The exact pathophysiological function of ß1AdrRab remains unclear and conflicting results exist about their effects on cardiac function: Nagatomo et al. showing favorable effects of IgG3 anti-β1AR Ab in HF (12, 13) whilst most other publications report a mainly negative influence of anti-β1AR Ab, especially in cardiomyopathy related to Chagas disease (14). This evidence concerns the gene ADRB1 and Chagas disease.