Catheter ablation of bundle branch reentrant ventricular tachycardia.

Bundle branch reentrant ventricular tachycardia (BBR-VT) is a form of macroreentrant tachycardia involving the bundle of His, both bundle branches, and the ventricular myocardium in the circuit. It generally occurs in the background of dilated cardiomyopathy, prior valve surgery, or other cardiac disease with an underlying His-Purkinje system (HPS) disease. Clinically, BBR-VT usually results in marked hemodynamic compromise and often presents with syncope, presyncope, or sudden cardiac arrest. When a ventricular tachycardia is induced, the presence of His deflections preceding every ventricular deflection should alert one to the possibility of this entity. It is important to show that oscillations in the H-H cycle length results in variations in V-V cycle length. Entrainment of the tachycardia from atrium and right ventricular apex and characteristics of postpacing intervals can be used to differentiate this arrhythmia from intramyocardial reentry and supraventricular tachycardia with aberrancy. Right bundle branch ablation usually cures the tachycardia, and recurrence is uncommon. The underlying cardiac disease and ventricular dysfunction dictate the prognosis and choice of device therapy in these patients.