Linear catheter ablation of the right atrium for rapid atrial pacing-induced sustained atrial fibrillation in dogs.

Catheter ablation of persistent/long-persistent atrial fibrillation (AF) has been shown to be less effective by pulmonary vein isolation (PVI) and additional left atrial (LA) complex fractionated atrial electrograms and long linear lesions are often required. Recent reports have demonstrated right atrial (RA) ablation increases the success rate of maintaining sinus rhythm in persistent/long-persistent AF. The aim of this study was to investigate whether effective RA linear lesions can terminate AF and render it noninducible in a canine model of rapid atrial pacing-induced sustained AF. Sustained AF was induced by rapid atrial pacing in 20 dogs. AF duration was 21-126 days (median, 50 days). Four RA linear lesions (superior vena cava-inferior vena cava, septal line, transverse line, and cavo-tricuspid line) were created with the use of 1 of 3 different ablation catheters (large-tip [8-mm tip], coil-tip, and cooled-tip catheters). AF was terminated with the large-tip catheter in 4/7 dogs (1 dog died of ventricular fibrillation [VF]), with the coil-tip catheter in 3/7 dogs (1 dog died of VF), and with the cooled-tip catheter in 1/6 dogs. In 6 dogs in which AF could not be terminated acutely by RA ablation, AF terminated spontaneously at 7-78 days (median, 14 days) after ablation. RA linear ablation terminated AF with limited success in our dog model of rapid atrial pacing-induced AF, but late AF termination was noted in the surviving dogs. Therefore, RA linear lesions in addition to the PVI and LA lesions may have additional effects on the catheter ablation for the persistent AF.