Cardiac ablation devices

Abstract

A cardiac ablation device treats atrial fibrillation by directing and focusing ultrasonic waves into a ring-like ablation region (A). The device desirably is steerable and can be moved between a normal disposition, in which the ablation region lies parallel to the wall of the heart for ablating a loop-like lesion, and a canted disposition, in which the ring-like focal region is tilted relative to the wall of the heart, to ablate only a short, substantially linear lesion. The ablation device desirably includes a balloon reflector structure (18, 1310) and an ultrasonic emitter assembly (23, 1326), and can be steered and positioned without reference to engagement between the device and the pulmonary vein or ostium. A contrast medium (C) can be injected through the ablation device to facilitate imaging, so that the device can be positioned based on observation of the images.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application is a continuation of U.S. patent application Ser. No. 10 / 783,310, filed Feb. 20, 2004, now U.S. Pat. No. 7,837,676, which claims benefit of U.S. Provisional Patent Application Ser. No. 60 / 448,804, filed Feb. 20, 2003, the entire contents of both of which are hereby incorporated by reference herein.BACKGROUND OF THE INVENTION[0002]The present invention relates to ablation apparatus and methods and to steerable devices, including those used in cardiac ablation[0003]Contraction or “beating” of the heart is controlled by electrical impulses generated at nodes within the heart and transmitted along conductive pathways extending within the wall of the heart. Certain diseases of the heart known as cardiac arrhythmias involve abnormal generation or conduction of the electrical impulses. One such arrhythmia is atrial fibrillation or “AF.” Certain cardiac arrhythmias can be treated by deliberately damaging the tissue along a...

AI Technical Summary

Benefits of technology

Facilitates precise and efficient cardiac ablation by allowing real-time imaging confirmation of device placement, reducing tissue damage, and simplifying the procedure with a single device capable of forming both loop-like and linear lesions, while maintaining the ablation device in an expanded, operative condition for maneuverability.

Problems solved by technology

Also, two or more pulmonary veins may join one another close to a common opening or ostium or may be enlarged or shaped so that it is difficult to engage the tip in the ostium.

Moreover, even where the patient has the desired, nominal anatomy, it has been difficult to confirm proper placement of the balloon assembly.

The delicate tissues within the pulmonary vein can be damaged by forcibly engaging structures with these tissues and by moving the engaged structures while the structures are forcibly engaged with the tissues.

Such a catheter may be provided as a separate device which must be separately introduced into the heart, thus complicating and prolonging the procedure.

Although this approach theoretically simplifies the task of positioning the needed devices within the heart, in fact, it substantially complicates the construction of the device and also complicates the tasks of positioning each individual device.

Images