Medical electrical lead and introducer system for implantable pulse generator

• US 5,443,492 A
• Filed: 02/02/1994
• Issued: 08/22/1995
• Est. Priority Date: 02/02/1994
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: McVenes, Rick D., Stokes, Kenneth B., Proctor, Keith J.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US08/189,565
• Time in Patent Office: 566 Days
• Field of Search: 607/126-128, 607/131
• US Class Current: 607/131
• CPC Class Codes: A61N 1/0568 with drug delivery
• CPC Class Codes: A61N 1/0573 chacterised by means penetrating the heart tissue, e.g. helix needle or hook
• CPC Class Codes: A61N 2001/0578 having means for removal or extraction

Abstract

An implantable lead for establishing electrical contact between a medical device and body tissue, in which an active fixation mechanism secures the lead in place while allowing a distal electrode on the lead to mechanically "float" with respect to the body tissue. In one embodiment, the active fixation mechanism comprises a curved hook disposed on the lead at a point spaced proximally back from the distal end of the lead. The curved hook defines a helix around at least a portion of the lead'"'"'s circumference. A hollow introducer needle is slidably disposed on the lead. The hollow needle provided with a longitudinal slit in a distal section of is length, such that the distal section of the needle can be advanced over the distal end of the lead, past the fixation hook, which is received in the longitudinal slit. With the needle slid over the distal end of the lead, the needle is stabbed tangentially into an implant site, bringing the fixation hook proximal to the surface of the body tissue. Then, the needle is twisted (bringing about a twisting of the lead), causing the curved fixation hook to pierce and engage the body tissue, securing the lead in place. Then the needle is withdrawn from the body tissue and removed from the lead. In an alternative embodiment, the lead can be placed by an endocardial approach using a flexible cannula with a longitudinally slotted tip.

Claims

1. An implantable lead for establishing electrical contact between a medical device and body tissue, comprising:

an elongated lead body having proximal and distal ends and having at least one electrical conductor extending between said proximal and distal ends;

a terminal assembly disposed on said proximal end of said lead body;

an electrode assembly disposed proximate said distal end of said lead body, said electrode assembly including a first electrode, said first electrode electrically connected to said conductor;

a curved fixation hook disposed on said lead body, said curved fixation hook disposed at a point spaced back from said distal end of said lead and extends radially outward from said lead for a first distance and then coiling around at least a portion of said lead'"'"'s circumference.

2. A lead in accordance with claim 1, wherein said curved fixation hook extends radially outward from said lead body at a first angle with respect to a longitudinal axis of said lead body.

3. The lead in accordance with claim 2 wherein said first direction is less than ninety degrees.

4. A lead in accordance with claim 1, wherein said first electrode is disposed at the distal end of said lead body.

5. A lead in accordance with claim 1, wherein said fixation hook is coupled to said at least one conductor, such that said fixation hook comprises an electrode of said lead.

6. A lead and introducer system in accordance with claim 1, wherein said electrode assembly further comprises a steroid-silicone compound element disposed within said electrode assembly.

7. A lead and introducer system, comprising:

an elongated lead body having proximal and distal ends and having at least one electrical conductor extending between said proximal and distal ends;

a terminal assembly disposed on said proximal end of said lead body;

an electrode assembly, disposed at the distal end of said lead body, said electrode assembly including a first electrode disposed at the distal end thereof, said first electrode electrically connected to said conductor;

a curved fixation hook, disposed on said lead at a point spaced back from said first electrode said curved fixation hook extends radially outward from said lead for a first distance and then coils around at least a portion of said lead'"'"'s circumference;

a hollow introducer needle, disposed around said lead body, said needle having a longitudinal slit formed in a distal section of said needle.

8. A lead and introducer system in accordance with claim 7, wherein said introducer needle is provided with a longitudinal score to facilitate splitting apart said needle upon introduction and fixation of said lead.

9. A lead and introducer system in accordance with claim 7, wherein said curved fixation hook extends radially outward from said lead body at a first angle with respect to a longitudinal axis of said lead body, said first angle is less than ninety degrees.

10. An implantable lead and introducer system, comprising:

an elongate, flexible lead body having proximal and distal ends and having at least one electrical conductor extending between said proximal and distal ends;

an electrode assembly, disposed at the distal end of said lead body, said electrode assembly including a first electrode disposed at the distal end thereof, said first electrode electrically connected to said conductor

a fixation hook, disposed on said lead at a point spaced back from said first electrode, said fixation hook configured to curve around at least a portion of said lead'"'"'s circumference and adapted to engage said body tissue upon rotation of said lead;

an introducer cannula, slidably disposed on said lead body, said cannula having a longitudinal slit formed in a distal section thereof, said slit allowing said distal section of said needle to be slid distally beyond said fixation hook and over said electrode assembly.

11. A lead and introducer system in accordance with claim 10, wherein said cannula is provided with a means for permitting removal of said cannula from said lead without requiring said cannula to be removed over an end of said lead, to facilitate splitting apart said cannula upon introduction and fixation of said lead.

12. A lead and introducer system in accordance with claim 11, wherein said means for permitting removal comprise a longitudinal score line.

14. A medical electrical lead and introducer system comprising:

a terminal assembly;

a lead body having a conductor and insulative sleeve, the lead body further having a longitudinal axis, the conductor having a first end and a second end, the first end coupled to the terminal assembly, the insulative sleeve insulting an outer surface of the conductor between the first end and the second end;

an electrode coupled to the second end of the conductor;

a fixation hook having a first portion and a second portion, the first portion extending in a direction radial to the lead body, the first portion attached to the lead body at an angle to the longitudinal axis, the second portion attached to the first portion and curved; and

a hollow introducer sheath disposed over the lead body, electrode and fixation hook, the hollow introducer sheath having a slot at a distal end and a score line, the slot and the score line being collinear, the slot being greater in width than the first portion of the fixation hook.

13. A lead and introducer system in accordance with claim 16, wherein said curved fixation hook extends radially outward from said lead body at a first angle with respect to a longitudinal axis of said lead body, said first angle is less than ninety degrees.

15. A lead in accordance with claim 14, wherein the longitudinal slit extends proximal from the distal end of the sheath a first distance, the first portion is attached to the lead body at a second distance proximal from the electrode, the first distance being at least as great as the second distance.

16. A lead in accordance with claim 14, wherein the sheath comprises a hollow needle.

17. A medical electrical lead and introducer system comprising:

a terminal assembly;

a lead body having a conductor and insulative sleeve, the lead body further having a longitudinal axis, the conductor having a first end and a second end, the first end coupled to the terminal assembly, the insulative sleeve insulting an outer surface of the conductor between the first end and the second end;

an electrode coupled to the second end of the conductor;

a curved fixation hook attached to the lead body at a first angle to the longitudinal axis; and

a hollow introducer sheath disposed over the lead body, electrode and fixation hook, the hollow introducer sheath having a slot at a distal end and a score line, the slot and the score line being collinear, the slot being greater in width than the width of the fixation hook.

18. A lead in accordance with claim 17, wherein the sheath comprises a hollow needle.