Noninvasive study of cardiac structure and function after rilmenidine for essential hypertension

The hemodynamic effects of rilmenidine (S 3341) were evaluated noninvasively by aortic Doppler velocimetry, M-mode echocardiography and phonocardiography in hypertensive patients treated for 28 days. After a 2-week placebo run-in period, patients with mild hypertension (group I, n = 8, mean diastolic blood pressure [BP] = 97.18 +/- 0.65 mm Hg) received 1 mg of rilmenidine each morning and patients with moderate hypertension (group II, n = 6, mean diastolic BP = 107.62 +/- 1.18 mm Hg) received 1 mg twice daily. The hemodynamic variations in both groups after the first administration (day 1) showed that during the first 3 hours, mean arterial pressure and cardiac index (CI) were significantly reduced, whereas total peripheral resistance (TPR) was increased. From the third to the fifth hour, the decrease in mean arterial pressure was maintained, CI was higher than initial values and TPR decreased, indicating a persistent vasodilator effect. On day 28, hemodynamic variations were similar but of a lower amplitude. Before administration on day 28, a significant decrease in systolic and diastolic BP was observed, demonstrating that the antihypertensive activity of 1 mg was maintained for 24 hours, with a significant reduction in TPR and no modification of CI or stroke index. The M-mode and phonocardiographic left ventricular function indexes remained unchanged. Rilmenidine has a prolonged antihypertensive activity with a chronic vasodilator effect and no negative inotropic effect.