Idiopathic myopathies are disorders characterized by inflammatory muscle damage. However, it has also been found that they may present significant muscle heart engagement, even with the development of heart failure. This is a frequent cause of morbidity and mortality in this group of patients. In this regard, the case of a 54 year old female patient with initial suspicion of acute coronary syndrome accompanied by polymyositis, chest pain and commitment of the ejection fraction, is presented. (Acta