The objective of the present study was to study the morphological criteria for toxic cardiopathy with the use of histological and immunohistochemical methods. The results of immunohistochemical studies of the sinoatrial node---???---(SAN) and the working myocardium in the patients presenting with alcoholic cardiomyopathy (ACMP) are presented. It was shown that vimentin expression in the SAN structures and the contractile myocardium is slightly increased whereas the expression of sarcomeric actin is decreased and that of fibrinogen is increased too. The authors put forward an assumption about the role of lesions in the membrane apparatus of the pacemaker cells in the development of arrhythmia characteristic of tanatogenesis associated with alcoholic cardiomyopathy.