1/4 Revista da Sociedade Brasileira de Medicina Tropical Journal of the Brazilian Society of Tropical Medicine Vol.:54 | (e0047-2021) | 2021 https://doi.org/10.1590/0037-8682-0047-2021 Corresponding author: Dr. Vanessa Pereira Lima. e-mail: vanessa.lima@ufvjm.edu.br  https://orcid.org/0000-0002-0349-3248 Received 28 January 2021 Accepted 3 September 2021 www.scielo.br/rsbmt I www.rsbmt.org.br Short Communication Determinants of minute ventilation–carbon dioxide production relationship in Chagas cardiomyopathy Lucas Frois Fernandes Oliveira [1] , Janaina Martins Andrade [2],[3] , Pedro Henrique Scheidt Figueiredo [1],[2] , Matheus Ribeiro Ávila [1] , Whesley Tanor Silva [1] , Marcus Vinicius Accetta Vianna [2],[3] , Renato Guilherme Trede Filho [1],[2] , Henrique Silveira Costa [1],[2] , Manoel Otávio Costa Rocha [4] and Vanessa Pereira Lima [1],[2] [1]. Universidade Federal dos Vales do Jequitinhonha e Mucuri, Departamento de Fisioterapia, Diamantina, MG, Brasil. [2]. Universidade Federal dos Vales do Jequitinhonha e Mucuri, Programa de Pós-Graduação em Reabilitação e Desempenho Funcional, Diamantina, MG, Brasil. [3]. Universidade Federal dos Vales do Jequitinhonha e Mucuri, Faculdade de Medicina, Diamantina, MG, Brasil. [4]. Universidade Federal de Minas Gerais, Curso de Pós-graduação em Infectologia e Medicina Tropical, Belo Horizonte, MG, Brasil. Abstract Introduction: The minute ventilation–carbon dioxide production relationship (VE/VCO 2 slope) is among the main prognostic factors of Chagas cardiomyopathy whose determinants remain unknown. Methods: Seventy-eight patients with Chagas cardiomyopathy were evaluated using clinical assessment, cardiopulmonary exercise test, echocardiography, and International Physical Activity Questionnaire. Results: Age, functional class, International Physical Activity Questionnaire score, and dilated cardiomyopathy with systolic dysfunction were independent determinants of VE/VCO 2 slope, and these variables explained 63% of its variance. Conclusions: The VE/VCO 2 slope was related to age, functional class, physical activity level, and dilated cardiomyopathy with systolic dysfunction in patients with Chagas cardiomyopathy. Keywords: Chagas cardiomyopathy. Chagas disease. Exercise test. Chagas disease is defned as an acute or chronic infectious condition caused by the protozoan Trypanosoma cruzi. An estimated 6–7 million people are infected by the parasite worldwide, mostly in Latin America. Up to 30% of chronically infected people will develop cardiac abnormalities due to Chagas disease 1 . The cardiac form, Chagas cardiomyopathy (ChC), is the most common and severe clinical manifestation of the disease in which patients usually develop thromboembolism, malignant arrhythmias, and heart failure 2 . In ChC, even in the early stages of cardiopathy, intense fatigue, progressive dyspnea, and reduced functional capacity 3 contribute to exercise intolerance. The cardiopulmonary exercise test (CPET) is the gold standard for assessing functional capacity. In patients with heart failure, peak oxygen uptake (VO 2peak ) provides important clinical information. However, in recent decades, other CPET variables have demonstrated a strong prognostic value in these patients, such as the relationship between ventilation (VE) and carbon dioxide production (VCO 2 ) expressed as the VE/VCO 2 slope 4 . In a review, Arena, Myers, and Guazzi 5 reported that an elevated VE/VCO 2 slope was linked to ventilation–perfusion abnormalities. The authors also demonstrated that the VE/VCO 2 slope and VO 2peak were the most well-established predictors of mortality in patients with heart failure. In the setting of ChC, Ritt et al. 6 reported that the VE/VCO 2 slope was the only independent predictor of a worse prognosis (cut-of value of 32.5) among the variables evaluated by the CPET. However, unlike heart failure, few studies have evaluated the VE/VCO 2 slope in patients with ChC 7 , and no study has demonstrated the determinants of the VE/VCO 2 slope in this population. Thus, the present study aimed to verify the clinical, echocardiographic, and functional determinants of the VE/VCO 2 slope in patients with ChC. This cross-sectional study verified the determinants of VE/VCO 2 slope in patients with ChC recruited from an outpatient