REPETITIVE MONOMORPHIC VENTRICULAR-TACHYC ARDIA (TYPE GALLAVARDIN) - CLINICAL AND ELECTROPHYSIOLOGIC CHARACTERISTICS IN 20 PATIENTS

Repetitive monomorphic ventricular tachycardia (RMVT) is defined by th e presence of numerous monomorphic isolated, premature ventricular com plexes, couplets, and runs of unsustained ventricular tachycardia havi ng the same morphology in patients without structural heart disease. P atients with RMVT mostly demonstrate the typical left bundle branch bl ock morphology with normal or rightward axis during tachycardia. At ou r institution 20 patients with RMVT have been systemically 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% dev eloped sustained episodes (> 3 min) of ventricular tachycardia as docu mented by Holter EGG. The salves of ventricular tachycardia are genera lly short in RMVT. This behavior and the typical exercise dependence d ifferentiates RMVT from paroxysmal sustained idiopathic ventricular ta chycardia. Exercise testing is mandatory for correct diagnosis of RMVT . In our institution 85-90% of RMVT patients demonstrated runs of vent ricular tachycardia or sustained ventricular tachycardia while on a tr eadmill (exercise test) or during isoproterenol infusion. RMVT was ind ucible by programmed electrical right ventricular stimulation in only 13% of our patients. Therefore, in patients with suspected RMVT progra mmed electrophysiological stimulation is only useful to differentiate a ventricular tachycardia from a supraventricular tachycardia with bun dle brunch block or in patients with unexplained syncope. The prognosi s is considered generally good; in our patients no life threatening ve ntricular tachyarrhythmias were observed during a follow-up of up to 4 years. Verapamil and P-adrenoceptor antagonists generally offer sympt omatic improvement. In some cases treatment with a class III antiarrhy thmic agent is necessary. While drug-refractory paroxysmal sustained i diopathic ventricular tachycardia can be abladed with both immediate a nd long-term success, catheter ablation of RMVT is only rarely indicat ed.