Polymorphic Ventricular Tachycardias with Involvement of the His-Purkinje System in Non-Ischemic Cardiomyopathy

Abstract

Ventricular tachycardia (VT) associated with the His-Purkinje system has been infrequently reported in patients with structural heart disease. A 69-year-old man presented with nausea and diaphoresis. ECG showed wide QRS tachycardia with a right bundle branch block configuration as right axis deviation, 240 bpm. The tachycardia was temporarily terminated with verapamil but reinitiated and required several electrical cardioversions. Coronary angiography revealed no significant stenosis and left ventricular ejection fraction 34%. He underwent electrophysiological study to make a diagnosis of wide QRS tachycardia. When a ventricular tachycardia was induced, the presence of His deflections preceded every ventricular deflection and oscillations in the H-H cycle length resulted in variations in V-V cycle length. This suggested the possibility of the His-Purkinje entity. During the VT, the diastolic potential (DP) was recorded at the anteroseptal left ventricle. Changes in the QRS morphology were associated with the time between DP and onset of QRS complex (V), and prolongation of DP-V interval terminated the VT. Different exits from relatively large area of slow conduction around the left ventricular base area might have produced the polymorphic VTs. In addition, the delayed potentials were seen during sinus rhythm around this area. We report this case of a patient who had non-ischemic cardiomyopathy and developed Purkinje reentrant polymorphic VT.