Plasma norepinephrine concentration in the coronary sinus in cardiomyopathies

In order to evaluate the cardiac sympathetic nerve tone in cardiomyopathies, plasma norepinephrine concentration in the coronary sinus (NE(CS)) and artery (NE(A)) was measured by THI method in five patients with the hypertrophic type (HCM) and in seven with the congestive type (CCM); six patients with functional murmur served as controls. NE(CS) was 182 +/- 39 ng/liter (SEM) in HCM, 288 +/- 47 in CCM, and 306 +/- 65 in controls. The NE(CS) - NE(A) difference (delta NE) was 9 +/- 22 ng/liter in HCM, -57 +/- 34 in CCM, and 81 +/- 29 in controls. Norepinephrine overflow into the coronary sinus,which was calculated by multiplying coronary sinus plasma flow by delta NE, was 0.54 +/- 0.86 ng/min/100gm, -2.81 +/- 1.47, and 3.73 +/- 1.77, respectively. Norepinephrine overflow and delta NE were significantly lower in CCM than in controls. The results suggest than an excessive sympathetic discharge does not exist in HCM and that cardiac sympathetic activity is reduced in CCM.