The mechanism by which atrial fibrillation is initiated in patients with accessory pathways is not fully understood. Retrograde conduction of ventricular premature beats to the atrium, causing the arrhythmia, is a very rare cause. We report a patient with Wolff-Parkinson-White syndrome (WPW), without previous tachycardias, who presented multiple episodes of paroxysmal atrial fibrillation after having a myocardial infarction. During the electrophysiological (EP) study the patient presented two spontaneous episodes of atrial fibrillation initiated by ventricular premature beats conducted to the atria through the accessory pathway. After successful catheter ablation of the accessory pathway the patient did not present arrhythmia recurrences.