[Comparison of the efficacy of 2 delayed-action preparations of hydroquinidine and quinidine in the prevention of pacing induced ventricular tachycardia].

The effects of two antiarrhythmic agents, hydroquinidine and quinidine on the prevention of pacing induced sustained ventricular tachycardia (VT) were studied in 14 patients. The underlying cardiac disease was old myocardial infarction (12 patients) or dilated cardiomyopathy (2 patients). Sustained monomorphic VT was induced in 14 patients during the initial electrophysiological study performed at least 48 hours after withdrawal of all antiarrhythmic therapy. The same stimulation protocol including 3 extrastimuli (S2 S3 S4) and 2 paced cycles (600 ms and 400 ms) was repeated at least 48 hours after the administration of 600 mg (2 gelules) per 24 hours of hydroquinidine or 1100 mg of quinidine arabogalactane sulphate, 3 to 4 hours after the last dose. This was an open, randomised, crossed over trial. Irrespective of the result observed with the first antiarrhythmic, used in an order attributed by a randomised table, the other antiarrhythmic was tested. Plasma concentrations were measured during the programmed stimulation test for both drugs. Induced VT was prevented by the two antiarrhythmics in 4 patients (28%). In one patient, VT was prevented by hydroquinidine but not by the quinidine compound, resulting in a prevention rate of 35% for the hydroquinidine. On the other hand, the quinidine compound was a total success in one patient in whom only a partial success was observed with hydroquinidine. VT remained inducible with both antiarrhythmics in 9 patients (64%).(ABSTRACT TRUNCATED AT 250 WORDS)