AimsPrior reports using pacing manoeuvres, demonstrated an up to 42% prevalence of residual pulmonary vein to left atrium (PV–LA) exit conduction after apparent LA–PV entry block. We aimed to determine in a two-centre study the prevalence of residual PV–LA exit conduction in the presence of unambiguously proven entry block and without pacing manoeuvres.Methods and resultsOf 378 patients, 132 (35%) exhibited spontaneous pulmonary vein (PV) potentials following circumferential PV isolation guided by three-dimensional mapping and a circular mapping catheter. Pulmonary vein automaticity was regarded as unambiguous proof of LA–PV entry block. We determined the prevalence of spontaneous exit conduction of the spontaneous PV potentials toward the LA. Pulmonary vein automaticity was observed in 171 PVs: 61 right superior PV, 33 right inferior PV, 47 left superior PV, and 30 left inferior PV. Cycle length of the PV automaticity was >1000 ms in all cases. Spontaneous PV–LA exit conduction was observed in one of 171 PVs (0.6%). In a subset of 69 PVs, pacing from within the PV invariably confirmed PVLA exit block.ConclusionUnidirectional block at the LA–PV junction is unusual (0.6%). This observation is supportive of LA–PV entry block as a sufficient electrophysiological endpoint for PV isolation.

In selected low TE risk patients undergoing ablation for AF, a short period of periprocedural therapeutic anticoagulation with LMWH together with aspirin is an effective and safe strategy to prevent TE events. If confirmed in a randomized trial, this approach might simplify periprocedural antithrombotic management in ablation of selected AF patients.

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