Chronic chagasic cardiomyopathy (CCC) is a public health problem still without a defined physiopathology. It results from a chronic infection by Trypanosoma cruzi and is characterized by irreversible lesions to the heart. The contribution of autoimmune processes to cardiac dysfunctions observed in CCC has been hypothesized by several authors [1–3]. Those studies demonstrated the presence of IgG components in sera of patients with CCC and dilated cardiomyopathy interacting with cardiac β1-adrenergic (anti-β1-AR) and muscarinic membrane receptors (anti-M2-CR) [3].