[The importance of the endothelium in heart failure]

The endothelium is involved in cardiac and vascular dysfunction characteristic of heart failure. Vascular dysfunction has been related either to an impaired endothelium dependent vasodilation of both capacitance and resistance vessels, or to an increase in the plasmatic levels of endothelium derived contracting factors, such as endothelin-1. While the former seems to respond favourably to ACE-inhibitors, physical training and L-arginine; the latter will soon be treatable with endothelin-1 A e B receptor antagonists or with inhibitors of its converting enzyme. Cardiac dysfunction may be explained not only by the loss of the positive inotropic effect induced by low concentrations of nitric oxide (produced by the constitutive NO-synthase in the normal endothelium), but also by the negative inotropic effect induced by the high concentrations of nitric oxide, produced as a consequence of the stimulation of the inducible NO-synthase. It is therefore conceivable that cardiac dysfunction would also improve with the administration of drugs presently used to correct endothelium dependent vasodilatation disturbances.