Two-to-one conduction block between left atrium and right lower pulmonary vein preceding complete vein isolation during radiofrequency current ablation.

A 56-year-old patient with paroxysmal atrial fibrillation who developed a transient 2:1 block between the left atrium and right inferior pulmonary vein during a single application of radiofrequency current was described. The production of transient and complete atriovenous block by a single application of radiofrequency current demonstrates that a single connection between the pulmonary veins muscle and the left atrium may exist.