Thoracoscopic epicardial radiofrequency ablation for vagal atrial fibrillation in dogs

Epicardial radiofrequency catheter ablation of the atria in the open-chest dog has been shown to reduce inducibility of atrial fibrillation. Video-ass isted endoscopic techniques decrease the operative trauma in adult thoracic surgery. We report our results of video-assisted thoracoscopic radiofreque ncy catheter ablation of the atria for the prevention of atrial fibrillatio n induction in canines. In 12 consecutive anesthetized dogs, induction of s ustained atrial fibrillation was reproducibly obtained by burst pacing and cervical vagal stimulation. In six dogs, biatrial ablation Il as performed through right and left minithoracotomies and guided by video-assisted endos copic techniques. The remaining six dogs underwent a video-guided left atri al procedure. Long continuous and transmural lesions were produced using ep icardial temperature controlled radiofrequency energy delivered according t o a simplified maze approach. Transmural lesions were demonstrated at the e nd of the study by examination of the heart. Sustained atrial fibrillation was still inducible after the right atrial ablation but sustained atrial fi brillation could not be induced following left atrial ablation. In acute ca nine studies: (1) epicardial radiofrequency catheter ablation of the atria is feasible using video-assisted endoscopic techniques; (2) ablation extend ed or confined to the left atrium appears to be effective in preventing the inducibility of sustained vagal atrial fibrillation; and (3) ablation of t he right atrium alone had no antiarrhythmic effect.