BACKGROUND A positive Trypanosoma cruzi polymerase chain reaction (PCR) is associated with a worse prognosis in patients with chronic Chagas disease (CD). OBJECTIVES To study the association of clinical, electrocardiographic, and echocardiographic characteristics and biomarker blood levels with positive T. cruzi PCR in chronic CD. METHODS This is a single-centre observational cross-sectional study. Positive T. cruzi PCR association with clinical, electrocardiographic, and echocardiographic characteristics, and biomarker blood levels were studied by logistic regression analysis. p values < 0.05 were considered significant. FINDINGS Among 333 patients with chronic CD (56.4% men; 62 ± 10 years), T. cruzi PCR was positive in 41.1%. Stepwise multivariate logistic regression showed an independent association between positive T. cruzi PCR and diabetes mellitus {odds ratio (OR) 0.53 [95% confidence interval (CI) 0.30-0.93]; p = 0.03}, right bundle branch block [OR 1.78 (95% CI 1.09-2.89); p = 0.02], and history of trypanocidal treatment [OR 0.13 (95% CI 0.04-0.38); p = 0.0002]. Among patients with a history of trypanocidal treatment (n = 39), only four (10%) patients had a positive T. cruzi PCR. MAIN CONCLUSIONS Among several studied parameters, only diabetes mellitus, right bundle branch block, and history of trypanocidal treatment showed an independent association with positive T. cruzi PCR. History of trypanocidal treatment was a strong protective factor against a positive T. cruzi PCR.

Abstract Background The importance of regional sympathetic denervation in the pathophysiology and prognosis of Chagas disease has been recognized. Objective To conduct a review of studies that have assessed dysautonomia in chronic Chagas heart disease. Methods The search was performed on the Medline, Pubmed, Lilacs and SciELO databases. The inclusion criteria were: original articles published in full; studies on individuals with Chagas disease, that used diagnostic methods for chagasic cardiomyopathy, and had clear inclusion and exclusion criteria. Duplicate studies, studies including children (0 to 10 years old), studies involving animals, in vitro experiments, case reports, editorials, theses, and dissertations were excluded. Results A total of 281 articles were retrieved, and 10 met the inclusion criteria and were analyzed. There was great heterogeneity as to the technique for assessing dysautonomia, groups of patients studied and classification of Chagas disease. The methods used for studying the autonomic system was immunohistochemistry (n=1), Valsalva and tilt-test (n=1), scintigraphy (n=6) and Holter monitoring (n=2). The results indicated dysautonomia in the indeterminate, digestive and cardiac forms of Chagas disease, and sympathetic denervation in the indeterminate and cardiac forms of the disease. There was agreement between areas of denervation, hypoperfusion and fibrosis, but areas of denervation were larger than those of hypoperfusion. The frequency of denervation and its extension increased from the indeterminate to the cardiac form. There was an association between extension of denervation and previous history of malignant ventricular arrhythmia. Conclusions The evidence presented in this review supports that an early diagnosis of autonomic denervation in chronic Chagas' disease allows the identification of patients with an increased risk of sudden death. Int J Cardiovasc Sci. 2020; [online].ahead print, PP.0-0