WIDE COMPLEX TACHYCARDIA WITH ATRIOVENTRICULAR DISSOCIATION AND QRS MORPHOLOGY IDENTICAL TO THAT OF SINUS RHYTHM - A MANIFESTATION OF BUNDLE-BRANCH REENTRY

Objective-To determine the features that distinguish bundle branch ree ntry (BBR) ventricular tachycardia from a supraventricular tachycardia with aberration on the 12 lead electrocardiogram (EGG). Patients-Thre e patients in whom premature beats (2 cases) or sustained tachycardia (2 cases) showed a QRS configuration identical to that observed during sinus rhythm. Interventions-Programmed electrical stimulation. Result s-These arrhythmias were ventricular in origin and caused by a BBR mec hanism, as suggested by the following data obtained during electrophys iological study: (a) an H-V interval shorter during tachycardia than d uring sinus rhythm; (b) A-V dissociation; (c) activation of the right bundle branch before activation of the bundle of His. The ECG of all 3 patients showed right bundle branch block with very prolonged QRS dur ation (0.16 to 0.20 s). Characteristically, all 3 had prolonged H-V in terval during sinus rhythm. All patients had had a previous myocardial infarction and had a dilated left ventricle. Conclusion-The presence of (a) wide complex extrasystoles or tachycardia with a QRS morphology identical to that of sinus rhythm; (b) A-V dissociation; and (c) a ve ry prolonged QRS duration (0.16 s or more) is suggestive of ventricula r tachycardia caused by bundle branch reentry.