Cardiac involvement in polymyositis and dermatomyositis usually is asymptomatic and rarely the principal clinical feature at the time of initial presentation. We describe a patient with dermatomyositis who presented with overt acute pericarditis which has not, to our knowledge, been previously reported. Acute pulmonary edema resulting from documented acute myocarditis developed during a second exacerbation. Long-term follow-up failed to demonstrate new cardiac complications during subsequent exacerbations, adding to the known polymorphism of the heart involvement in these systemic disorders.