[Ventricular reentry tachycardia within the bundle branches. Report of 3 cases].

Vientricular tachycardia due to reentry within the bundle branches occurs in the presence of left ventricular dilatation and conduction alterations in the His-Purkinje system. A macro-reentry is formed by the His bundle, left and right bundles and ventricular myocardium. The anatomical substrate of this arrhythmia is ventricular dilatation. However, it may appear in healthy hearts. Alterations of intraventricular conduction are reflected by a prolongation of PR interval and bundle branch block in the surface EKG and prolongation of HV interval in the endocavitary registry. During tachycardia, His activation precedes ventricular activation. We report three patients aged 55, 58 and 78 years old with a dilated cardiomyopathy and ventricular tachycardia due to reentry within the bundle branches. All had a left bundle branch block and a prolonged HV internal. The arrhythmia was induced during the study in two patients. All were subjected to radiofrequency fulguration of the right branch of the His bundle. After fulguration, two remained with a pattern of complete right bundle branch block and one with a complete intermittent AV block. All three are free of arrhythmic events.