The patient is a 60-year-old female with functional class III/ IV (NYHA) heart failure of an immunomediated etiology (autoimmune myocarditis). After unsuccessful therapeutic attempts, intravenous immunoglobulin was used, leading to deterioration in renal function, a rare complication of that therapy. After hemodialysis, the patient's renal function was restored, and the chronic heart failure improved to functional class I.Myocardites constitute a group of diseases characterized by immuno-inflammatory aggression against the myocardium. The anatomicopathological substrate of this aggression has been classically described as a cellular infiltration of lymphocytes, macrophages, and other leukocytes, with destruction of cardiomyocytes, myocytolysis (Dallas criteria) 1 . In past years, advances in understanding of the complex pathophysiology of the disease and low sensitivity of the histopathological criteria have forced us to widen the model of aggression to beyond the immune response of the classical cellular type (Th1). Currently, we believe that an immunomediated aggression against the myocardium occurs, even when the infiltration of immunologic cells is absent. The characterization of pathogenic autoantibodies specific for more than a dozen autoantigens has led us to a new model 2 . The etiology of those diseases is still obscure. Activation of the immunologic system is known to occur, resulting in different forms of myocardial injury. The pathogenic stimuli that lead to the development of that cardiospecific aggression are yet to be elucidated.The current major hypothesis is based on the model of viral infection as the promoter of the immune reaction directed against the heart. Different types of viruses, such as coxsackievirus, parvovirus, adenovirus, cytomegalovirus, Epstein-Barr virus, and parvovirus B19, have often been implicated. However, most clinical studies have shown great variability and low positivity in evidencing the viruses 1 . Other clinical phenomena, such as skin diseases (eg, psoriasis and vitiligo), systemic autoimmune diseases, and even intestinal diseases, such as celiac disease, have been significantly associated with myocardites, suggesting, therefore, a wide and complex pathophysiological model 3 .The clinical findings of myocardites are highly varied. Their symptoms may range from fever and malaise to cardiac symptoms, such as palpitation, dyspnea, and chest pain. The physical examination, and laboratory and radiological findings are not specific, making the diagnosis difficult, which requires an elevated clinical suspicion.The most accurate noninvasive diagnostic method is indium-111 antimyosin myocardial scintigraphy 4 . This technique is not available in our country. However, another technique of nuclear medicine that uses gallium 67, a marker of inflammation, has been used despite its lower sensitivity and specificity.The endomyocardial biopsy, using Dallas histopathologic criteria, has been the standard diagnostic method, despite its low sensitivity. That technique has been boosted...