The right ventricular tachycardias.

A variety of tachycardias originate from the right ventricle or use right ventricular structures as part of their circuit. They are characterized by a left bundle branch block pattern. Many of these tachycardias are relatively easy targets for radiofrequency catheter ablation. Ventricular tachycardia (VT) is the most common manifestation of arrhythmogenic right ventricular dysplasia, an often familial disease that can cause sudden death. Catheter ablation, antiarrhythmic drugs, or an implantable cardioverter-defibrillator may be used as therapy. Idiopathic right ventricular tachycardia has a benign course. It most often arises from the septal region of the right ventricular outflow tract. It commonly presents as nonsustained, repetitive monomorphic VT. The success rate of catheter ablation is greater than 90%. Bundle branch reentry occurs in patients with cardiomyopathy and His-Purkinje disease. It uses the right bundle branch anterogradely and the left bundle branch retrogradely. The QRS is very similar during VT and sinus rhythm. It can be cured by catheter ablation of the right bundle branch. VT seldom originates from the right ventricle in patients with coronary artery disease, idiopathic cardiomyopathy, or myocarditis. Atriofascicular (so-called Mahaim) fibers can sustain antidromic AV reentrant tachycardia. They represent an accessory AV node and His-Purkinje-like conduction system with atrial insertion in the right free wall near the tricuspid annulus and distal insertion directly into the right bundle branch. The accessory connection is ablated at the level of the tricuspid ring.