse to the longitudinal axis of the helix in comparison to a helix wire of circular cross sec- tion and having the same cross sectional area. This is advantageous when screwing and penetrating the helix into the tissue.
  • the cur- rent density from the helix will be enhanced, which will improve the capability to overcome high current thresholds in the tissue and/or to reduce energy consumption.
  • the current density can be enhanced further by providing the helix wire with a cross sectional shape having a sharp edge facing outwards from the helix, e.g. as a triangular shape having one apex facing outwards.
  • the ability for the helix wire to drain blood from the wound, caused by screwing the helix into the tissue, will be enhanced.
  • Such a feature may be important to prevent or reduce high acute electrical threshold during the days or weeks immediately after mounting of the helix into the tissue.
  • a fixation helix of a helix wire having a smaller dimension in parallel to the longitudinal axis of the helix will also give a higher flexibility along the longitudinal direction of the helix, i.e. more flexible for deflection in a plane being parallel to the longitudinal axis of the helix. This is advantageous when the helix is attached in an essentially horizontal direction, since then the lead may hang downwards from the helix by deflection in the helix, which will relief strains from the attachment in the tissue since the lead will not stand rigidly straight out from the tissue.
  • One further advantage with a helix wire having a more "flat" cross sec- tional shape is that the tip of the helix can be more easily grinded, in order to facilitate penetration into the tissue.
  • grinding a helix wire having a circular cross sectional shape it is often necessary to perform the grinding in three different planes.
  • Fig 1 is a perspective view of a distal portion of a medical implantable lead having a helix retracted and accommodated inside a header sleeve;
  • Fig 2 is a perspective view according to fig 1 but with the helix projecting from the header sleeve;
  • Fig 3-6 plan views as well as cross sections of different embodiments of helixes formed of helix wires having different cross sectional shapes
  • Fig 7 graphs showing the resulting current density around a prior art helix having a circular cross section in comparison to helixes designed according to the invention having a triangular and an oval cross sectional form, respectively.
  • figs 1 and 2 in which are illustrated, in perspective views, the distal portion of a medical implantable lead 1.
  • the illus- trated lead is of the kind having an active fixation helix 2, which in an initial stage is retracted and accommodated in a hollow header sleeve 3, as is illustrated in fig 1.
  • the lead is highly flexible except for the distal header sleeve 3 which is rigid.
  • the helix 2 is screwed out from the distal end of the lead, it will also be screwed into the tissue and thereby attach the distal end of the medical im- plantable lead to the organ.
  • helixes 2 having different profiled helix wires 4 in plan views as well as cross sectional views.
  • One common feature of all these helix wires is that the cross sectional dimension of the helix wire 4 is smaller in a direction x in parallel to the longitudinal axis of each helix than in a direction y transverse to the axis of the helix.
  • the x- and y-directions are indicated by the coordinate axis above the figs 3-6.
  • the helix wire 4 has an oval shape in cross section and has its largest cross sectional dimension oriented in the direction y transverse to the longitudinal axis of the helix 2, whereas the smallest cross sectional dimension of the oval is oriented in the direction x in parallel to the longitudinal axis.
  • Fig 4 illustrates a helix 2 having an essentially flat shape in cross sec- tion. More precisely, the helix wire is formed with opposite plan surfaces facing in the direction x in parallel to the longitudinal axis of the helix and rounded edges facing in the direction y transverse to the longitudinal axis of the helix.
  • the helix illustrated in fig 5 is somewhat C-shaped in cross section having a convex surface and an opposed concave surface, which are facing in the direction x in parallel to the longitudinal axis of the helix.
  • the concave surface forms a groove 5 along the helix wire which is beneficial in so far as it facilitates draining of blood from the tissue caused by screwing in of the helix 2 when attaching the medical implantable lead.
  • fig 6 illustrates a helix wire being triangular in cross section.
  • the triangle is not an equilateral triangle but instead the triangle has a larger height in the direction y transverse of the longitudinal axis of the helix, whereas the smaller base is in the direction x in parallel to the longitudinal axis of the helix. Accordingly, the triangle forms an apex 6 directed outwards from the helix.
  • the shape of the helix wire according to the invention is advantageous when using the helix as an active electrode inside the tissue.
  • the cross sectional shapes of the helix which have been simulated is a prior art standard helix having a circular cross sectional shape 7, a helix according to the invention having an oval cross sectional shape 8 and a helix according to the invention having a triangular cross sectional shape 9.
  • the helixes having a cross sectional shape according to the invention have a higher current den- sity in a region from the surface of the helix to distance about 200 ⁇ m from the helix surface.
  • the helixes according to the invention have about 65%, at 50 ⁇ m about 37% and at 100 ⁇ about 23% higher current density than the prior art helix having a circular cross sectional shape. This is advantageous since it means that the capability to overcome high current thresholds in the tissue and/or to reduce energy consumption will be improved.
  • the thickness of the fibrous tissue around implanted helixes can be further reduced by improved technology, such as new materials in surface layers and the like, in which case the im- provement of the current density achieved by the present invention will be further increased.

Abstract

The invention relates to an active fixation helix (2) for use as a tissue attaching element of a medical implantable lead and which is formed of a he- Nx wire (4), defining an inner diameter space confined by helix windings. The cross sectional dimension of the helix wire (4) is smaller in a direction in parallel to the longitudinal axis of the lead than in a direction transverse of the longitudinal axis of the lead. The invention also relates to a medical implantable lead comprising such an active fixation helix.

Description

AN ACTIVE FIXATION HELIX AND A MEDICAL IMPLANTABLE LEAD
The present invention relates to an active fixation helix for use as a tissue attaching element of a medical implantable lead and which is formed of a helix wire, defining an inner diameter space confined by helix windings.
The invention also relates to a medical implantable lead being adapted to be inserted into a human or animal body and attached to an organ inside the body for monitoring and/or controlling the function of the organ, comprising an active fixation helix in its distal end which is adapted to function as an attachment by being screwed into the tissue of the organ and which is formed of a helix wire, defining an inner diameter space confined by helix windings.
Background of the invention
Helixes and medical implantable leads containing such helixes according to the introductory part, are well known in the art and are used to monitor and/or control the function of an organ inside a human or animal body, e.g. to monitor and pace the activity of a heart by means of a pacemaker. The helix is used to actively fixate the lead to the organ by being screwed into the tissue. The helix can be stationary attached to the lead, in which case the entire lead is rotated when attaching to the organ. The helix can also be rotatably but unextendably attached to the lead, in which case the helix is rotated in relation to the lead by means of an inner coil or a stylet inside the lead. Finally, the helix can be rotatably as well as extendably attached to the lead and in an initial stage accommodated inside a header sleeve in a distal end of the lead, in which case the helix is rotated and at the same time extended out from the header sleeve, likewise by means of an inner coil or a stylet inside the lead.
The development in the art goes towards decreasing dimensions of the equipment used and accordingly also of the leads, which are becoming thinner. This has to effect that also the helix, which besides being utilized as an active fixation member also can function as an electrode in the organ, will be- come diminished with deteriorated mechanical and electrical function as a result. The helix is manufactured of a thin wire, which is formed in a helical shape such that the helix presents an outer diameter and an inner diameter defining a free inner space inside the helix.
As the dimensions of the medical implantable leads are decreasing, also the outer diameter of the helix has to be decreased in order to adapt the helix to the lead or to find room for it inside a header sleeve in the lead. The free inner space inside the inner diameter of the helix is often used to accommodate a steroid plug in order to prevent inflammation in the wound caused by penetration of the helix into the organ. Accordingly, it is not advisable to decrease the free inner space to much, which will lead to that also the dimension of the helix wire will be decreased as the outer diameter of the helix is decreased.
Normally, in prior art, the helix is formed of a helix wire having a circular cross section. A smaller wire diameter will generally lead to a better penetration ability, which is advantageous since in this way it will be easier to penetrate the organ.
From US 7162310 is known a cardiac stimulation lead having a helix wire profile, which in cross section has a larger dimension in a direction in parallel to the longitudinal axis of the helix than in the radial direction of the helix. I.e. the helix is constructed of a flat wire instead of one having a circular cross section. This is done to improve the helix visibility when monitoring the lead tip by means of x-ray examination when positioning and attaching the lead to a heart. However, a helix wire profiled in this way will have a larger coring tendency than a wire of a circular cross section, since the spacing between each coil of the helix will be smaller, which will reduce the amount of tissue remaining between each coil, and the surfaces facing in a direction in parallel to the longitudinal axis of the helix will be smaller, i.e. sharper, and will therefore easier cut through the tissue when a pulling force is applied to the lead.
When attaching a medical implantable lead to an organ by screwing a helix into the tissue, it will give rise to bleeding in the tissue. If, when utilizing the helix as an electrode, the blood from the wound can not escape from the tissue, it will cause a high acute electrical threshold, which will remain as long as coagulated or liquid blood is present around the helix and which will deteriorate the performance of the lead.
Summary of the invention The object of the invention is to improve prior art active fixation helixes for medical implantable leads. More precisely, it is an object to provide a helix for a medical implantable lead, which provides improved properties for attachment to the tissue. At least this object is achieved by an active fixation helix according to claim 1. The invention also relates to a medical implantable lead having essentially the same object as above. At least this object is achieved by a medical implantable lead according to claim 6.
Accordingly , the basis of the invention is the insight that the above object may be achieved by an active fixation helix, which is formed of a helix wire whose cross sectional dimension in a direction in parallel to the longitudinal axis of the helix is smaller than the cross sectional dimension in a direction transverse of the longitudinal axis.
Within this general idea, the invention may be modified in many different ways. For example, the cross sectional shape of the helix wire may be generally flat, oval, triangular, C-shaped, D-shaped or any other suitable shape, as long as the helix wire has a smaller cross sectional dimension in a direction in parallel to the longitudinal axis of the helix than in a direction perpendicular thereto.
By forming the helix according to the invention, several advantages may be achieved. For example, the fixating characteristics may be enhanced since the distance between each winding, at maintained winding pitch, will become larger having to effect that more tissue will be accommodated between each winding and the area of the helix wire facing in a direction in parallel to the longitudinal axis of the helix will be enlarged, which will reduce the risk of tearing the tissue when applying a pulling force in the lead. The helix wire will also be more rigid against deflection in a plane transverse to the longitudinal axis of the helix in comparison to a helix wire of circular cross sec- tion and having the same cross sectional area. This is advantageous when screwing and penetrating the helix into the tissue.
Moreover, when using the helix as an active electrode, since the cross sectional dimension facing outwards from the helix will be reduced, the cur- rent density from the helix will be enhanced, which will improve the capability to overcome high current thresholds in the tissue and/or to reduce energy consumption. The current density can be enhanced further by providing the helix wire with a cross sectional shape having a sharp edge facing outwards from the helix, e.g. as a triangular shape having one apex facing outwards. By providing the helix wire with a groove having a concavely formed surface in cross section, e.g. as with a C-formed helix wire, the ability for the helix wire to drain blood from the wound, caused by screwing the helix into the tissue, will be enhanced. Such a feature may be important to prevent or reduce high acute electrical threshold during the days or weeks immediately after mounting of the helix into the tissue.
A fixation helix of a helix wire having a smaller dimension in parallel to the longitudinal axis of the helix, will also give a higher flexibility along the longitudinal direction of the helix, i.e. more flexible for deflection in a plane being parallel to the longitudinal axis of the helix. This is advantageous when the helix is attached in an essentially horizontal direction, since then the lead may hang downwards from the helix by deflection in the helix, which will relief strains from the attachment in the tissue since the lead will not stand rigidly straight out from the tissue.
One further advantage with a helix wire having a more "flat" cross sec- tional shape, according to the invention, is that the tip of the helix can be more easily grinded, in order to facilitate penetration into the tissue. When grinding a helix wire having a circular cross sectional shape it is often necessary to perform the grinding in three different planes. However, when grinding a more flat shaped helix wire, it is often sufficient to grind the tip in only one or two planes. This will reduce the number of machining steps and machining time for each helix. Brief description of the drawings
Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings, in which: Fig 1 is a perspective view of a distal portion of a medical implantable lead having a helix retracted and accommodated inside a header sleeve;
Fig 2 is a perspective view according to fig 1 but with the helix projecting from the header sleeve;
Fig 3-6 plan views as well as cross sections of different embodiments of helixes formed of helix wires having different cross sectional shapes; and
Fig 7 graphs showing the resulting current density around a prior art helix having a circular cross section in comparison to helixes designed according to the invention having a triangular and an oval cross sectional form, respectively.
Detailed description of embodiments of the invention
Reference is first made to figs 1 and 2 in which are illustrated, in perspective views, the distal portion of a medical implantable lead 1. The illus- trated lead is of the kind having an active fixation helix 2, which in an initial stage is retracted and accommodated in a hollow header sleeve 3, as is illustrated in fig 1. The lead is highly flexible except for the distal header sleeve 3 which is rigid. When the medical implantable lead is inserted into a human or animal body and the distal end is positioned against the tissue of an organ inside the body, the helix can be projected by being screwed out from the header sleeve, as is illustrated in fig 2, by rotating the helix by means of e.g. a not shown inner coil or a stylet from the proximal end of the lead. At the same time as the helix 2 is screwed out from the distal end of the lead, it will also be screwed into the tissue and thereby attach the distal end of the medical im- plantable lead to the organ.
Reference is then made to figs 3 to 6, in which are illustrated helixes 2 having different profiled helix wires 4 in plan views as well as cross sectional views. One common feature of all these helix wires is that the cross sectional dimension of the helix wire 4 is smaller in a direction x in parallel to the longitudinal axis of each helix than in a direction y transverse to the axis of the helix. The x- and y-directions are indicated by the coordinate axis above the figs 3-6. In fig 3 the helix wire 4 has an oval shape in cross section and has its largest cross sectional dimension oriented in the direction y transverse to the longitudinal axis of the helix 2, whereas the smallest cross sectional dimension of the oval is oriented in the direction x in parallel to the longitudinal axis. Fig 4 illustrates a helix 2 having an essentially flat shape in cross sec- tion. More precisely, the helix wire is formed with opposite plan surfaces facing in the direction x in parallel to the longitudinal axis of the helix and rounded edges facing in the direction y transverse to the longitudinal axis of the helix.
The helix illustrated in fig 5 is somewhat C-shaped in cross section having a convex surface and an opposed concave surface, which are facing in the direction x in parallel to the longitudinal axis of the helix. The concave surface forms a groove 5 along the helix wire which is beneficial in so far as it facilitates draining of blood from the tissue caused by screwing in of the helix 2 when attaching the medical implantable lead. Finally, fig 6 illustrates a helix wire being triangular in cross section.
The triangle is not an equilateral triangle but instead the triangle has a larger height in the direction y transverse of the longitudinal axis of the helix, whereas the smaller base is in the direction x in parallel to the longitudinal axis of the helix. Accordingly, the triangle forms an apex 6 directed outwards from the helix. As mentioned before, the shape of the helix wire according to the invention is advantageous when using the helix as an active electrode inside the tissue.
In order to determine the efficiency of the suggested shape of the helix, the current density surrounding the helix has been simulated, with a predeter- mined current delivered to the helix electrode, for three different cross sectional shapes of the helix. The result of the simulation is presented in the graphs of fig 7. The cross sectional shapes of the helix which have been simulated, is a prior art standard helix having a circular cross sectional shape 7, a helix according to the invention having an oval cross sectional shape 8 and a helix according to the invention having a triangular cross sectional shape 9. As apparent from the graphs in fig 7, the helixes having a cross sectional shape according to the invention, have a higher current den- sity in a region from the surface of the helix to distance about 200 μm from the helix surface. At a distance of 25 μm from the helix surface, the helixes according to the invention have about 65%, at 50 μm about 37% and at 100μ about 23% higher current density than the prior art helix having a circular cross sectional shape. This is advantageous since it means that the capability to overcome high current thresholds in the tissue and/or to reduce energy consumption will be improved.
When implanting a helix into tissue, a layer of fibrous tissue will in the course of time be formed around the helix. However, such fibrous tissue is not excitable by means of electric current and, accordingly, the electric current has to reach beyond the fibrous tissue in order to excite the organ. Experiments performed by the present applicant, in which were measured the thickness of the fibrous tissue layer around helixes, having a surface layer of titanium nitride and being implanted into heart tissue of animals, revealed that the thickness of fibrous tissue typically is between about 12 to 30 μm, i.e. well within the distance from the helix surface where the current density is increased by means of a helix designed according to the present invention. Moreover, in the future it is not unlikely that the thickness of the fibrous tissue around implanted helixes can be further reduced by improved technology, such as new materials in surface layers and the like, in which case the im- provement of the current density achieved by the present invention will be further increased.
For a skilled man in the art it is obvious that the cross sectional shape of the helix wire can be modified in many different ways within the scope of the associated.claims and that the embodiments above are only exemplary.

Claims

1. An active fixation helix for use as a tissue attaching element of a medical implantable lead (1 ) and which is formed of a helix wire (4), defining an inner diameter space confined by helix windings, characterized in that the cross sectional dimension of the helix wire (4) is smaller in a direction (x) in parallel to the longitudinal axis of the lead than in a direction (y) transverse of the longitudinal axis of the lead.
2. An active fixation helix according to claim 1, characterized in that the cross sectional shape of the helix wire (4) includes at least one distinct edge (6) along the longitudinal extension of the wire.
3. An active fixation helix according to claim 2, characterized in that at least one distinct edge (6) is directed outwards in relation to the inner diameter space.
4. An active fixation helix according to any of the preceding claims, cha racterized in that the cross sectional shape of the helix wire (4) includes at least one groove formation (5) having a concavely shaped surface.
5. An active fixation helix according to any of the preceding claims, characterized in that the active fixation helix (2) is adapted to function- as an electrode inside the tissue.
6. A medical implantable lead being adapted to be inserted into a human or animal body and attached to an organ inside the body for monitoring and/or controlling the function of the organ, comprising an active fixation helix (2) in its distal end which is adapted to function as an attachment by being screwed into the tissue of the organ and which is formed of a helix wire (4), defining an inner diameter space confined by helix windings, characterize d in that the cross sectional dimension of the helix wire (4) is smaller in a direction (x) in parallel to the longitudinal axis of the active fixation helix than in a direction (y) transverse of the longitudinal axis of the active fixation helix (2).
7. A medical implantable lead according to claim 6, characterize d in that the cross sectional shape of the helix wire (4) includes at least one distinct edge (6) along the longitudinal extension of the helix wire.
8. A medical implantable lead according to claim 7, characteri- z e d in that at least one distinct edge (6) is directed outwards in relation to the inner diameter space.
9. A medical implantable lead according to any of the claims 6-8, cha racterized in that the cross sectional shape of the helix wire (4) includes at least one groove formation (5) having a concavely shaped surface.
10. A medical implantable lead according to any of the claims 6-9, characterized in that the active fixation helix (2) is adapted to function as an electrode inside the tissue.
PCT/SE2008/000639 2007-11-29 2008-11-12 An active fixation helix and a medical implantable lead WO2009070079A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SEPCT/SE2007/050924 2007-11-29
SE2007050924 2007-11-29

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5002067A (en) * 1989-08-23 1991-03-26 Medtronic, Inc. Medical electrical lead employing improved penetrating electrode
US5354327A (en) * 1993-04-07 1994-10-11 Medtronic, Inc. Conductor coil with specific ratio of torque to bending stiffness
US20060052770A1 (en) * 1998-07-07 2006-03-09 Medtronic, Inc. Helical needle apparatus for creating a virtual electrode used for the ablation of tissue
US20060247751A1 (en) * 2005-04-28 2006-11-02 Seifert Kevin R Guide catheters for accessing cardiac sites
US7204847B1 (en) * 2000-07-28 2007-04-17 C. R. Bard, Inc. Implant anchor systems

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5002067A (en) * 1989-08-23 1991-03-26 Medtronic, Inc. Medical electrical lead employing improved penetrating electrode
US5354327A (en) * 1993-04-07 1994-10-11 Medtronic, Inc. Conductor coil with specific ratio of torque to bending stiffness
US20060052770A1 (en) * 1998-07-07 2006-03-09 Medtronic, Inc. Helical needle apparatus for creating a virtual electrode used for the ablation of tissue
US7204847B1 (en) * 2000-07-28 2007-04-17 C. R. Bard, Inc. Implant anchor systems
US20060247751A1 (en) * 2005-04-28 2006-11-02 Seifert Kevin R Guide catheters for accessing cardiac sites

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