Repetitive monomorphic ventricular tachycardia (Gallavardin type): clinical and electrophysiological characteristics in 20 patients

Abstract

Repetitive monomorphic ventricular tachycardia (RMVT) is defined by the presence of numerous monomorphic isolated, premature ventricular complexes, couplets, and runs of unsustained ventricular tachycardia having the same morphology in patients without structural heart disease. Patients with RMVT mostly demonstrate the typical left bundle branch block morphology with normal or rightward axis during tachycardia. At our institution, 20 patients with RMVT have been systematically studied: a syncope had occurred in 35% of our patients, in three cases a syncope was the first manifestation of the RMVT. Of our RMVT patients, 25% developed sustained episodes (> 3 min) of ventricular tachycardia as documented by Holter ECG. The salvos of ventricular tachycardia are generally short in RMVT. This behavior and the typical exercise dependence differentiates RMVT from paroxysmal sustained idiopathic ventricular tachycardia. Exercise testing is mandatory for correct diagnosis of RMVT. In our institution, 85-90% of RMVT patients demonstrated runs of ventricular tachycardia or sustained ventricular tachycardia while on a treadmill (exercise test) or during isoproterenol infusion. RMVT was inducible by programmed electrical right ventricular stimulation in only 13% of our patients. Therefore, in patients with suspected RMVT programmed electrophysiological stimulation is only useful to differentiate a ventricular tachycardia from a supraventricular tachycardia with bundle brunch block or in patients with unexplained syncope. The prognosis is considered generally good; in our patients no life threatening ventricular tachyarrhythmias were observed during a follow-up of up to 4 years. Verapamil and beta-adrenoceptor antagonists generally offer symptomatic improvement. In some cases treatment with a class III antiarrhythmic agent is necessary. While drug-refractory paroxysmal sustained idiopathic ventricular tachycardia can be abladed with both immediate and long-term success, catheter ablation of RMVT is only rarely indicated.