Unique Conduction of Left-Lateral Accessory Pathway: A Case Report

Abstract

A 77-year-old man was admitted to our hospital because of palpitation and dyspnea. The twelve-lead electrocardiogram showed the irregular wide QRS tachycardia. During the sinus rhythm, there were no ventricular preexcitation and no abnormal findings on the twelve-lead electrocardiogram. We performed the electrophysiological study. There was no conduction over the accessory pathway during the high right atrial and ventricular pacing. Venous injection of adenosine could also make the atrio-ventricular conduction block. However, coronary sinus pacing (pacing cycle length=330 ms) could make the antegrade conduction over the left-lateral accessory pathway, and this QRS complex was quite similar to clinical one. We diagnosed his clinical wide QRS tachycardia was preexcited atrial fibrillation. This accessory pathway was eliminated by radiofrequency application. He remained free of any arrhythmias after the procedure.