Why the study?
Does disopyramide reduce left ventricular systolic function in normal subjects?
Does disopyramide reduce left ventricular systolic function in normal subjects?
Oral disopyramide significantly depresses left ventricular systolic function in normal subjects, with effects correlating with plasma drug concentrations.
May warrant caution with disopyramide in systolic dysfunction; leaves open effects in clinical populations pending randomized data.
We used M-mode echocardiography and recordings of systolic time intervals to follow changes in left ventricular systolic function of 10 normal subjects during administration of 200 mg oral disopyramide every 8 h. Left ventricular function was significantly depressed (peak rate of change of dimension - 17%, p less than 0.001; mean velocity of circumferential fiber shortening - 15%, p less than 0.01; percent fractional shortening - 16%, p less than 0.05) for as long as 7 h after a dose. These changes could be correlated with those in plasma concentrations of free and total disopyramide, and of its mono-N-dealkylated metabolite (change in peak rate of change of dimension versus levels of disopyramide plus metabolite, r = -0.41, p less than 0.03; changes in ratio preejection time/ejection time versus levels of disopyramide and metabolite, r = 0.62, p less than 0.002).
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Holt et al. (1983) studied this question.
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