Combined therapy with digoxin and nitroprusside in heart failure complicating acute myocardial infarction

Abstract

The hemodynamic effects of digoxin plus nitroprusside were compared with those of nitroprusside alone in 11 patients with congestive heart failure complicating acute myocardlal infarction. Hemodynamic measurements were made using a Swan-Ganz thermodilution catheter and a bedside thermodilution cardiac output computer. Patients received increasing doses of nitroprusside until mean arterial pressure decreased to 70 mm Hg or pulmonary arterial wedge pressure decreased to 16 mm Hg. The infusion rate of nitroprusside was then held constant for 120 minutes. After 30 minutes of constant nitroprusside infusion, 0.5 mg of digoxin was given intravenously. Hemodynamic measurements were obtained before treatment with nitroprusside and immediately before and 30, 60 and 90 minutes after the administration of digoxin. Nitroprusside produced a significant decrease in pulmonary arterial wedge pressure (24 to 16 mm Hg), mean arterial pressure (92 to 85 mm Hg and systemic vascular resistance (1,816 to 1,480 dynes sec cm −5) and a significant increase in cardiac index (2.19 to 2.51 liters/min per m 2). Ninety minutes after the administration of digoxin, cardiac index was further increased (2.51 to 28.2 liters/min per m 2, P = 0.03) and systemic vascular resistance was tower (1,480 to 1,320 dynes sec cm −5, P = 0.03). Pulmonary arterial wedge pressure was not further decreased by the addition of digoxin. Thus, the addition of digoxin further increases cardiac output in patients with congestive heart failure complicating myocardial infarction who are receiving nitroprusside but does not produce any further decrease in pulmonary arterial wedge pressure.