In 16 patients with chronic
aortic regurgitation, we studied the acute hormonal and hemodynamic effects of 12.5 to 25 mg
captopril; in 12 patients the changes after a 4 to 8 week treatment period (mean 6.3 +/- 2 weeks; doses: 3 times 12.5 to 3 times 25 mg/day) were investigated. The following baseline variables were evaluated: the
radionuclide left ventricular ejection fraction (EF) at rest and during exercise, left ventricular end-diastolic volume (EDV), regurgitant blood volume (RBV); and plasma
renin activity (PRA). Repeated determinations of EF, EDV and RPA were carried out 90 minutes after application of the
drug. In patients with chronic
therapy, EF at rest and during exercise, EDV, RBV and PRA were reinvestigated at the end of the study. Acute administration of
captopril was followed by an increase of EF (from 49 +/- 12 to 55 +/- 12%, p less than 0.001) and a slight decrease of EDV (from 389 +/- 160 to 376 +/- 146 ml, p less than 0.05). PRA significantly increased (from 1.6 to 3.1 ng/ml/h, p less than 0.05). Chronic
therapy resulted in a moderate decrease of systolic and diastolic blood pressure (from 156/70 +/- 31/15 to 140/63 +/- 23/15 mm Hg, p less than 0.01). However, no significant changes were observed in EF at rest and during exercise (51 +/- 9 vs. 53 +/- 10% and 45 +/- 14 vs. 47 +/- 14%), EDV (433 +/- 179 vs. 422 +/- 179 ml) and RBV (136 +/- 81 vs. 129 +/- 77 ml). PRA was significantly increased (6.3 ng/ml/h, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)