Catheter ablation of cardiac autonomic nerves for prevention of vagal atrial fibrillation

Background-Vagal stimulation shortens the atrial effective refractory perio d (AERP) and maintains atrial fibrillation (AF). This study investigated wh ether the parasympathetic pathways that innervate the atria can be identifi ed and ablated by use of transvenous catheter stimulation and radiofrequenc y current catheter ablation (RFCA) techniques. Methods and Results-In 11 dogs, AERPs were determined at 7 atrial sites dur ing bilateral cervical vagal nerve stimulation (VNS) and electrical stimula tion of the third fat pad (20 Hz) in the right pulmonary artery (RPA). VNS shortened the AERP at all sites from 123+/-4 to 39+/-4 ms, P<0.001) and inc reased the covariance of AERP (COV-AERP) (from 9+/-3% to 27+/-13%, P<0.001) . RPA stimulation shortened the AERP at all sites from 123+/-4 to 66+/-13 m s (P<0.001) and increased the COV-AERP from 9+/-3% to 30+/-12% (P<0.001). I n 7 dogs, transvascular RFCA of the parasympathetic pathways along the RPA was performed, and in 3 dogs, additional RFCA of parasympathetic fibers alo ng the inferior (n=2) or superior (n=1) vena cava was performed. RFCA blunt ed the AERP shortening at all sites during VNS (114+/-4 ms after RFCA), abo lished the increase of COV-AERP during VNS (12+/-7% after RFCA), and led to an increase of the baseline AERP (123+/-4 ms before versus 127+/-3 ms afte r RFCA, P=0.002). Before RFCA, AF could be induced and maintained as long a s VNS was continued, whereas after RFCA, AF was no longer inducible during VNS. Conclusions-Transvascular atrial parasympathetic nerve system modification by RFCA abolishes vagally mediated AF. This antifibrillatory procedure may provide a foundation for investigating the usefulness of neural ablation in chronic animal models of AF and eventually in patients with AF and high va gal tone.