The clinical and electrophysiological characteristics of nonsustained repetitive monomorphic ventricular tachycardia from the left His-Purkinje system.

BACKGROUND: Repetitive monomorphic ventricular tachycardia (RMVT) arising from the left His-Purkinje system can occasionally be encountered during clinical practice. We describe eight cases as a unique entity in this study to characterize the clinical and electrophysiological features of the patients. METHODS: Eight patients with frequent palpitation (five men with median age of 28 years) were included in the study from January 2003 to July 2018. Twelve-lead ECG (Electrocardiogram), Holter, and echocardiographic tests were performed after medical history interrogations and physical examinations. Antiarrhythmic drug therapy was essential to all patients, and catheter ablation was attempted if the patients could not tolerate or were not responsive to drug therapy. RESULTS: No patients had a history of syncope and a family history of sudden cardiac death. ECGrecording was characterized by frequent ventricular extrasystoles, ventricular couplets, and salvos of nonsustained VT competitive with sinus rhythm. The QRS morphology of ectopic beats was in the right bundle branch block pattern with severe left axis deviation. The width of the QRS complex from ECG was 135 ms (120-140) during ventricular tachycardia. Verapamil had no effect on all VT individuals. Enlargement of the left ventricle was found in two patients. Four out of six cases were successful with catheter ablation treatment. CONCLUSION: RMVT arising from the left His-Purkinje system is a special arrhythmic and nonverapamil-sensitive entity. The electrophysiological mechanism of this treatment appears to be focal firing, which is amendable to catheter ablation in symptomatic and high-burden patients.