Abnormal left ventricular response to isometric exercise in pure, isolated aortic regurgitation: beneficial effects of nifedipine.

To examine the effects of nifedipine on the left ventricular (LV) functional response to isometric exercise in patients with aortic regurgitation (AR), 20 patients with isolated, moderate to severe AR performed 3 minutes of handgrip exercise at 33% of their maximal voluntary contraction, before and after administration of 20 mg of sublingual nifedipine. Although handgrip exercise produced similar increases in heart rate and systolic blood pressure before and after nifedipine treatment, heart rate was higher and systolic blood pressure lower with handgrip exercise during nifedipine treatment. LV end-diastolic volume index was not different during the control period and nifedipine handgrip exercise, but the increase in end-systolic volume index was smaller and the ejection fraction was higher during nifedipine handgrip exercise. Nifedipine reduces afterload and ameliorates handgrip exercise-induced LV dysfunction in patients with AR.