Hemodynamic comparison of primary venous or arteriolar dilatation and the subsequent effect of furosemide in left ventricular failure after acute myocardial infarction.

The hemodynamic effect of venous dilatation (intravenous isosorbide dinitrate [ISDN]) and arteriolar dilatation (intravenous hydralazine), both as firstline treatment and then combined with intravenous furosemide, were evaluated in a randomized, between-group comparison in 20 men with severe acute left-sided cardiac failure after myocardial infarction (MI). Both ISDN (50 to 200 micrograms/kg/hour) (Group 1) and hydralazine (0.15 mg/kg) (Group 2) reduced systemic arterial pressure (p less than 0.05) and vascular resistance (p less than 0.05). Pulmonary artery occluded pressure was reduced (p less than 0.01) only by ISDN, whereas heart rate (p less than 0.01), cardiac output (p less than 0.01) and stroke volume (p less than 0.05) were increased only after hydralazine. After ISDN, furosemide (1 mg/kg) decreased left-sided cardiac filling pressure by 1 mm Hg (p greater than 0.05), whereas after hydralazine, furosemide in a similar dose reduced pulmonary artery occluded pressure by 5 mm Hg (p less than 0.01). In both groups of patients, furosemide transiently increased systemic arterial pressure (p less than 0.05). Cardiac output was reduced (p less than 0.05) and systemic vascular resistance increased (p less than 0.05) in Group 1 patients after furosemide. Similar changes in both variables in Group 2 patients did not attain statistical significance. In conclusion, ISDN-induced venous dilatation is preferable to primary arteriolar dilatation by hydralazine as first-line treatment in acute left-sided cardiac failure. However, hydralazine and furosemide in combination were equally effective in reducing pulmonary artery occluded pressure and increasing cardiac output. The influences of each regimen on prognosis await further investigation.

RCT Entities:   Population Interventions Outcomes