The authors report three cases of acute myocarditis: the first patient was a 23 year old woman treated for tuberculosis who presented with rapidly progressive congestive cardiac failure. The second patient was a 52 year old man with atypical chest pain and the third was a 55 year old woman presenting as an acute myocardial infarction. In all three cases, a positive antimyosin antibody myocardial scintigraphy supported the presumptive diagnosis. The authors review the principles of the method and its potential indications, antimyosin antibody scintigraphy being able to demonstrate recent myocardial necrosis but not to identify the cause. The sensitivity of the technique is high (83 to 100% according to the series) but the specificity is much lower (about 55%) compared with endomyocardial biopsy, an investigation which is specific but not very sensitive. Modifications of the antibody and the radioactive tracer used at present should improve the diagnostic value of the technique in the near future.