Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Background: Cardiomyopathy in systemic lupus erythematosus (SLE) may be secondary to myocardial inflammation (i.e. myocarditis) or to systemic complications such as hypertension. Symptomatic left ventricular dysfunction is the most common clinical presentation of cardiomyopathy and is potentially life threatening. Identifying the cause is critical as it dictates therapy. Methods: We present three cases of left ventricular failure suggestive of myocarditis in SLE patients followed in the Lupus Clinic of the Montreal General Hospital over a 5-year period. Results: The most frequent presentation is acute onset of a marked reduction of the left ventricular ejection fraction (LVEF). All patients were treated with cardiac support, prednisone, and additional immunosuppressive medications. Improvement of symptoms and LVEF was observed in two of three patients. Conclusion: Myocarditis is a rare, but life-threatening, manifestation of SLE. With immunosuppressive medications and cardiovascular support, the long-term outcome is usually favorable. Lupus (2011) 20, 981-988.209981988Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2008/02917-0, 2009/06049-6]CNPq [300447/2009-4]