ATP revealed extra pulmonary vein source of atrial fibrillation after circumferential pulmonary vein isolation.

Noninducibility of atrial fibrillation (AF) by additional electrograms-guided ablation may benefit the clinical outcome. This report illustrates the effect of adenosine triphosphate (ATP) injection on AF inducibility after pulmonary vein (PV) isolation. AF was triggered twice by ATP without PV reconnection. Meanwhile, complex fractionated atrial electrograms (CFAEs) were observed, and ablation targets on these sites appeared to be essential to the AF elimination. It suggests that CFAEs may contribute to the initiation of some AF. ATP may be useful to induce AF after proven PV isolation, and further ablation might be necessary to ensure efficacy after circumferential PV isolation.