Relationship between plasma endothelin-1 levels and myocardial ischemia induced by exercise testing

A substantial increase in circulating levels of endothelin-1 in humans has been demonstrated in the early hours of acute myocardial infarction(1) and in some, but not all, patients with unstable angina.(2) Myocardial infarction and unstable angina are complex pathophysiologic states characterized by coronary hypoperfusion, hypoxia, thrombin generation, catecholamine release, and a different degree of myocardial necrosis, all factors that may enhance the secretion of endothelin-1 from endothelial cells.(3-5) The present study was undertaken to assess whether myocardial ischemia itself could result in increased endothelin-1 plasma levels. Accordingly, circulating endothelin-1 concentrations were measured in patients with effort angina and objective signs of myocardial ischemia during exercise. A group of patients with effort angina also, but without inducible ischemia during exercise, served as controls.