[Alcohol and myocarditis].

Abstract

The direct toxic effect of alcohol and its metabolite acetaldehyde has been demonstrated both in laboratory animals and in humans. Alterations in the mitochondrial ultrastructure and the dilatation of the sarcoplasmatic reticulum have been shown after an acute infusion of alcohol in the heart. These changes correlate with decreased mitochondrial function, defects in protein synthesis and the occurrence of arrhythmias. The risk of developing alcoholic cardiomyopathy is related to both the mean daily alcohol intake and the duration of drinking, but there is much individual susceptibility to the toxic effect of alcohol. Most patients, in whom alcoholic cardiomyopathy develops, have been drinking over 80 g/d for more than 5 years. The clinical diagnosis of alcoholic cardiomyopathy reflects the coexistence of global myocardial dysfunction in a heavy drinker in whom no other cause for myocardial disease was found. In studies focussing on alcoholic cardiomyopathy the surprising histologic findings in endomyocardial biopsy in about 30% of all cases was myocarditis with a lymphocytic infiltrate in association with myocyte degeneration or focal necrosis. In myocarditis, the network of microtubules and intermediate filaments is also disrupted by the inflammatory reaction which involves resident cells (myocytes, fibroblasts, endothel cells) and systemic cells (granulocytes, macrophages, monocytes, lymphocytes). Changes in the cardiac cytoskeleton and the extracellular matrix may affect contractile function, since the cytoskeleton organizes the intra- and intercellular architecture. After all, in patients with alcohol abuse and myocarditis the immune functioning appears to be compromised. Several studies suggest that heavy drinking alters both lymphocyte and granulocyte production and function. Alcohol consumption per se might harm the immune system. Furthermore, the myocardial damage due to alcohol consumption could initiate autoreactive mechanisms comparable to those in viral or idiopathic myocarditis. Patients with alcohol abuse and myocarditis have a poor prognosis: signs of biventricular failure including tachycardia, hepatomegaly, and peripheral and lung edema are observed. These symptoms are as nonspecific as are various echocardiographic and electrocardiographic changes such as atrial and ventricular arrhythmias which may be associated both with myocarditis, alcoholic cardiomyopathy and acute effects of drinking without hemodynamic alterations. For the management of patients with alcohol abuse the prevention of further alcohol intake is mandatory to reverse the myocardial damage and the unfavorable predisposition for infection. Specific treatment of myocarditis is the second important option, and treatment of heart failure by reducing the size of the dilated heart and alleviating the signs and symptoms of heart failure is a logical third step.