Rate‐dependent and unidirectional conduction block between the left pulmonary vein and left atrium after catheter ablation for atrial fibrillation

A 77‐year‐old woman with symptomatic paroxysmal atrial fibrillation (PAF) underwent pulmonary vein isolation (PVI), but subsequently experienced recurrence. In the second session, unidirectional left atrium (LA)‐left superior pulmonary vein (LSPV) conduction was revealed to exist at the carina of the LSPV. Left pulmonary vein (LPV) pacing performed in a cycle between 300 and 260 ms revealed rate‐dependent pulmonary vein (PV)‐LA conduction, and the location was estimated to be in the roof of the LSPV. PV isolation was achieved after ablation of two gaps. Consideration of the presence of rate‐dependent gaps may be useful to confirm bidirectional block lines after ablation.