The goal of the proposed program is to develop a device for myocardial ablation using microwave heating. The device, consisting of a microprocessor-controlled solid-state microwave energy source at 915 MHz, can deliver localized heating of tissue to create ablation with a small transducer or antenna. The transducer, or applicator, is a novel adaptation of an antenna formed with thin, flexible coaxial cable that has a helically wound tip. This configuration would allow intraoperative ablation or catheter ablation for treatment of cardiac arrhythmias, particularly ventricular tachyarrhythmias. The unique feature of this ablation method is its ability to create large lesions with a depth of 2-3 mm. Using the catheter technique lesions of 1 cm or more in diameter can be created; for an intraoperative technique lesions of several centimeters across can be created. At present, no other technique -- DC shock, RF laser, other microwave antenna designs, or cryoablation -- generates such a broad, shallow lesion. In addition, the microwave technique of rapid, controlled and uniform tissue heating would overcome the disadvantage of long treatment time of other methods. To produce a 1 cm diameter lesion would take 10 seconds with the microwave method versus 5 minutes for cryoablation or 1 minute for laser techniques.
