Does oral disopyramide phosphate reduce the frequency of cardiac ectopic depolarizations compared to placebo in outpatients with arrhythmias?
Disopyramide phosphate is an effective and well-tolerated oral antiarrhythmic agent for reducing ectopic depolarizations and ventricular arrhythmias in outpatients.
The efficacy of disopyramide phosphate (DP), a new oral antiarrhythmic agent, was evaluated by serial ten hour, portable electrocardiographic monitoring during placebo (P) and DP administration. In this 16 week outpatient study, DP therapy reduced the frequency of all cardiac ectopic depolarizations (ED) in 10 of 17 patients (average occurrence: P 145 per hour and DP 4 per hour, p < 0.05). Further, ventricular arrhythmias (VA): ventricular tachycardia (VT), and complicated VED, were recorded during P in 8 of 17 and in 16 of 17 patients, respectively, but this prevalence diminished with DP administration (VT 1 of 17, P < 0.05; VED 10 of 17 patients, p < 0.05). Atrial tachycardia (AT), noted in 6 patients during P, was abolished in 4 during active drug treatment. Despite minor anticholinergic adverse effects in 6 patients, DP was well tolerated in 17 of 18 patients and appeared safe even in 5 patients with cardiac decompensation prior to its administration.
Vismara et al. (Thu,) studied this question.
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