HLA-A and heart failure: It was found that 13 out of 50 chagasic patients (26%) were HLA-A2+; from whom all were HLA-A*0201+, classified as six chronic patients in indeterminate phase or A stage (normal electrocardiography ECG, and no major findings arising during clinical examination) and seven symptomatic chagasic patients having different disease severity levels as follows: 2 B (abnormal ECG results), 3 C (abnormal ECG results, decreased left ventricular ejection fraction, LVEF, and cardiac enlargement) and 2 D (abnormal ECG results, cardiac enlargement, decreased LEFV, and clinical signs of heart failure).