Surgical Correction of Anomalous Left Ventricular Pre-excitation: Wolff-Parkinson-White (Type A)

This report describes two patients with the Wolff-Parkinson-White syndrome including episodes of supraventricular tachycardia and atrial fibrillation. Both patients had Type A electrocardiograms. Electrophysiological studies demonstrated pre-excitation and evidence that the site of pre-excitation involved the left ventricle. The effective refractory periods of the accessory pathway during atrioventricular conduction were 240 and 220 msec respectively. Epicardial mapping at the time of surgery showed that anomalous excitation began adjacent to the annulus of the mitral valve near a marginal branch of the left circumflex coronary artery. An incision which separated the atrial muscle from the annulus of the mitral valve at the region of anomalous excitation abolished the delta wave. Epicardial maps after surgery showed normal ventricular activation and follow-up studies have shown normal electrocardiograms and no arrhythmias.