Arrhythmogenic Potential of Pulmonary Venous Tissue: Triggers for Atrial Fibrillation Identified within the Remnant of a Vein

BACKGROUND: Pulmonary veins (PVs) have frequently been identified as triggers for atrial fibrillation (AF), and higher arrhythmogenic potential of superior PVs has been attributed to their larger size, which can more rigorously support abnormalities of impulse formation and/or conduction. CASE REPORT: Contrary to this belief, we report our observations in a 63-year-old patient with history of lung cancer, S/P left upper lobectomy, undergoing ablation for paroxysmal AF. Circular mapping (Lasso) and ablation (ABL; 8-mm) catheters were deployed in left atrium (LA). Intracardiac ultrasound revealed separate right superior (RS) and inferior (RI) PVs and a single left PV. Segmented LA anatomy from the CT angiogram images corroborated this, although on the latter there appeared to be a "stump" at superior aspect of the left PV. This stump likely was the remnant of the left superior (LS) PV. Thus, the patent left vein was likely the dilated left inferior (LI) PV. With the Lasso and ABL deployed at the LIPV ostium and LSPV remnant, respectively, AF was reproducibly seen to initiate with earliest activity in the latter. Single radio-frequency ablation (RFA) lesion within the LSPV remnant abolished AF triggers. Additional RFA was done to isolate LI, RS, and RI PVs. Over a follow-up period of 24 months, this patient has remained free from AF off any drugs. CONCLUSIONS: Our observations suggest that even very proximal remnants of PVs can serve as triggers for AF. Recognition of this phenomenon was facilitated by the use of advanced imaging technique and the deployment of multiple catheters.