The first part of the study deals with the early diagnosis of cardiomyopathies on the ground of physical examination of the patients and of his ECG and X-ray finding. It is stressed, that in the majority of cases already this set of examination can in the physicial of the first contact awake a suspicion of cardiomyopathy. Further precision of diagnosis demands examination in a cardiological center where the facilities for cardiac catheterization, angiography and coronarogrpahy are available. The second part of the study deals with the problem of mechanism of the early heart failure in caridomyopathies. Studying the structural, metabolic and functional changes of the heart muscle in the dietetic, catecholamine and alkoholic model of experimental cardiomyopathy, the authors came to the conclusion that the main factor in this pathological event is disturbance of the oxidative process and thus of the energy generation at the subcellular level in the heart muscle. This metabolic disturbance is progressively leading to morphological changes and to a weaking of the contractile power of the heart muscle.