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Atrial ablation using an IRK-151 infrared coagulator in canine model.

BACKGROUND
A method of atrial ablation was developed with the aim of shortening the aortic cross-clamp time during MAZE surgery. The IRK-151 infrared coagulator (Infrarot-Kontaktkoagulator: MBB: Messerschmidt-Bolkow-Blohn, Germany) was employed. Our aim was to electrophysiologically confirm the efficacy of this device.


METHODS
The MAZE-III procedure was performed in four mongrel dogs. Instead of a pulmonary vein-encircling incision, IRK-151 was applied several times to create a continuously overlapping circular lesion. After aortic declamping, the potentials of both atria were recorded using 18 bipolar electrodes implanted in the atrial wall. The recording conditions were: 1) sinus rhythm, 2) overdrive pacing from outside the encircling coagulation, and 3) overdrive pacing from inside the encircling coagulation.


RESULTS
1) There was no detectable potential within the pulmonary vein-encircling coagulation. 2) There was no conduction of paced atrial potential inside the encircling coagulation. 3) Only the area within the encircling coagulation was activated by the stimulus. Other parts of the atrium showed sinus rhythm simultaneously.


CONCLUSIONS
The left atrium within the pulmonary vein-encircling coagulation was isolated electrophysiologically.