Vasodilator therapy in acute myocardial infarction. A comparison of sodium nitroprusside and nitroglycerin.

Twenty-six patients with complicated acute myocardial infarction were studied in order to compare the hemodynamic effects of sodium nitroprusside (NP) and nitroglycerin (GTN). All patients received NP and 18 of the 26 also received GTN to evaluate both drugs in the same individuals. Both agents produced significant declines in mean arterial pressure, total peripheral resistance (TPR), and heart rate systolic blood pressure product. However, in the 18 patients who received both drugs GTN produced a greater fall (P less than 0.05) in pulmonary capillary wedge pressure (PCW) (25 to 15 mm Hg) than did NP (24 to 17 mm Hg) and a greater increment (P less than 0.01) in (see article) (0.98 to 1.43) than NP (0.98 to 1.16). These data confirm the potent vasodilatory effects of NP and GTN and suggest that NP has a relatively balanced effect on the arterial and venous circulation, and GTN seems to produce more potent venodilatation than arterial dilatation. These observations provide a basis for a more rational choice of vasodilator agents based on initial hemodynamic measurements in complicated acute myocardial infarction.