Transcatheter radiofrequency ablation in the canine right atrium

The feasibility of using radiofrequency energy for potential ablation of atrial tachycardia foci was assessed by performing transcatheter ablation in the right atrium in 11 closed-chest dogs. Single-pulsed radiofrequency (750 kHz) energy was delivered to the right atrium (29-254 J) between the tip electrode of a standard 6 Fr quadripolar catheter and a chest patch electrode. There were no significant arrhythmias or complications noted. Dogs were sacrificed 0-29 days after ablation to assess acute and subacute effects of this technique. Of 47 attempted ablations, 36 well-delineated coagulative lesions were identified. The lesions had a mean dimension of 5.2 +/- 0.57 mm (+/- SE) in length, 3.9 +/- 0.27 mm in width, and 2.6 +/- 0.17 mm in depth. Transmural necrosis was noted in 6 of 36 lesions (17%) without perforation. A thin layer of mural thrombus was found in 5 of 36 lesions (14%). Thus, this technique appears to be feasible and relatively safe for right atrial ablations in a short-term follow-up period. The potential application of this method to ablate right atrial tachycardia foci needs to be further investigated.