Multiple sources initiating atrial fibrillation from a single pulmonary vein identified by a circumferential catheter

The pulmonary veins are the predominant source of ectopic activity initiati ng AF. The reproducibility of intrapulmonary vein activation during ectopic activity and/or initiation of multiple AF episodes was examined. Eighty-ni ne pulmonary veins (PVs) among 29 patients undergoing radiofrequency ablati on of AF were studied with a 15- to 20-mm diameter circumferential PV cathe ter equipped with ten electrodes and a deflectable shaft. Local electrogram s were recorded simultaneously during sinus rhythm, ectopic activity, or AF onset, spontaneously or induced via the;catheter left in a stable position . Fifty-four arrhythmogenic veins were identified, 39 showing isolated ecto py, and 8 displayed repetitive ectopy (in salvos). The earliest site of act ivation and the sequence of infra-PV activation during isolated ectopy was identical to that observed during consecutive ectopic complexes in 77% and variable in 23% during isolated ectopy. The earliest activity was sometimes limited to a single bipole. During repetitive ectopy and AF initiation, mu ltiple sources and/or variable activation patterns were noted in 53% of ins tances, indicating the presence of multiple arrhythmogenic foci within the same PV. Simultaneous electrogram recordings with a circumferential PV cath eter identified the presence of multiple arrhythmogenic foci within a singl e PV.