[Acute myocarditis and eosinophilic pneumonia: good outcome after medical treatment and long-term follow-up].

The authors report a case of acute eosinophilic myocarditis (AEM) with acute left ventricular failure preceded by an acute hypoxaemic eosinophilic pneumonia. The diagnosis of myocarditis was confirmed histologically. That of the eosinophilic pneumonia was base on the abundance of eosinophilic polynuclear cells in the bronchoalveolar lavage and appearances on computerised tomography. The pulmonary lesions rapidly and definitely regressed and complete recovery of left ventricular function was obtained by long-term steroid therapy. This favourable outcome has been sustained after 11 years of follow-up despite the presence of chronic mild hypereosinophilia. In the absence of specific clinical and paraclinical data, the diagnosis of AEM was based on the demonstration of an inflammatory infiltrate rich in polynuclear eosinophils and necrotic myocardial lesions. This histological signature may be obtained in vivo by endomyocardial biopsy, the indication of which must be rapidly recognised. Only the instauration of early and intensive steroid therapy seems to influence the outcome which is frequently poor. The synthesis of the anatomo-clinical and experimental data suggests a myocardial aggression by cytotoxic effects of granular protein components released during activation of polynuclear eosinophils. The role of AEM is discussed in the different aspects of cardiac hypereosinophilia.