Hemodynamic effects of clonidine in patients with heart failure during exercise

To determine the hemodynamic effects after inhibition of the increased sympathetic activity in patients with heart failure, 14 patients were given the central acting sympathetic inhibitor, clonidine. orally. Clonidine 75-150 vg reduced the heartrates, blood pressure, double products (HR.BPa), systemic vascular resistance and pulmonary vascular resistance, wbile the cardiac output, cardiac index and stroke volume index increased only in severe patients. Exercise-induced increase of heart rates, HR.BPs products. pulmonary artery end-diastolic pressure and pulmonary vascular resistance were attenuated after clonidine, but the stroke volume index increased. It is shown that the decrease of vascular resistance and cardiac oxygen consumption are the acute resting hemodynamic effects of clonidine. and after oral clonidine the left ventricular performance curve shifts leftward during exercise.