Key result
Intravenous disopyramide phosphate lowered resting cardiac index (4.0 vs 4.3 L/min/m2, P<0.05) and increased left ventricular end-diastolic pressure, but cardiac index rose normally during exercise.
Why the study?
Does intravenous disopyramide alter hemodynamic parameters at rest and during exercise in patients without heart disease?
Does intravenous disopyramide alter hemodynamic parameters at rest and during exercise in patients without heart disease?
Absolute Event Rate: 4% vs 4.3%
p-value: p=<0.05
Disopyramide causes mild depression of left ventricular function at rest but preserves normal hemodynamic responses during exercise in patients without heart disease.
Disopyramide may mildly impair resting hemodynamics while preserving exercise response in patients without heart disease; hypothesis-generating from a single case and should not change practice.
The hemodynamic effects of disopyramide phosphate, 2.0 mg/kg body weight, given intravenously over a period of five minutes were studied at rest and during exercise in ten patients without clinical or angiographic evidence of heart disease. Following disopyramide, the resting cardiac index was lower (4.0 +/- 0.6 vs 4.3 +/- 0.6 liters/min/m2, mean +/- 1 SD,P less than 0.05), while left ventricular end-diastolic pressure (16 +/- 4 vs 11 +/- 4 mm Hg, P less than 0.001), pulmonary arterial (PA) mean pressure (20 +/- 5 vs 17 +/- 5 mm Hg, P less than 0.05), and brachial arterial (BA) mean pressure (105 +/- 8 vs 96 +/- 7 mm Hg, P less than 0.05), were higher than the pre-infusion resting values. During exercise, there was no change in left ventricular end-diastolic pressure while cardiac index rose from 4.0 +/- 0.6 to 6.5 +/- 0.6 liters/min/m2 (P less than 0.001) and left ventricular stroke work index increased from 62 +/- 19 to 84 +/- 22 gm/beat/m2 (P less than 0.001). The normal hemodynamic response during exercise after disopyramide despite the apparent depression of left ventricular function at rest probably reflects the positive inotropic effect of enhanced sympathoadrenergic activity.
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Thadani et al. (1981) studied normal subjects (n=10). disopyramide phosphate vs. pre-infusion resting values was evaluated on resting cardiac index (liters/min/m2) (p=<0.05). Intravenous disopyramide phosphate lowered resting cardiac index (4.0 vs 4.3 L/min/m2, P<0.05) and increased left ventricular end-diastolic pressure, but cardiac index rose normally during exercise.
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