Idiopathic Premature Ventricular Contraction Originating from Left Epicardial Outflow Tract —Effects of Antiarrhythmic Drugs, Autonomic Provocation and Radiofrequency Catheter Ablation—

We present a patient with frequent episodes of palpitation who had idiopathic premature ventricular contraction (PVC. with QRS morphology exhibiting a right bundle branch block pattern with an inferior axis. Neither administration of procainamide, propranolol, lidocaine or verapamil could inhibit PVC, whereas administration of adenosine triphosphate, carotid sinus massage and Valsalva maneuver could effectively eliminate PVC. The earliest activation preceding the QRS complex by 25 msec at occurrence of the PVC was recorded at the distal site of the coronary sinus and within the left coronary cusp. Pacemapping in the supravalvular site during sinus rhythm produced a QRS complex more similar to PVC than that produced in the infravalvular site of the left ventricular outflow tract (LVOT). Radiofrequency catheter ablation was performed at the supravalvular site close to the epicardial LVOT, which resulted in successful elimination of PVCs.