Over-the-wire delivery of a substernal lead

1. A method of implanting a substernal lead within a patient, the lead having at least two electrodes and defining a major longitudinal axis, the patient having a heart, sternum, a caudal end of the sternum, a cranial end of the sternum, and an anterior mediastinum, and a pulmonary trunk, the method comprising:

advancing a tunneling tool posteriorly proximate the caudal end of the sternum toward a first location within the anterior mediastinum;

advancing the tunneling tool superiorly underneath the sternum through the anterior mediastinum from the first location to a second location cranial to the first location and anterior to the heart;

advancing a guidewire from the first location to the second location;

sliding the lead along at least a portion of the guidewire; and

implanting the lead underneath the sternum, the lead being advanced to a position:

adjacent a posterior side of the sternum,

spanning the distance between the first location and the second location when implanted, and;

at which the at least two electrodes are disposed directly on the lead and along the major longitudinal axis.

2. The method of claim 1 , further including creating an incision proximate the caudal end of the sternum through which the tunneling tool is advanced.

3. The method of claim 1 , wherein the tunneling tool is at least one of a steerable catheter and a rigid tube.

4. The method of claim 1 , further including advancing the tunneling tool subcutaneously from the left side of the patient's torso toward the caudal end of the sternum.

5. The method of claim 1 , wherein the tunneling tool includes a lumen on its exterior sized to slideably receive the guidewire, and wherein advancing the guidewire from the first location to the second location includes advancing the guidewire through the lumen on the tunneling tool.

6. The method of claim 1 , wherein the tunneling tool is at least one of a rigid tube and a catheter having a deflectable distal end, and wherein the tunneling tool defines a lumen therethrough and an opening at its distal end, and wherein advancing the guidewire from the first location to the second location includes advancing the guidewire through the lumen of the tunneling tool and out through the opening of the distal end of the tunneling tool.

7. The method of claim 6 , wherein the tunneling tool defines an expandable ring at the distal end of the lumen, and wherein advancing the guidewire from the first location to the second location includes advancing the guidewire through the expandable ring.

8. The method of claim 1 , wherein the tunneling tool includes a plurality of rings spaced a distance away from each other along the length of the exterior of the tunneling tool, and wherein advancing the guidewire from the first location to the second location includes advancing the guidewire through the plurality of rings.

9. The method of claim 1 , wherein the tunneling tool includes a sheath disposed around its exterior, and wherein the guidewire is disposed in a space between the interior of the sheath and the exterior of the tunneling tool, and wherein advancing the guidewire from the first location to the second location includes advancing the guidewire through the space between the interior of the sheath and the exterior of the tunneling tool.

10. The method of claim 1 , wherein the tunneling tool includes a sheath disposed around its exterior, and wherein the sheath includes a lumen on its exterior sized to slideably receive the guidewire, and wherein advancing the guidewire from the first location to the second location includes advancing the guidewire through the lumen on the sheath.

11. The method of claim 1 , wherein the tunneling tool defines a lumen therethrough and includes a blunt tip at its distal end, and wherein advancing the guidewire from the first location to the second location includes advancing the guidewire through the lumen of the tunneling tool and out through the tip.

12. The method of claim 1 , wherein the lead includes at least one electrode proximate a distal end of the lead and wherein sliding the lead along at least the portion of the guidewire comprises sliding the distal end of the lead along at least the portion of the guidewire to place the distal end of the lead at the second location.

13. The method of claim 1 , wherein the first location and the second location spans at least a majority of a distance between the caudal end of the sternum and the cranial end of the sternum.

14. The method of claim 1 , wherein the lead includes at least one electrode and wherein implanting the lead underneath the sternum comprises implanting the lead underneath the sternum such that the at least one electrode is located within the anterior mediastinum.

15. The method of claim 1 , wherein the second location is proximate the cranial end of the sternum.

16. A method of implanting a substernal lead within a patient, the lead having at least three electrodes and defining a major longitudinal axis, the patient having a heart, sternum, a caudal end of the sternum, a cranial end of the sternum, and an anterior mediastinum, the method comprising:

advancing a tunneling tool posteriorly proximate the caudal end of the sternum toward a first location;

advancing the tunneling tool superiorly underneath the sternum through the anterior mediastinum from the first location to a second location cranial to the first location and anterior to the heart;

advancing a guidewire from the first location to the second location;

sliding the lead along at least a portion of the guidewire; and

implanting the lead underneath the sternum, the lead having the at least three electrodes directly coupled thereon, the lead being implanted such that the at least three electrodes are located within the anterior mediastinum, the lead is adjacent a posterior surface of the sternum, and, during use, the at least three electrodes are disposed along and parallel to the major longitudinal axis.

17. The method of claim 16 , wherein the second location is proximate the cranial end of the sternum.