The main trunk of the left bundle branch is not part of the re-entry circuit of verapamil-sensitive idiopathic left ventricular tachycardia

Abstract

We report the case of a 19-year-old man with verapamil-sensitive idiopathic left ventricular tachycardia (ILVT), who had paroxysmal palpitations for 3 years. Programmed right atrial and ventricular stimulation easily induced ventricular tachycardia (VT) with QRS duration of 125 ms, right bundle branch block pattern, and right inferior axis, which are characteristics of ILVT. Left ventricular endocardial mapping accidentally produced a complete left bundle branch block and provoked prolongation of the QRS duration of VT, which was 143 ms. However, no changes occurred in the cycle length, inducibility, or maintenance of VT. The VT was eliminated successfully by catheter ablation at the pre-Purkinje potential (PP) recording site. These findings suggest that the main trunk of the left bundle branch is not a critical component of the re-entry circuit of ILVT.

Keywords

• Verapamil-sensitive idiopathic left ventricular tachycardia
• Left main bundle branch
• Left bundle branch block
• Ventricular tachycardia circuit
• Left ventricular mapping