Medical electrical lead with temporarily stiff portion

• US 5,800,497 A
• Filed: 07/17/1997
• Issued: 09/01/1998
• Est. Priority Date: 07/17/1997
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Lokhoff, Nico M., Gubbels, Paul A., Bakels, Arnoldus P.
• Primary Examiner(s): Getzow, Scott M.
• Application Number:
  US08/896,096
• Time in Patent Office: 411 Days
• Field of Search: 607/119, 607/122, 607/123, 607/120, 607/121, 600/377, 600/374, 600/373
• US Class Current: 607/122
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 2001/0585 Coronary sinus electrodes

Abstract

A medical electrical lead which features a portion of the lead body which may be made temporarily stiff. The lead preferred is designed for implantation into a body and would include electrodes for both the ventricle and the atrium. The temporarily stiff portion may be located along the lead body in the area strictly within the atrium or may also include portions of the lead body implanted in the ventricle or even in the superior vena cava. The atrial portion further includes one or more electrodes. The temporarily stiff portion is formed through the use of a cavity in the lead body filled with magnet-rheologic fluid (hereinafter called "MRF"). Once the lead is implanted, a magnet may be used to communicate with the lead body and, in particular, with the MRF filled cavity. While in the magnetic field, the MRF will become solid and the lead body in such an area will become stiffer. The lead body, moreover, in this area will also be attracted to the magnet thereby causing the lead body in that portion to migrate towards the magnet. The MRF filled cavity may either be cylindrical in cross-section or have other cross-sections, such as a semi-circle. The temporarily stiff portion may be located anywhere along the lead body between the proximal and distal ends. In the preferred embodiment the temporarily stiff portion is located between approximately 0 and 20 cm from the lead distal end and is between approximately 2 cm and 20 cm in total length. In an additional embodiment the lead is disclosed for coronary sinus placement. Finally, a further embodiment is shown which features MRF for the transfer of force from a stylet to the lead.

Claims

1. A medical electrical lead comprising:

a lead body, the lead body having a first portion and a second portion, the lead body further having an insulative sheath and a conductor, the insulative sheath having a first end and a second end, the conductor positioned within the insulative sheath and extending between the first end and the second end;

means for temporarily making a first portion of the lead body more stiff by exposing the first portion to a magnetic field; and

an electrode positioned near the second end, the electrode coupled to the conductor.

2. A medical electrical lead according to claim 1 wherein the means for temporarily making a first portion of the lead body more stiff comprises a first cavity in the first portion of the lead body, the first cavity containing a first amount of MRF.

3. A medical electrical lead according to claim 2 wherein the first cavity is within the insulative sheath.

4. A medical electrical lead according to claim 2 wherein the first cavity comprises a cylindrical cavity.

5. A medical electrical lead according to claim 4 wherein the cylindrical cavity is within the insulative sheath.

6. A medical electrical lead according to claim 2 wherein the first cavity is located approximately 8 cm from the distal tip.

7. A medical electrical lead according to claim 2 wherein the first cavity is approximately 8 cm long.

8. A medical electrical lead comprising:

a lead body, the lead body having a first portion and a second portion, the lead body further having an insulative sheath and a conductor, the insulative sheath having a first end and a second end, the conductor positioned within the insulative sheath and extending between the first end and the second end;

a stylet positioned extending from a first end of the lead body into an interior portion of the lead body

means for temporarily permitting the longitudinal transfer of force between the stylet and the lead body by exposing the lead body to a magnetic field.

9. A medical electrical lead according to claim 8 wherein the lead body has at least a first cavity in the first portion, the first cavity containing a first amount of MRF.

10. A medical electrical lead comprising:

a lead body, the lead body having a first portion and a second portion, the lead body further having an insulative sheath and a conductor, the insulative sheath having a first end and a second end, the conductor positioned within the insulative sheath and extending between the first end and the second end;

means for temporarily making the first portion of the lead body more stiff by exposing the first portion to a first magnetic field;

means for temporarily making the second portion of the lead body more stiff by exposing the second portion to a second magnetic field; and

an electrode positioned near the second end, the electrode coupled to the conductor.

11. A medical electrical lead according to claim 10 wherein the means for temporarily making a first portion of the lead body more stiff comprises a first cavity in the first portion of the lead body, the first cavity containing a first amount of MRF.

12. A medical electrical lead according to claim 10 wherein the means for temporarily making a second portion of the lead body more stiff comprises a second cavity in the second portion of the lead body, the second cavity containing a first amount of MRF.

13. A medical electrical lead according to claim 12 wherein the first cavity is within the insulative sheath.

14. A medical electrical lead according to claim 12 wherein the first cavity comprises a cylindrical cavity.

15. A medical electrical lead according to claim 14 wherein the cylindrical cavity is within the insulative sheath.

16. A medical electrical lead according to claim 12 wherein the first cavity is located approximately 8 cm from the distal tip.

17. A medical electrical lead according to claim 12 wherein the first cavity is approximately 8 cm long.