Afterload reduction with nifedipine in aortic insufficiency.

The acute hemodynamic effects of nifedipine were assessed in 12 patients with severe aortic insufficiency during control conditions and 30 minutes after administration of nifedipine (20 mg sublingually). Left ventricular end-diastolic pressure decreased from 19 +/- 8 (mean +/- standard deviation) to 9 +/- 5 mm Hg (probability [p] less than 0.0001), mean aortic pressure from 98 +/- 12 to 80 +/- 9 mm Hg (p less than 0.00001), systemic vascular resistance from 1,135 +/- 280 to 794 +/- 176 dynes . s. cm-5 (p less than 0.0002) and rate-pressure product from 11,732 +/- 1,727 to 10,022 +/- 1,103 mm Hg beats/min (p less than 0.01). Forward cardiac index increased by 24 percent, from 3.8 +/- 1.1 to 4.4 to 0.8 liters/min per m2 (p less than 0.04). Left ventricular end-diastolic volume, ejection fraction and total stroke work index did not change significantly. Regurgitant fraction, measured in five patients, changed parallel with systemic vascular resistance. Left ventricular function was maintained while both preload and afterload were decreased. Regurgitant flow was moderated and myocardial oxygen demand decreased. This hemodynamically favorable condition, due to nifedipine, is clinically important and suggests the need for further therapeutic trials.