Recently, Scott and Saphir1reported two cases of acute isolated myocarditis, which were the first to be recorded in the American literature. They mentioned the reports of thirty-six other cases with postmortem observations recorded in the Continental literature since 1888, when Steffen2described two cases of acute myocarditis which probably fall into this classification. Fiedler,3however, in 1890 was the first to give a clear description of the disease, and it is his name that has served as an eponym since. There are many synonyms in use in labeling this type of lesion. A few of the terms used by previous authors are "interstitial," "circumscribed," "diffuse," "isolated," "idiopathic" and "primary," singly or in combination. The terms refer to an inflammatory lesion of the myocardium alone, which is associated with a distinctive clinical and pathologic picture. Sellentin4was the first to name the disease isolated myocarditis because, as a rule, changes