Pre- and afterload reduction in chronic mitral regurgitation: a double-blind randomized placebo-controlled trial of the acute and 2 weeks' effect of nifedipine or isosorbide dinitrate treatment on left ventricular function and the severity of mitral regurgitation.

1 The acute effect and effect of 14 days' treatment with isosorbide dinitrate (ISDN) and nifedipine (NIF) was evaluated by radionuclide cardiography in patients with chronic mitral regurgitation and sinus rhythm. 2 In 23 patients with clinically stable disease blood pressure was lowered by 15% and left ventricular volume was reduced by 16-20% after 20 mg sublingual ISDN causing combined pre- and afterload reduction. Afterload reduction alone induced by 10 mg NIF resulted in an acute 9% decrease in left ventricular endsystolic volume, whereas forward stroke volume increased by 30%, and regurgitation fraction tended to decrease. No haemodynamic effects could be detected after 14 days' treatment with 20 mg ISDN orally twice daily (preload reduction), whereas 20 mg NIF twice daily (afterload reduction) caused an increase in forward stroke volume (18%) and a decrease in both regurgitant volume (20%) and regurgitation fraction (22%) without affecting blood pressure or heart rate. 3 ISDN and NIF have beneficial acute haemodynamic effects in patients with chronic mitral regurgitation probably due to their pre- and afterload reducing properties. The reduction in regurgitation induced by NIF appears to be sustained after 14 days therapy.