Although atrial fibrillation is usually caused by multiple circulating reentrant wavelets, a focal origin has recently been reported. This focal source could be successfully treated by discrete radiofrequency catheter ablation. We report a patient without structural heart disease, but with multiple episodes of palpitations related to atrial premature beats, irregular atrial tachycardia and atrial fibrillation. The electrophysiological study demonstrated that all the atrial arrhythmias were due to the same focus firing irregularly and exhibiting a unique and centrifugal pattern of activation. Successful radiofrequency catheter ablation of the focus was performed, without complications. After three months follow-up the patient is asymptomatic and she has not presented arrhythmia recurrences.