Suppression of concealed pulmonary vein bigeminy by atrial pacing in a patient with paroxysmal atrial fibrillation.

Concealed pulmonary vein bigeminy, as a pair of a pulmonary vein spike potential within a fragmented far-field atrial electrogram and a premature ectopic pulmonary vein spike potential with exit block, was continuously recorded in a patient with paroxysmal AF. Atrial pacing suppressed the breakthrough from the left atrium to the pulmonary vein, thus preventing the conducted and the premature ectopic pulmonary vein potentials. Atrial pacing induced conduction block between the left atrium and the arrhythmogenic pulmonary vein might be a possible explanation for the prevention of paroxysmal AF by atrial pacing.