A randomized comparison between the hemodynamic effects of hydralazine and nitroglycerin alone and in combination at rest and during isometric exercise in patients with chronic mitral regurgitation.

Both arteriolar vasodilation with hydralazine and venodilation with nitroglycerin have been shown to favorably alter the hemodynamic profile in patients with chronic mitral regurgitation. Since these therapeutic modalities exert their effects by different mechanisms, this study was designed to assess hemodynamic response to both drugs given individually and in combination at rest and during isometric exercise in patients with chronic mitral regurgitation of various etiologies. When used individually, hydralazine caused larger increase in heart rate, cardiac index, stroke volume index, and systemic vascular resistance both at rest and during exercise. In contrast, nitroglycerin administration was associated with a superior effect on mean pulmonary artery pressure and V wave amplitude at rest and on mean right atrial and mean pulmonary artery wedge pressures at rest and during isometric exercise. In comparison with hydralazine alone, combination therapy enhanced the reduction in right atrial pressure (4 +/- 1 versus 0 +/- 2 mm Hg, p < 0.05), mean pulmonary arterial pressure (11 +/- 5 versus 1 +/- 3 mm Hg, p < 0.05), and the V wave amplitude (15 +/- 6 versus -5 +/- 3 mm Hg, p < 0.05) at rest and resulted in a larger reduction in exercise values of mean pulmonary artery pressure (-11 +/- 7 versus -3 +/- 5 mm Hg, p < 0.05) and mean pulmonary arterial wedge pressure (-11 +/- 5 versus -5 +/- 3 mm Hg, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)