Acute and Subacute Haemodynamic Effects of Enalapril

After a run-in period on placebo, 15 patients with primary hypertension got antihypertensive treatment with enalapril single therapy during six weeks. Before and four hours after drug administration simultaneous non-invasive recordings of ECG, phonocardiogram and carotid pulse tracing or apexcardio-gram or impedance cardiogram were made. After six weeks' therapy the recordings were repeated 12 hours and four hours after dose intake. The results showed enalapril to be a potent antihypertensive agent with considerable effect already four hours after the first dose intake. The blood pressure reduction was explained by a decrease in total peripheral resistance, semiquantitatively measured with impedance cardiography. Cardiac output was significantly higher during long-term treatment than betore therapy started, due to a significant increase in stroke volume. Lef ventricular (LV) diastolic function was not altered but a considerable improvement in LV systolic function was achieved as judged from the systolic time intervals. Open questioning regarding side effects indicated good tolerance.