Dilatation of the pulmonary veins in atrial fibrillation: a transesophageal echocardiographic evaluation.

Ectopic beats originating from sleeves of atrial tissue within the pulmonary veins (PVs) can induce and sustain paroxysmal atrial fibrillation (AF). Left atrial stretch and dilatation favors the development of atrial ectopy and AF. Similarly, PV dilatation, if present, might trigger PV ectopy in patients with AF.