Role of Arrhythmogenic Superior Vena Cava on Atrial Fibrillation

Arrhythmogenic SVC and AF Background It is well known that superior vena cava (SVC) is one of the important non-pulmonary vein (PV) foci of atrial fibrillation (AF). However, little is known regarding the role of arrhythmogenic SVC in AF. Methods and Results Among 1,425 patients who underwent AF ablation in 2 centers, PV antrum isolation was performed in all and SVC isolation was added in 74 (5.2%) patients with arrhythmogenic SVC (58 +/- 10 years; 54 males) when the latter was identified as an AF source. The arrhythmogenicity was identified at the 1st, 2nd, and 3rd procedures in 62 (83.8%), 7 (9.5%), and 5 (6.7%) patients, respectively. In 7 (9.5%), 26 (35.1%), and 14 (18.9%) patients, it was identified following adenosine injection, isoproterenol infusion, and electrical cardioversion, respectively. SVC triggering AF was identified in 58 out of 74 (78.4%) patients. In this subset, AF initiated from SVC; however, AF cycle length was longer in SVC than in the right atrium once AF persisted, which suggested its role as an initiator. In 24 (32.4%) patients following the isolation of SVC, AF terminated or converted to atrial flutter and/or confined SVC tachycardia/fibrillation was observed, which suggested its role as a perpetuator. Sixty-four (86.5%) of 74 patients were free from any atrial tachyarrhythmias without antiarrhythmic drugs mean 12.1 +/- 9.4 months after the last ablation procedure (mean 1.38 procedures/patient). Conclusions In a subset of patients, SVC plays a role in AF not only as an initiator/trigger but also as a driver/perpetuator.