ELEVATED PLASMA ENDOTHELIN CONCENTRATIONS IN HEART-FAILURE - AN EFFECT OF ANGIOTENSIN-II

Endothelin is a powerful vasoconstrictor that may be partly responsibl e for the increases in venous and arterial tone characteristic of hear t failure. The release of endothelin from endothelial cells in culture is stimulated by angiotensin II. We investigated the relationship bet ween plasma concentrations of immuno reactive endothelin-1 and angiote nsin II in 25 patients with heart failure and eight with ischaemic hea rt disease but normal left ventricular function. Plasma concentrations of endothelin and angiotensin II were correlated (Spearman rank corre lation coefficient of 0.72; P<0.0001) in patients with heart disease. Plasma concentrations of angiotensin II and endothelin were higher in those patients with heart failure. Angiotensin II was infused over a 3 h period in eight healthy volunteers. Infusion of angiotensin II incr eased plasma concentrations of angiotensin II to levels greater than t hose usually found in patients with severe heart failure but induced o nly a modest rise in plasma concentrations of immunoreactive endotheli n-1 (0.77 +/- 0.16 to 1.03 +/- 0.03 pmol . l-1, P<0.02). Increased pla sma concentrations of angiotensin II and endothelin-1 both appear to r eflect the presence and severity of heart failure. Although a signific ant correlation exists between plasma concentrations of angiotensin II and endothelin in patients with heart failure, the relationship may n ot be causal.