An atypical atrial flutter of focal origin: a study using a noncontact mapping system.

We report a case of focal atrial tachycardia with appearance suggestive of atypical atrial flutter in a 57-year-old man. Based on ECG criteria, tachycardia was misclassified as atypical atrial flutter. The electrophysiological study using a noncontact mapping system revealed a focal activity within the left upper pulmonary vein ostium. This case highlights the limitations of standard electrocardiographic and electrophysiological classifications of regular atrial tachycardia. This report also shows the relevance of new mapping techniques in the successful mapping and ablation of these arrhythmias, even those arising within the left atrium.