Reduced response of cardiac norepinephrine release to isometric handgrip exercise in heart failure

In order to evaluate the relation of cardiac norepinephrine (NE) release to left ventricular function, blood was taken simultaneously from the coronary sinus (CS) and the aorta (A) in 19 patients with heart diseases, at rest and during isometric handgrip exercise (IHG) at 30% of their maximal contraction. Plasma NE was analyzed by Renzini's THI method. The concentrations of plasma NE at rest were 397 +/- 66 (S.E.M.) ng/liter in CS and 292 +/- 50 in A. IHG significantly increased NE to 578 +/- 88 in CS and to 462 +/- 85 in A (p less than 0.001). Estimated NE release from the heart (deltaNE = NECS - NEA) correlated inversely to left ventricular end-diastolic pressure at rest (r = -0.520, p less than 0.05) and during IHG (r= -0.689, p less than 0.01). The changes in deltaNE induced by IHG correlated to the slope of the left ventricular function curve (r=0.618, p less than 0.01). It is concluded that the response of cardiac NE release to exercise is reduced in patients with depressed cardiac function.