Electrophysiological evaluation of moricizine in patients with sustained ventricular tachyarrhythmias: low efficacy and high incidence of proarrhythmia.
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)
Bhandari
A K
AK
Heart Institute, Hospital of the Good Samaritan, Los Angeles, California.
Lerman
R
R
Ehrlich
S
S
Sager
P
P
Leon
C
C
Widerhorn
J
J
Cannom
D S
DS
D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016293:Moricizine / Q000009:adverse effects / Q000627:therapeutic use*; D017180:Tachycardia, Ventricular / Q000188:drug therapy* / Q000503:physiopathology
D016293:Moricizine