Ultrasound pulmonary vein isolation

• US 20040102769A1
• Filed: 11/26/2002
• Published: 05/27/2004
• Est. Priority Date: 11/26/2002
• Status: Active Grant

• Current Assignee: Biosense, Inc. (Cardinal Health, Inc.)
• Original Assignee: Biosense, Inc. (Cardinal Health, Inc.)
• Inventors: Govari, Assaf, Schwartz, Yitzhack
• Granted Patent: US 7,156,816 B2
• Time in Patent Office: Days
• US Class Current: 606/27
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61N 7/022 intracavitary

Abstract

A catheter introduction apparatus provides an ultrasound assembly for emission of ultrasound energy. In one application the catheter and the ultrasound assembly are introduced percutaneously, and transseptally advanced to the ostium of a pulmonary vein. An anchoring balloon is expanded to center an acoustic lens in the lumen of the pulmonary vein, such that energy is converged circumferentially onto the wall of the pulmonary vein when a transducer is energized. A circumferential ablation lesion is produced in the myocardial sleeve of the pulmonary vein, which effectively blocks electrical propagation between the pulmonary vein and the left atrium.

Claims

1. A method for electrically isolating a left atrium of a heart from a pulmonary vein, comprising the steps of:

introducing an ultrasound assembly into said heart proximate an ostium of said pulmonary vein;

anchoring said ultrasound assembly to said pulmonary vein using an anchor; and

thereafter conducting ultrasound energy in a path extending from said ultrasound assembly to a circumferential ablation region of said pulmonary vein, said path substantially avoiding said anchor.

2. The method according to claim 1, wherein said step of conducting said ultrasound energy is performed by converging said ultrasound energy into a circumferential line of focus that intersects said ablation region.

3. The method according to claim 1, wherein said anchor comprises a balloon, and said step of aligning is performed by expanding said balloon to engage said pulmonary vein.

4. The method according to claim 1, wherein said step of conducting said ultrasound energy is performed in exactly one application.

5. The method according to claim 4, wherein a duration of said one application is less than 300 seconds.

6. The method according to claim 1, wherein said step of introducing is performed by:

disposing said ultrasound assembly on an intravascular catheter; and

passing a distal portion of said intravascular catheter through a blood vessel into said heart, wherein said ultrasound assembly is spaced apart from said ablation region, wherein said path has a generally forward direction from said ultrasound assembly toward said ablation region.

7. The method according to claim 6, wherein said step of passing said distal portion of said intravascular catheter comprises activating said ultrasound assembly to apply ultrasound energy to a fossa ovalis of said heart.

8. The method according to claim 1, further comprising the step of adjusting a beam of said ultrasound energy to conform to an anatomy of said ablation region.

9. The method according to claim 1, further comprising the step of conducting an effective amount of energy from said ultrasound assembly to ablate a portion of a fossa ovalis of said heart while performing said step of introducing said ultrasound assembly.

10. An apparatus for electrically isolating a cardiac chamber, comprising:

an intravascular catheter having a distal end;

an anchor proximate said distal end; and

an ultrasound transducer assembly disposed external to said anchor for emitting ultrasound energy that is directed to a circumferential ablation region, a path of said ultrasound energy substantially avoiding said anchor.

11. The apparatus according to claim 10, further comprising a sensor disposed in said catheter for detecting cardiac electrical activity.

12. The apparatus according to claim 11, further comprising a transmitting antenna disposed in said catheter for transmitting signals from said sensor.

13. The apparatus according to claim 10, wherein said anchor comprises a balloon.

14. The apparatus according to claim 10, wherein a body section of said ultrasound transducer assembly has a proximal cross section and a distal cross section, said proximal cross section being larger than said distal cross section.

15. The apparatus according to claim 14, wherein said body section is a truncated cone.

16. The apparatus according to claim 15, wherein an inclination angle of said truncated cone is about 20 degrees.

17. The apparatus according to claim 10, wherein said ultrasound transducer assembly comprises an omnidirectional lens that focuses a beam of said ultrasound energy circumferentially on said ablation region.

18. The apparatus according to claim 17, wherein said ultrasound transducer assembly comprises an array of transducer elements, and a control unit for controlling individual ones of said transducer elements to shape said beam.

19. The apparatus according to claim 10, wherein in an operational position said ultrasound transducer assembly is spaced apart from said ablation region.

20. The apparatus according to claim 10, wherein said ultrasound transducer assembly operates at a frequency of between about 3 and 4 MHz.

21. The apparatus according to claim 10, wherein said ultrasound transducer assembly comprises:

a diffraction grating for directing said ultrasound energy that is output from said ultrasound transducer assembly in a desired direction; and

a transducer layer capable of transducing energy delivered thereto at different frequencies, said transducer layer being disposed within said catheter proximate said diffraction grating.

22. The apparatus according to claim 21, wherein said diffraction grating is a thin-film disposed on an external surface of said catheter.

23. The apparatus according to claim 10, wherein said ultrasound transducer assembly has a bandwidth that is between about 50% and about 80% of a primary operating frequency thereof.

35. The apparatus according to claim 10, wherein said ultrasound transducer assembly has a bandwidth that is between about 50% and about 80% of a primary operating frequency thereof.

24. An apparatus for electrically isolating a cardiac chamber, comprising:

an intravascular catheter;

an anchor disposed proximate a distal end of said catheter; and

an ultrasound transducer assembly disposed proximal to said anchor for emitting ultrasound energy, a path of said ultrasound energy substantially avoiding said anchor, wherein a body section of said ultrasound transducer assembly has a proximal cross sectional area and a distal cross sectional area, said proximal cross sectional area being larger than said distal cross sectional area, and wherein said ultrasound transducer assembly emits said ultrasound energy as a beam that is focused on an ablation region that substantially surrounds said ultrasound transducer assembly.

25. The apparatus according to claim 24, further comprising a sensor disposed in said catheter for detecting cardiac electrical activity.

26. The apparatus according to claim 25, further comprising a transmitting antenna disposed in said catheter for transmitting signals from said sensor.

27. The apparatus according to claim 24, wherein said anchor comprises a balloon.

28. The apparatus according to claim 24, wherein said body section is a truncated cone.

29. The apparatus according to claim 28, wherein an inclination angle of said truncated cone is about 20 degrees.

30. The apparatus according to claim 24, wherein said ultrasound transducer assembly comprises an array of transducer elements, and a control unit for controlling individual ones of said transducer elements to shape said beam.

31. The apparatus according to claim 24, wherein in an operational position said ultrasound transducer assembly is spaced apart from said ablation region.

32. The apparatus according to claim 24, wherein said ultrasound transducer assembly operates at a frequency of between about 3 and 4 MHz.

33. The apparatus according to claim 24, wherein said ultrasound transducer assembly comprises:

a diffraction grating for directing said ultrasound energy that is output from said ultrasound transducer assembly in a desired direction; and

a transducer layer capable of transducing energy delivered thereto at different frequencies, said transducer layer being disposed within said catheter proximate said diffraction grating.

34. The apparatus according to claim 33, wherein said diffraction grating is a thin-film disposed on an external surface of said catheter.