Effect of Nitroprusside on Left Ventricular Dynamics in Mitral Regurgitation

In order to evaluate the circulatory action of vasodilator therapy in patients with significant mitral regurgitation, sodium nitroprusside was infused intravenously in 14 patients who had mitral regurgitation due to a variety of causes. In 13 of these patients, valvular insufficiency had been present for several years. The mean arterial pressure fall from 88 ± 1.2 to 71 ± 2.1 mm Hg was accompanied by a significant decrease in pulmonary artery pressure (from 27.4 ± 2.7 to 19.1 ± 2.4 mm Hg), pulmonary artery wedge v wave (from 31.7 ± 3.3 to 17.0 ± 1.9 mm Hg), and left ventricular end-diastolic pressure (from 16.7 ± 1.6 to 9.3 ± 1.2 mm Hg). In 10 patients significant decreases in angiographic end-diastolic volumes (from 196 ± 10 to 177 ± 10 ml) and end-systolic volumes (from 90 ± 10 to 77 ± 9 ml) were accompanied by slight decreases in the total stroke volume and slight increases in the ejection fraction. The improved forward stroke volume index (from 27 ± 3.0 to 33 ± 2.1 ml) was due to a very significant reduction in the regurgitant fraction (from 57 ± 6 to 42 ± 6%). Nitroprusside, therefore, has beneficial hemodynamic effects in patients with chronic mitral regurgitation.