(A) Rest electrocardiograph during sinus rhythm with right bundle branch block and intracardiac recording of AH-HV interval through a catheter at the His bundle region. (B) Twelve-lead electrocardiograph of clinical bundle-branch reentry ventricular tachycardia. (C) Induction of ventricular tachycardia, with evidence of H-H interval driving V-V interval. (D) Three-dimensional anatomical map of left ventricle (right anterior oblique view). Red arrows show left ventricle potentials of left bundle branch.