Effects of low-dose adrenomedullin on cardiac function and systemic haemodynamics in man

The cardiovascular effects of low-dose adrenomedullin (ADM, 1, 2 and 3 pmol kg(-1) min(-1) for 30 min each) were evaluated in six healthy subjects in a placebo controlled, cross-over study by determining cardiac volumes, syst olic and diastolic function (echocardiography) and systemic haemodynamics b efore, during and after ADM or placebo. High-resolution ultrasound was used to evaluate changes in carotid artery distension. ADM caused a +85% increm ent in its plasma levels and significantly increased plasma cyclic adenyl m onophosphate (cAMP). Compared with placebo, ADM induced significant decreme nts in left ventricular (LV) systolic diameter and systemic vascular resist ance, and increments in LV posterior wall thickening, ejection fraction and cardiac index. Right and left atrial emptying fraction and carotid artery distention increased. LV diastolic function, heart rate, and plasma renin a ctivity did not change, whereas packed cell volume increased. These results indicate that ADM influences cardiovascular function and systemic haemodyn amics at physiological plasma levels in man mainly because of its vasodilat ing activity, leading to reduced afterload.