EMF Health-effects Research

Microwave catheter ablation of the atrioventricular junction in closed-chest dogs

Lin JC, Hariman RJ, Wang YJ, Wang YG

Medical & Biological Engineering & Computing. 34(4):295-298, 1996

Previous studies have shown the feasibility of ablating the atrioventricular junction with microwave catheter antennas. However, precise placement of the catheter antenna's tip relative to the bundle of His is difficult with the stiff-necked catheter antennas. We developed a new catheter antenna geometry that provides 9F, flexible, curved tip.

Microwave catheter ablation of the atrioventricular (AV) junction was tested in 10 dogs, with an average weight of 28 kg, to evaluate the performance of the new design.

Under fluoroscopic guidance, the tip of the catheter antenna was advanced to the heart via either right femoral vein or right common carotid artery or both. The same catheter antenna was used to localize the His bundle by recording the His potential bipolarly. Then a burst of 2.45 GHz microwave energy was delivered to the AV junction. Complete AV block was induced in 6 dogs using the femoral approach and in 4 more dogs using the carotid approach.

The treatment consisted of 1 - 5 applications of 30 watts of microwave energy in 7 - 11 s (210 - 330 J per application). The new design of the microwave catheter antenna allows easier maneuver of the catheter for localization and ablation of the AV junction. Microwave ablation of the AV junction can be achieved successfully with the new design catheter antennas.

Additional Web Notes

Note: The bundle of His, called also atrioventricular bundle, is a small band of specialized muscle fibers inside the heart, and it is located at the base of the right atrium near the wall between the ventricles. It passes through the atrioventricular junction and divides into two branches. It constitutes the only myocardial conduction link of electrical impulse between the atria and ventricles.

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