Acute effects of urapidil on left ventricular function in hypertensive patients: comparison with clonidine using radionuclide angiography.

We have studied the effects of urapidil 0.4 mg kg-1 i.v. and clonidine 2.5 micrograms kg-1 i.v. on left ventricular volume and function in 20 patients with chronic coronary artery disease and essential hypertension. Patients were studied using 99mtechnetium radionuclide angiography with first-pass and ECG-gated equilibrium blood-pool techniques and non-invasive sphygmomanometry. Administration of both urapidil and clonidine caused a similar decrease in mean arterial pressure (20%), associated with an equivalent reduction in systemic vascular resistance. Despite the decrease in mean arterial pressure, heart rate did not change after administration of clonidine, but there was an early and transient increase of 13% after urapidil. There were no changes in cardiac index, but in contrast with clonidine, urapidil caused a decrease in stroke index. In both groups, global left ventricular ejection fraction did not change. Urapidil produced a mean decrease in end-diastolic volume of 8% and a mean decrease in end-systolic volume of 13%, in contrast with clonidine which caused little change. Reduced arterial pressure, systemic vascular resistance and preload after urapidil 0.4 mg kg-1 i.v., associated with lack of prolonged tachycardia and preserved global left ventricular performance, may have obvious clinical implications in anaesthesia.