Persistent, isolated pulmonary vein re-entry: inducibility, entrainment, and overdrive termination of a sustained tachycardia within an isolated pulmonary vein.

Pulmonary veins (PVs) are the predominant sources of paroxysmal atrial fibrillation (AF), and electrical PV isolation has become an established interventional treatment for patients suffering from AF. There are a few cases describing PV tachycardias; however, mechanisms of PV arrhythmogenicity resulting in PV tachycardias remain incompletely understood. We report on a patient who underwent PV isolation for paroxysmal AF, in whom a persistent PV tachycardia was observed within an isolated vein. This tachycardia was stable in nature and different pacing manoeuvres revealed electrophysiological features consistent with reentry (Lasso displaying the entire tachycardia cycle length, concealed entrainment, overdrive termination, and induction by programmed stimulation) as the underlying mechanism.