Epicardial Connections Between the Pulmonary Veins and Left Atrium: Relevance for Atrial Fibrillation Ablation

Abstract

Epicardial Connections Between PVs and the LA. Introduction: Some observations support the existence of epicardial connections (ECs) between ipsilateral pulmonary veins (vein to vein ECs [VVECs]), and we have observed venoatrial ECs inserted at distance from the pulmonary vein ostium (vein to atrium ECs [VAECs]). Our aim was to determine the prevalence of ECs and their relevance for pulmonary vein isolation.

Methods and Results: We studied 100 consecutive patients with drug-refractory atrial fibrillation who underwent ostial pulmonary vein isolation by cooled radiofrequency catheter ablation. A VVEC was identified if pulmonary vein pacing activated the ipsilateral vein before the atrium, requiring ablation of both venous ostia to isolate either pulmonary vein. A VAEC was identified if pacing produced atrial breakthrough located at distance from the venous ostium, requiring extraostial ablation to isolate the pulmonary vein. Patients with ECs (20%) were younger (P = 0.02) and had a higher prevalence of structural heart disease (P = 0.01) than patients without ECs. VVECs and VAECs were identified in 32 pulmonary veins (10%) and VAECs in 10 veins (3%). Veins with ECs had a higher rate of early recurrence of conduction following isolation (29% vs 11%; P = 0.01).

Conclusion: Twenty percent of patients with atrial fibrillation had ECs resistant to ostial ablation in one or more pulmonary veins. Isolating veins with ECs may require a different ablation approach. These connections are associated with an increased rate of early recurrence of conduction.