Subxyphoid epicardial ablation

1. A method of creating a lesion on a surface of a heart in a body of a patient, the method comprising:

creating an incision to access a chest cavity of the patient;

creating an opening in a pericardium of the patient;

advancing a guidewire into a pericardial space;

advancing a dilation device over the guidewire and into the pericardial space;

creating a path within the pericardial space by repeatedly expanding and collapsing the dilation device within the pericardial space to dilate the pericardium; and

forming a lesion on the surface of the heart.

2. The method of claim 1 , further comprising advancing a treatment device through the path to position the treatment device against the surface of the heart to create the lesion.

3. The method of claim 2 , further comprising withdrawing the dilation device from the guidewire, and where advancing the treatment device comprises advancing the treatment device over the guidewire.

4. The method of claim 1 , where the guidewire comprises a steerable guidewire, the method further comprising steering the guidewire to advance the guidewire.

5. The method of claim 1 , further comprising expanding the dilating device during creating of the lesion to separate an anatomical structure from the heart surface.

6. The method of claim 5 , where the anatomical structure comprises a structure selected from a phrenic nerve or an esophagus.

7. The method of claim 1 , further comprising cooling tissue using the dilation device before, during or after creating of the lesion.

8. The method of claim 1 , where the dilation device comprises a fluid expandable balloon.

9. The method of claim 1 , where the dilation device comprises a mechanically expandable structure.

10. The method of claim 1 , further comprising delivering a fluid to the pericardial space.

11. The method of claim 10 , where delivering the fluid to the pericardial space comprises maintaining a fluid layer between the heart surface and the pericardium.

12. The method of claim 11 , where maintaining the fluid layer between the heart surface and the pericardium comprises cooling the surface of the heart.

13. The method of claim 11 , further comprising advancing a visualization device into the fluid layer to maintain visualization of the surface of the heart during creating the lesion.

14. The method of claim 11 , further comprising delivering a contrast agent to the pericardial space.

15. The method of claim 11 , further comprising delivering a medicament substance to assist in healing of heart tissue.

16. The method of claim 1 , further comprising remotely tracking the dilation device to localize a position of the dilation device from outside the body of the patient.

17. The method of claim 2 , where the treatment device comprises a steering mechanism and where advancing the treatment device comprises steering the treatment device.

18. The method of claim 2 , further where the dilation device is coupled to the treatment device.

19. The method of claim 1 , further where the dilation device is coupled to a guidewire.

20. The method of claim 2 , where the treatment device comprises an opening exposing an electrode, the treatment device also comprising a vacuum lumen in fluid communication with a vacuum source and a fluid perfusion lumen fluid communication with a fluid source, where both the vacuum lumen and fluid perfusion lumen are fluidly coupled to the opening.

21. The method of claim 20 , further comprising drawing a vacuum in the vacuum source to cause a drop in pressure in both the vacuum lumen and the opening, whereupon placing the opening against a soft tissue of the surface of the heart creates a seal against the soft tissue to cause the fluid perfusion lumen to drop in pressure resulting in fluid flow from the fluid source through the fluid perfusion lumen across the opening and through the vacuum lumen, where when uncovered the opening prevents the perfusion lumen from reducing in pressure and preventing fluid flow.

22. The method of claim 20 , where forming the lesion on the surface of the heart comprises applying RF energy to using the electrode to create a contiguous transmural lesion in atrial tissue of the heart.

23. The method of claim 22 , where creating the contiguous transmural lesion comprises creating a series of contiguous transmural lesions.

24. The method of claim 22 , where advancing the treatment device comprises advancing the treatment device to a plurality of regions to create a pattern of lesions on the surface of the heart.

25. The method of claim 20 , where advancing the treatment device to an irregular surface of a soft tissue comprises advancing the treatment device during a procedure selected from the group consisting of an arthroscopic, laparoscopic, and other minimally invasive procedure.

26. The method of claim 20 , where forming the lesion on the surface of the heart comprises applying vibrational energy to the electrode to create a contiguous transmural lesion in atrial tissue.

27. The method of claim 20 , where the electrode has a length and conforms to the surface of the heart to create a curvilinear lesion.

28. The method of claim 20 , where a portion of the treatment device housing the electrode is pre-shapeable to assume a shape and where the lesion forms in the shape.

29. The method of claim 20 , further comprising advancing a track adjacent to an irregular surface and where advancing the treatment device to the irregular surface comprises advancing the treatment device over the track.

30. The method of claim 29 , where the track comprises a device selected from the group consisting of a wire, a steerable catheter, a steerable guide-wire, a shaped tube, and a shaped mandrel.

31. The method of claim 1 , further comprising positioning the dilation device within a desired location in the pericardial space prior to dilating the pericardium.