In patients with history of sustained ventricular tachycarrhythmias, the efficacy and safety of
moricizine have not been systematically evaluated by electrophysiological studies. We performed electrophysiological testing in these patients in the
drug-free state and then after
moricizine loading, and evaluated the safety profile of
moricizine during in-hospital loading and follow-up. The study population comprised of 31 patients with clinically sustained
ventricular tachyarrhythmia. The underlying
heart disease was coronary in 25 patients,
cardiomyopathy in 5 patients, and none in 1 patient. The left ventricular (LV) ejection fraction ranged from 15%-69% (mean 39 +/- 15%). During the baseline
drug-free electrophysiological testing, sustained
ventricular tachycardia was inducible in 27 patients,
ventricular fibrillation in 1 patient, and reproducible,
nonsustained ventricular tachycardia (15-25 sec) in 3 patients. All 31 patients received
moricizine to the maximum tolerated dose (851 +/- 185 mg) over a period of 2-7 days. Six patients developed ventricular proarrhythmia within the first 4 days. Proarrhythmia required multiple
cardioversions in three patients, was not associated with QT prolongation, and spontaneously resolved 6-24 hours after withdrawal of
moricizine. Of the remaining 25 patients, 24 underwent electrophysiological testing on
moricizine and 4 patients (16%) were rendered noninducible. The VT cycle length in the other 20 patients slowed from 243 +/- 30 msec to 299 +/- 60 msec (P < 0.09). Four noninducible patients, two patients with inducible but slowed VT and one patient who had refused further testing were discharged on
moricizine.(ABSTRACT TRUNCATED AT 250 WORDS)