Electrode Spacing in a Subcutaneous Implantable Cardiac Stimulus Device

• US 20100152798A1
• Filed: 12/11/2009
• Published: 06/17/2010
• Est. Priority Date: 12/12/2008
• Status: Active Grant

• Current Assignee: Cameron Incorporated (Schlumberger NV)
• Original Assignee: Cameron Incorporated (Schlumberger NV)
• Inventors: Scheck, Don E., Sudam, Abdulkader O., King, Eric F., Warren, Jay A., Sanghera, Rick
• Granted Patent: US 8,483,841 B2
• Time in Patent Office: Days
• US Class Current: 607/5
• CPC Class Codes: A61N 1/048 Electrodes characterised by a specific connection between lead and electrode
• CPC Class Codes: A61N 1/0504 Subcutaneous electrodes
• CPC Class Codes: A61N 1/0563 specially adapted for defibrillation or cardioversion
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: A61N 1/3968 Constructional arrangements, e.g. casings A61N1/375 takes precedence
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock

Abstract

Methods and implantable cardiac stimulus devices that include leads designed to avoid post-shock afterpotentials. Some examples are directed toward lead-electrode designs that reduce the impact of an applied stimulus on sensing attributes. These examples may find particular use in systems that provide both sensing and therapy delivery from subcutaneous location

Claims

1. A method of treating a patient comprising:

implanting a cardiac stimulus system into a patient, the cardiac stimulus system including a canister having an electrode and a defibrillation lead having proximal and distal ends, the proximal end being connected to the canister, the defibrillation lead including a distal portion having a defibrillation coil and a distal sensing electrode disposed distal of the defibrillation coil, such that each of the canister and the defibrillation lead are implanted subcutaneously over the ribs of the patient;

delivering stimulus to the patient using the defibrillation coil and the canister electrode; and

sensing cardiac activity of the patient following delivery of the stimulus using the distal sensing electrode;

wherein the defibrillation lead is constructed such that a gap is defined between a proximal side of the distal sense electrode and a distal end of the defibrillation coil, and the gap is at least nineteen (19) millimeters, with no other electrode therebetween.

2. The method of claim 1 wherein the distance between the coil electrode and the distal electrode limits post-therapy perturbations from creating sensing artifacts if subjected to transcutaneous manipulation.

3. The method of claim 1 wherein the step of implanting a cardiac stimulus system includes placing the canister at approximately the left axilla of the patient with the defibrillation lead extending from the canister to the sternum of the patient and then along the sternum, such that the defibrillation coil is disposed parallel to the sternum, and the step of implanting further includes securing the defibrillation lead to the subcutaneous tissue of the patient.

4. The method of claim 3 wherein the step of implanting further includes securing the defibrillation lead to the subcutaneous tissue of the patient approximately at the xiphoid of the patient using a suture sleeve.

5. The method of claim 1 wherein the gap is at least twenty-four (24) millimeters.

6. The method of claim 1 wherein the step of implanting a cardiac stimulus system includes placing the canister approximately anterior of the left axilla of the patient with the defibrillation lead extending posteriorly from the canister to a location on the back of the patient such that a defibrillation vector between the coil and the canister is generally anterior-posterior in direction.

7. The method of claim 1 wherein:

the distal portion of the defibrillation lead further includes a proximal sensing electrode having proximal and distal sides; and

a gap between the proximal end of the defibrillation coil and the distal side of the proximal sensing electrode is at least nineteen (19) mm.

8. The method of claim 7 wherein the step of sensing cardiac activity of the patient following delivery of the stimulus further uses the proximal sensing electrode in conjunction with the distal sensing electrode.

9. The method of claim 7 wherein the distances between the coil electrode and the proximal and distal sensing electrodes prevents the creation of sensing artifacts in response to transcutaneous manipulation.

10. The method of claim 1 further comprising implanting a transvenous lead in addition to the defibrillation lead, wherein the transvenous lead is implanted such that it enters the venous system of the patient.

11. A method of treating a patient comprising:

implanting a cardiac stimulus system into a patient'"'"'s including implanting a canister having an electrode and a defibrillation lead having proximal and distal ends, the proximal end being connected to the canister, the defibrillation lead including a distal portion having a defibrillation coil and a proximal sensing electrode disposed proximal of the defibrillation coil, such that each of the canister and the defibrillation lead are implanted subcutaneously over the ribs of the patient;

delivering stimulus to the patient using the defibrillation coil and the canister electrode; and

sensing cardiac activity of the patient following delivery of the stimulus using at least the proximal sensing electrode;

wherein the defibrillation lead is constructed as follows;

the distance from the proximal end of the defibrillation coil to a distal side of the proximal sense electrode is approximately nineteen (19) millimeters or greater, with no other electrode therebetween.

12. The method of claim 11 wherein the distance between the coil electrode and the proximal sense electrode is chosen to limit post-therapy perturbations from creating sensing artifacts if subjected to transcutaneous manipulation.

13. The method of claim 11 wherein the step of implanting a cardiac stimulus system includes placing the canister at approximately the left axilla of the patient with the defibrillation lead extending from the canister to the sternum of the patient and then along the sternum, such that the proximal sensing electrode is disposed at approximately the patient'"'"'s xiphoid and the defibrillation coil is disposed parallel to the sternum, and the step of implanting further includes securing the distal end of the defibrillation lead to the subcutaneous tissue of the patient.

14. The method of claim 11 wherein the distance from a distal side of the proximal sense electrode to the proximal end of the defibrillation coil is approximately twenty-four (24) millimeters or greater.

15. The method of claim 11 wherein the step of implanting a cardiac stimulus system includes placing the canister approximately anterior of the left axilla of the patient with the defibrillation lead extending posteriorly from the canister to a location to the left of the spine of the patient such that a defibrillation vector between the coil and the canister is generally anterior-posterior in direction.

16. A method of treating a patient comprising:

implanting a cardiac stimulus system comprising a canister attached to first and second leads into the patient such that the first and second leads generally parallel one another over the ribcage of the patient, wherein one of the first and second leads comprises a defibrillation electrode and the other comprises a sensing electrode such that, when implantation is complete, the defibrillation electrode and sensing electrode are spaced apart from one another by a distance sufficient to prevent oversensing during transcutaneous manipulation following stimulus;

delivering therapy to the patient;

sensing cardiac activity of the patient following therapy delivery using at least the sensing electrode.

17. The method of claim 16 wherein the implanting step is performed such that the first lead is disposed to the left of the center of the patient'"'"'s sternum and the second lead is disposed to the right of the center of the patient'"'"'s sternum, and the distance between the sensing electrode and the defibrillation electrode is at least nineteen (19) millimeters.

18. A subcutaneous defibrillation lead comprising:

a proximal connector end for coupling to an implantable cardioverter-defibrillator canister;

a distal end;

an elongated body extending between the proximal connector end and the distal end;

a defibrillation electrode; and

a sensing electrode;

wherein the sensing electrode is spaced from the defibrillation electrode by a portion of the elongated body having a length of at least nineteen (19) millimeters, with no other electrode therebetween.

19. The subcutaneous defibrillation lead of claim 18 wherein the sensing electrode is a proximal sensing electrode and the subcutaneous defibrillation lead further comprises a tip sensing electrode, wherein:

the tip sensing electrode is disposed at the distal end of the subcutaneous defibrillation lead, with the defibrillation electrode disposed proximal of the tip sensing electrode and spaced therefrom by a portion of the elongated body having a length of at least nineteen (19) millimeters with no other electrode therebetween; and

the proximal sensing electrode is disposed proximal of the defibrillation electrode.

20. The subcutaneous defibrillation lead of claim 19 wherein the spacing between the defibrillation electrode and the tip and proximal sensing electrodes is sized such that, following delivery of a defibrillation therapy to a patient, afterpotential is minimized.