Coronary sinus lead for pacing the left atrium

1. A pacing lead for implantation in a coronary sinus having an opening and a wall defining an interior and presenting a diameter dimension, the pacing lead comprising:

an elongated lead body defining an elongated longitudinal axis; and

a preformed resilient fixation element extending from a distal end of the lead body and defining a loop structure laterally adjacent the lead body, wherein the loop structure terminates at a free lead tip having a lead tip axis and is configured to position the lead tip laterally adjacent to the lead body such that the lead tip axis intersects the elongated longitudinal axis of the elongated lead body wherein the lead tip points towards the elongated longitudinal axis of the elongated lead body, the pacing lead further including at least one electrode on either the lead body or the fixation element, the loop structure presenting a predetermined width dimension greater than the diameter dimension of the coronary sinus, wherein the loop structure is configured to be laterally compressed by the wall of the coronary sinus to bias the free lead tip against the wall of the coronary sinus laterally adjacent to the lead body and to bias the at least one electrode against the wall of the coronary sinus.

2. The lead of claim 1 , wherein the lead includes a pair of electrodes.

3. The lead of claim 2 , wherein the pair of electrodes are disposed on the lead body.

4. The lead of claim 1 , wherein the loop structure includes a generally arcuate proximal portion and a generally arcuate distal portion.

5. The lead of claim 4 , wherein the generally arcuate proximal portion subtends an angle of at least about 120 degrees.

6. The lead of claim 5 , wherein the generally arcuate proximal portion subtends at an angle of about 180 degrees.

7. The lead of claim 4 , wherein the generally arcuate distal portion subtends an angle of at least about 40 degrees.

8. The lead of claim 7 wherein the generally arcuate distal portion subtends an angle of about 90 degrees.

9. The lead of claim 4 , wherein the loop structure includes a generally straight portion between the generally arcuate proximal portion and the generally arcuate distal portion.

10. The lead of claim 1 , wherein the loop structure includes a generally straight proximal portion defining an angle with the pacing portion of less than 90 degrees.

11. The lead of claim 10 , wherein the loop structure includes a generally straight distal portion defining an angle with the generally straight proximal portion of between about 90 and about 150 degrees.

12. The lead of claim 11 , wherein the loop structure includes a generally straight portion between the generally straight proximal portion and the generally straight distal portion.

13. The lead of claim 1 , wherein the lead defines a central lumen.

14. The lead of claim 13 , wherein the central lumen extends through the lead body and the resilient fixation element.

15. The lead of claim 13 , wherein the lead defines an aperture extending from the central lumen to an exterior surface of the lead.

16. The lead of claim 1 , further comprising a catheter and a guidewire operably coupled to the catheter for guiding the lead towards the opening of the coronary sinus.

17. The lead of claim 16 , wherein the lead defines an aperture extending from the central lumen to an exterior surface of the lead, the guidewire extending through the central lumen and aperture of the lead.

18. The lead of claim 1 , wherein the lead comprises a lead width, the lead width being between 4 and 6 French.

19. The lead of claim 1 , wherein the predetermined width dimension is between about 10% and about 200% of the diameter dimension of the coronary sinus.

20. The lead of claim 1 , wherein the predetermined width dimension is between about 25% and about 75% of the diameter dimension of the coronary sinus.