RESUMO
Chagas disease, caused by the triatominae Trypanosoma cruzi, is one of the leading causes of heart malfunctioning in Latin America. The cardiac phenotype is observed in 20-30% of infected people 10-40 years after their primary infection. The cardiac complications during Chagas disease range from cardiac arrhythmias to heart failure, with important involvement of the right ventricle. Interestingly, no studies have evaluated the electrical properties of right ventricle myocytes during Chagas disease and correlated them to parasite persistence. Taking advantage of a murine model of Chagas disease, we studied the histological and electrical properties of right ventricle in acute (30 days postinfection [dpi]) and chronic phases (90 dpi) of infected mice with the Colombian strain of T. cruzi and their correlation to parasite persistence. We observed an increase in collagen deposition and inflammatory infiltrate at both 30 and 90 dpi. Furthermore, using reverse transcriptase polymerase chain reaction, we detected parasites at 90 dpi in right and left ventricles. In addition, we observed action potential prolongation and reduced transient outward K(+) current and L-type Ca(2+) current at 30 and 90 dpi. Taking together, our results demonstrate that T. cruzi infection leads to important modifications in electrical properties associated with inflammatory infiltrate and parasite persistence in mice right ventricle, suggesting a causal role between inflammation, parasite persistence, and altered cardiomyocyte function in Chagas disease. Thus, arrhythmias observed in Chagas disease may be partially related to altered electrical function in right ventricle.
Assuntos
Cardiomiopatia Chagásica/patologia , Cardiomiopatia Chagásica/parasitologia , Miócitos Cardíacos/fisiologia , Miócitos Cardíacos/parasitologia , Trypanosoma cruzi , Animais , Ventrículos do Coração/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Disfunção Ventricular Direita/parasitologia , Disfunção Ventricular Direita/patologiaRESUMO
This study was performed to assess the safety and feasibility of the implantation of ventricular assist devices (VADs) as a bridge to heart transplantation in patients with advanced biventricular failure due to Chagas' disease. Six patients were submitted to paracorporeal left VAD implantation, while right ventricular dysfunction was managed clinically. The mean time of circulatory support was 27 days. Two patients were bridged to heart transplantation successfully, while the other four patients died under assistance with complications that correlated with the final situation of multiple organ failure. Nevertheless, persistent right ventricular dysfunction was observed only in one patient who survived more than 15 days, despite the general significant preoperative compromise of the right ventricle. This paradoxical observation indicates that left VAD implantation may be regarded as a valuable treatment option for patients with Chagas' disease cardiomyopathy who evolve with decompensated heart failure or cardiogenic shock.
Assuntos
Cardiomiopatia Chagásica/cirurgia , Insuficiência Cardíaca/terapia , Transplante de Coração , Coração Auxiliar , Expectativa de Vida , Disfunção Ventricular Esquerda/cirurgia , Adulto , Pressão Sanguínea/fisiologia , Transplante de Medula Óssea , Débito Cardíaco/fisiologia , Cardiomiopatia Chagásica/parasitologia , Cardiomiopatia Chagásica/fisiopatologia , Feminino , Insuficiência Cardíaca/parasitologia , Insuficiência Cardíaca/fisiopatologia , Testes de Função Cardíaca , Coração Auxiliar/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Disfunção Ventricular Esquerda/parasitologia , Disfunção Ventricular Esquerda/fisiopatologia , Disfunção Ventricular Direita/tratamento farmacológico , Disfunção Ventricular Direita/parasitologia , Disfunção Ventricular Direita/fisiopatologiaRESUMO
Chagas' disease caused by infection with Trypanosoma cruzi leads to a myocardiopathy that evolves from the acute to the chronic phase. Magnetic resonance imaging (MRI) is an important tool for monitoring cardiac morphology and function both in humans and in animals. In the present work, we present a brief review of MRI applications for the study of ventricular hypertrophy and dilatation of the right ventricle in murine models of Chagas' disease. Studies using MRI demonstrate an increase in right ventricular chamber dimension during both phases of infection, indicating that increase of the right ventricle is a marker for experimental chagasic myocardiopathy. Based on previous studies using MRI in these models we propose that this technique is an excellent approach for monitoring heart functionality from the acute through the chronic phase of infection in different parasite-host pairs and for monitoring the efficacy of cardioprotective or immune-therapeutic agents.