Catheter ablation of idiopathic exercise-induced right bundle branch block and left axis deviation ventricular tachycardia.

Catheter ablation of ventricular tachycardia was performed in a patient without evidence of structural heart disease. ECG showed ventricular tachycardia and a right bundle branch block QRS configuration with left axis deviation induced by exercise and atrial pacing. At electrophysiology, presystolic activation was found in the low septal region of the left ventricle. Radiofrequency energy delivered to this site failed to prevent tachycardia. Three direct current shocks (total energy 400 J) delivered in this region rendered the tachycardia noninducible. There were no complications. During the follow-up period of six months the patient has remained free from arrhythmia on no medication. This report expands the use of catheter ablation to patients with idiopathic ventricular tachycardia ('verapamil responsive' ventricular tachycardia) originating in the left ventricle.