Studies of the rat heart in sequential sets of alcoholic animals: 5% ethanol ingestion (9.5% total calories/day/for 25 weeks); 10% ethanol for 45 weeks; and 25% ethanol (31% total calories/day/for 26 weeks), revealed ultrastructure abnormalities comprising swelling of mitchondria, transverse tubules and sarcoplasmic reticulum with disintegration of myofibrils; concomitant depression of myofibrillar ATPase activity and decreased cardiac mitochondrial respiration; and alterations of isometric contractile performance of left ventricular papillary muscles. These studies, indicating that chronic daily intake of ethanol representing 10 to 30% of total calories exerts toxic effects in microstructure, metabolism and mechanics of the heart, are to be extended to experimental animal evaluation of cardiac pump performance by the isolated whole heart preparation with greater ethanol consumption; protective role of vitamins; reversibility of structural, metabolic and functional cardiac changes after alcohol withdrawal; and assessment of sarcoplasmic reticulum and excitation-contraction coupling by calcium uptake and binding studies. Elucidation of these mechanisms are pertinent to the pathogenesis and management of alcoholic cardiomyopathy in patients. BIBLIOGRAPHIC REFERENCES: Segel, L.D., Chacko, K., Amsterdam, E.A., and Mason, D.T.: Alcohol and the heart: Acute effects and mechanisms of cardiomyopathy. In: Cardiovascular Problems (Ed.: H. Russek),Univ. Park Press, Baltimore, pgs. 409-418, 1976. Mason, D.T., Miller, R.R., DeMaria, A.N., Segel, L.D. and Amsterdam, E.A.: Management of chronic refractory congestive heart failure. In: Congestive Heart Failure: Mechanisms, Evaluation and Treatment (Ed.: D. Mason) York Medical Books, New York City, pgs. 293-312, 1976.