[Is urapidil a venodilator?]

This study aimed to assess and compare the effects of urapidil and clonidine on right ventricular volumes and function in 20 physical status ASA III patients, with a borderline untreated essential hypertension and with or without chronic coronary artery disease. The patients were randomly assigned to two equal groups to receive either urapidil (0.4 mg.kg-1) or clonidine (2.5 micrograms.kg-1). Neither patient had congestive heart failure, valvular heart disease, previous myocardial infarction, nor was any being treated with beta-blocking agents or with amiodarone. Usual anti-anginal medication (nifedipine and isosorbide) was maintained up to the time of the procedure. Monitoring was obtained from ECG, Swan-Ganz catheter fitted out with a fast response-thermistor, and radial artery cannula. Blood samples were withdrawn for plasma atrial natriuretic factor determination. Thirty minutes after catheter insertion, baseline data were collected in supine and 45 degrees head-up tilt positions. Following urapidil or clonidine i.v. injection, three series of measurements (3, 8 and 13 min) were made in supine and tilt positions according to a randomized sequence. The two groups were similar with regard to age, weight, height, coronary artery disease and treatment. Urapidil and clonidine elicited a similar decrease in mean arterial pressure of 14% in supine position and 20% in head-up tilt position, combined with an exclusive decrease in systolic index i.e. not associated with a change in peripheral vascular resistances. Despite the decrease in arterial pressure, heart rate remained unchanged. Right ventricular ejection fraction was maintained after both urapidil and clonidine, however end-diastolic and end-systolic volumes decreased, with no modification by tilting.(ABSTRACT TRUNCATED AT 250 WORDS)