Chagas disease is considered by the World Health Organization (WHO) as one of the most neglected tropical diseases in the world, having relevance in many Latin America countries. In addition, it already affects North America, Europe, Asia and Oceania. Some studies suggest that chagasic heart failure has a worse prognosis, with up to 50% shorter survival than other etiologies. The PARADIGM-HF (Prospective Comparison of Angiotensin Receptor Blocker-Neprilysin Inhibitor With Angiotensin-Converting Enzyme Inhibitor to Determine Impact on Global Mortality and Morbidity in Heart Failure) study showed 20% reduction in mortality comparing sacubitril/valsartan with the standard treatment with ACE (angiotensin converting enzyme) inhibitors. In the scenario of chagasic cardiomyopathy, a post hoc analysis of PARADGIM-HF was reported on 113 patients. Reduced risk of cardiovascular death or hospitalization for HF was noted in the group treated with sacubitril/valsartan. Attention was drawn the study's limitations that included the small number of patients and reduced statistical power. Therefore, the benefit of this new class remains uncertain in heart failure due to Chagas cardiomyopathy. The ANSWER-HF Trial will be a clinical, randomized, single-center, prospective, double-blind, controlled study. It will include 200 consecutive participants with Chagas cardiomyopathy and left ventricular ejection fraction less than 40% randomized independently. The objective of this study is to evaluate the benefit of sacubitril/valsartan compared with enalapril in patients with heart failure due to Chagas cardiomyopathy, with reduced ejection fraction. The primary endpoint of the study is the change of left ventricular ejection fraction determined by transthoracic echocardiography. Secondary endpoints include: assessment of ventricular arrhythmias; evaluation of functional class; assessment of functional capacity; assessment of ventricular remodeling; and evaluation of biomarkers. The patients will be followed for 6 months after treatment start. All patients will be undergone to Doppler Echocardiography, 24-hour Holter, 6-minute walk test, Biochemical and hematological exams and Biomarkers at the baseline and after 6 months.