Systems and methods for tissue mapping and ablation

• US 5,916,213 A
• Filed: 02/04/1997
• Issued: 06/29/1999
• Est. Priority Date: 02/04/1997
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Bruszewski, Walter, Gaiser, John, Nguyen, Huu, Maguire, Mark, Le, Le, Haissaguerre, Michel
• Primary Examiner(s): Lavinder, Jack W.
• Assistant Examiner(s): RUDDY, DAVID M
• Application Number:
  US08/794,804
• Time in Patent Office: 875 Days
• Field of Search: 128/898, 600/373, 600/374, 600/375, 600/377, 600/381, 607/122, 607/119, 606/32, 606/41, 606/46, 606/47
• US Class Current: 606/41
• CPC Class Codes: A61B 18/08 by means of electrically-heated probes
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2017/2945 Curved jaws
• CPC Class Codes: A61B 2018/00011 with fluids
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00839 Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 2018/00898 Alarms or notifications created in response to an abnormal condition
• CPC Class Codes: A61B 2018/0091 Handpieces of the surgical instrument or device
• CPC Class Codes: A61B 2018/1432 curved
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2218/002 Irrigation

Abstract

A steerable electrophysiology catheter includes a shaft having a distal ablation segment with one or more electrodes coupled to a source of electrical energy by a connector extending through the shaft. The distal ablation segment of the shaft is movable between a collapsed configuration sized for percutaneous introduction into the patient and/or endoluminal delivery to the target site and an expanded configuration, in which the distal ablation segment forms a substantially continuous surface transverse to the shaft axis for engaging the heart tissue and creating a linear lesion thereon. The catheter includes one or more force element(s) positioned to apply an axial force between the distal and proximal ends of the ablation segment. The force element(s) provide a sufficiently uniform force against the distal ablation segment to establish continuous contact pressure between the electrodes and the patient'"'"'s heart tissue. This contact pressure allows the surgeon to engage the entire length of the distal ablation segment against the heart tissue to provide a relatively long linear lesion on this tissue.

Claims

1. An apparatus for recording electrical signals and/or for applying energy to a target site within a patient comprising:

a shaft having distal and proximal end portions and a longitudinal axis therebetween;

an ablation segment comprising first and second arms pivotally mounted to the distal end portion of the shaft by a hinge for movement between generally parallel and spaced-apart positions, the arms each having a distal end spaced-apart from the hinge, each arm having a plurality of ablation electrodes;

a connector extending through the shaft for electrically coupling the electrodes to a source of electrical energy; and

a force element coupled to the shaft and disposed to apply an axially directed force to the arms between the distal ends of the arms.

2. The apparatus of claim 1 wherein the source of electrical energy is a Radiofrequency generator.

3. The apparatus of claim 1 wherein the ablation segment is sized for delivery through a percutaneous penetration in the patient when the arms are in the generally parallel position, the ablation segment forming a substantially continuous surface transverse to the longitudinal axis of the shaft for contacting tissue at the target site when the arms are in the spaced-apart position.

4. The apparatus of claim 3 wherein the force element is disposed to apply an axial force at a central portion of the continuous surface formed by the ablation segment.

5. The apparatus of claim 3 wherein the substantially continuous surface formed by the ablation segment is linear.

6. The apparatus of claim 5 wherein the continuous surface is substantially perpendicular to the shaft axis.

7. The apparatus of claim 1 wherein the force element comprises an actuator at the proximal end of the shaft, and one or more manipulator elements extending through the shaft from the actuator to the first and second arms.

8. The apparatus of claim 7 wherein the manipulator elements are pulled proximally to close the arms.

9. The apparatus of claim 7 wherein the manipulator elements are pushed distally to close the arms.

10. The apparatus of claim 7 wherein the manipulator elements are coupled to the hinge assembly for pivoting the arms about the hinge, and for applying an axial force to the arms in the spaced-apart position to maintain contact pressure between the arms and the patient'"'"'s tissue.

11. The apparatus of claim 1 wherein the distal end portion of the shaft has a curvature, the apparatus further comprising an actuator coupled to the proximal end of the shaft for adjusting said curvature.

12. The apparatus of claim 1 further comprising an actuator coupled to the proximal end of the shaft for rotating the ablation segment about the shaft axis.

13. The apparatus of claim 1 wherein the first and second arms each define a planar contact surface opposite the shaft in the spaced-apart position for contacting tissue, the electrodes being coupled to the contact surface.

14. The apparatus of claim 1 further comprising flexible printed circuits coupling the electrodes to the connector.

15. The apparatus of claim 1 wherein the shaft comprises an inner lumen and the ablation segment comprises one or more holes fluidly coupled to the inner lumen for directing fluid through the ablation segment to exchange heat with the electrodes.

16. The apparatus of claim 15 wherein the holes are sized and configured to direct the fluid onto the tissue at the target site to bathe the tissue interface.

17. The apparatus of claim 15 wherein the electrodes are recessed into the arms, the holes extending through the electrodes to direct the fluid between the electrodes and the tissue to create a fluid interface therebetween.

18. The apparatus of claim 17 wherein the fluid is an ionic medium which conducts RF energy.

19. The apparatus of claim 1 wherein the electrodes are raised above a surface of each of the arms to improve contact with tissue.

20. The apparatus of claim 1 wherein the electrodes are divided into multiple segments to improve the flexibility of the electrodes along the arms.

21. The apparatus of claim 1 further comprising one or more temperature sensors coupled to the electrodes on the ablation segment.

22. The apparatus of claim 21 further comprising one or more flexible printed circuits coupling the electrodes with the connector, and one or more thermocouples integral with the flexible printed circuits.

23. The apparatus of claim 22 wherein the thermocouples are positioned near the electrodes, but not in direct thermal contact with the electrodes, the thermocouples being positioned at or near the tissue interface.

24. The apparatus of claim 1 wherein the ablation segment has an overall ablation length of about 2-6 cm.

25. The apparatus of claim 1 wherein the ablation segment has a ratio of width to length of one to at least about fourteen.

26. A method for applying energy to a target site in a patient'"'"'s body comprising:

selecting an electrode catheter having a distal ablation segment, the distal ablation segment comprising first and second arms pivotally mounted to a distal end portion of a shaft of the catheter by a hinge, the arms each having a plurality of ablation electrodes and a distal end spaced-apart from the hinge;

pivoting the arms from a first, generally parallel position to a second, expanded position at which the distal ends are spaced-apart from one another;

contacting tissue at a target site with said plurality of electrodes on each of the spaced-apart arms, said catheter defining a catheter axis;

applying an axial force to the ablation segment between the distal ends of the arms to maintain contact pressure between the electrodes and the tissue; and

applying energy to the electrodes and to the tissue at the target site.

27. The method of claim 26 further comprising:

delivering the ablation segment and the distal end of the catheter shaft through a percutaneous penetration in the patient; and

endoluminally advancing the ablation segment to the target site.

28. The method of claim 26 further comprising:

delivering the ablation segment and the distal end of the catheter shaft through an intercostal penetration in the patient into the thoracic cavity; and

positioning the ablation segment adjacent the target site on the epicardium.

29. The method of claim 26 wherein the arms are substantially transverse to the shaft axis when in the second, expanded position.

30. The method of claim 29 further comprising applying an axial force near a center portion of the ablation segment to create sufficient contact pressure along substantially the entire length of the ablation segment and the patient'"'"'s tissue.

31. The method of claim 26 further comprising closing the first and second arms into an acute angle relative to each other so as to grasp a cardiac structure.

32. The method of claim 26 further comprising applying force to the hinge in the expanded position to maintain continuous contact pressure between the arms and the tissue.

33. The method of claim 26 further comprising rotating the ablation segment about the shaft axis.

34. The method of claim 26 further comprising delivering coolant fluid through an inner lumen in the shaft into the ablation segment to exchange heat with the electrodes.

35. The method of claim 26 further comprising delivering a conductive fluid between the tissue at the target site and the electrodes to create a fluid interface that conducts RF energy from the electrodes to the tissue.

36. The method of claim 26 further comprising measuring a temperature of the tissue at the target site with temperature sensors coupled to the electrodes.

37. The method of claim 26 wherein the ablation segment is pressed against heart tissue at the target site, and a distally directed force is applied to the ablation segment.

38. The method of claim 26 further comprising:

delivering the ablation segment through an opening in a body vessel;

moving the arms in the expanded position to be substantially transverse to the catheter axis; and

pulling the catheter back into the opening such that the arms are pressed against the tissue surrounding the opening.

39. The method of claim 26 further comprising:

delivering the ablation segment from the right atrium through a transseptal puncture into the left atrium;

moving the arms in the expanded position to be substantially transverse to the catheter axis; and

pulling the catheter back through the transseptal puncture such that the arms are pressed against the septal tissue surrounding the opening.

40. The method of claim 26 further comprising:

delivering the ablation segment across the mitral valve into the left atrium;

moving the arms in the expanded position to be substantially transverse to the catheter axis; and

advancing the catheter back such that the arms are pressed against atrial wall spanning ostial of the pulmonary veins or atrial wall between any pulmonary vein ostium and the mitral annulus.

41. The method of claim 32 further comprising:

delivering the ablation segment through the mitral valve into the left atrium;

moving the arms in the expanded position to be substantially transverse to the catheter axis; and

pulling the catheter back through the mitral valve such that at least a portion of the arms are pressed against the mitral valve annulus.