CARDIAC SYMPATHETIC INNERVATION IN PATIENTS WITH DILATED CARDIOMYOPATHY - IMMUNOHISTOCHEMICAL STUDY USING ANTI-TYROSINE HYDROXYLASE ANTIBODY

Depletion of norepinephrine in the left ventricular myocardium in case s of dilated cardiomyopathy (DCM) has been suggested. However, there h ave been few histological studies of the sympathetic nerves, in which myocardial norepinephrine is believed to exist. We performed an immuno histological study of the density of tyrosine hydroxylase (TH, a marke r of sympathetic nerves)-positive nerve fiber in endomyocardial biopsy specimens in cases of DCM using antibody against TH. TH-positive nerv es were stained brown along with the myocardium, and they were more de nse in the right ventricle than in the left ventricle in both the DCM and control groups. The density of TH-positive nerves in cases of DCM was significantly less than that in the control group in the subendoca rdial myocardium of the right and left ventricles, but especially in t he left ventricle. A correlation was observed in the DCM group between the density of TH-positive nerves and the ejection fraction in the ri ght ventricle, but not in the left ventricle. In the failing human hea rt, a decrease in subendocardial sympathetic nerve density may be one of the causes of myocardial norepinephrine depletion.