Association of Trypanosoma cruzi genotypes, immune response and cardiac arrhythmias in patients with the chronic phase of Chagas disease

• Grant number: 25/15706-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2025
• End date: September 30, 2026
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Henrique Turin Moreira
• Grantee: Livia Alves Guimarães
• Host Institution: Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da USP (HCMRP). Ribeirão Preto , SP, Brazil

Abstract

Chagas cardiomyopathy remains a disease with incompletely elucidated pathogenic mechanisms, despite affecting approximately 30-40% of individuals infected with Trypanosoma cruzi (1-2 million carriers in Brazil). Although myocarditis induced by persistent parasitic infection is widely accepted as the underlying cause of cardiac lesions, the substantial clinical variability among patients suggests the presence of additional modulatory factors. In this context, the discrete typing units (DTUs) of T. cruzi have emerged as potential determinants of distinct immune-inflammatory response profiles and, consequently, specific cardiac manifestations such as arrhythmias. This retrospective study will evaluate 175 adults with chronic Chagas disease, previously genotyped at HCFMRP-USP using multiplex PCR across multiple molecular markers, compared to reference controls for each genotype. We will investigate the association between T. cruzi DTUs, the magnitude of the immune response (quantified by chemiluminescence), and the occurrence of arrhythmias documented through clinical history, resting electrocardiogram, and 24-hour Holter monitoring. The study will classify supraventricular arrhythmias (fibrillation and flutter), ventricular arrhythmias (sustained and non-sustained), atrial and ventricular extrasystoles, as well as sinus and atrioventricular conduction disorders warranting permanent pacemaker implantation. By exploring genotypic differences in the parasite as potential modulators of arrhythmic phenotypes, this project aims to clarify the role of DTUs in the clinical heterogeneity of Chagas heart disease. The findings may support risk stratification strategies and targeted interventions for arrhythmias in patients with Chagas disease.