ABC | Volume 114, Nº4, April 2020

Original Article Absence of Nocturnal Fall in Blood Pressure Detected by Ambulatory Blood Pressure Monitoring in Acute Chagas Disease Patients with Oral Infection Dilma do S. M. de Souza, 1 Céres Larissa Barbosa de Oliveira, 1 Brenda Gonçalves Maciel, 1 Maria Tereza Figueiredo, 1 Henrique Tria Bianco, 2 Francisco A. H. Fonseca, 2 M aria Cristina Izar, 2 R ui M. S. Póvoa 2 Universidade Federal do Pará, 1 Belém, PA - Brazil Universidade Federal de São Paulo – Escola Paulista de Medicina, 2 São Paulo, SP - Brazil Mailing Address: Henrique Tria Bianco • Universidade Federal de São Paulo – Escola Paulista de Medicina - Rua Loefgren, 1350 Postal Code 04040-001, São Paulo, SP – Brazil E-mail: henriquetria@uol.com.br Manuscript received February 26, 2019, revised mansucript June 09, 2020, accepted June 23, 2020 DOI: https://doi.org/10.36660/abc.20190143 Abstract Background: The involvement of the autonomic nervous system is one of the mechanisms proposed to explain the progression of myocardial lesion in Chagas disease. Evidences have shown changes in sympathetic and parasympathetic nervous system since the acute phase of the disease, and studies to clarify the pathophysiological and prognostic value of these changes are needed. Objetives: To assess blood pressure profile by ambulatory blood pressure monitoring (ABPM) in normotensive patients with acute Chagas disease (ACD) without apparent cardiac damage, and the influence of the infection on nocturnal blood pressure fall. Methods: ABPM was performed with 54 patients with ACD and a control group composed of 54 age- and sex-matched normotensive individuals. The alpha level of significance (type I error rate) was set at 5%. Results: In the total of 54 patients, 74.0% did not show nocturnal fall in systolic blood pressure, 53.7% did not show nocturnal fall in diastolic blood pressure, and lack of both nocturnal fall in SBP and DBP was observed in 51.8% (*p<0.05). In 12.9% of patients, there was an increase in SBP and in 18.5% increase in DBP (p<0.05). Conclusions: In patients with acute Chagas disease, a significant absence of the physiological fall in both systolic and diastolic blood pressure was observed during sleep, and some of the patients showed nocturnal increase in these parameters. These findings suggest autonomic changes in the acute phase of Chagas disease. (Arq Bras Cardiol. 2020; 114(4):711-715) Keywords: Chagas Disease/physiopathology; Blood Pressure/physiology; Autonomic Nervous System/physiology; Blood Pressure Monitoring, Ambulatory/methods; Hypertension. Introduction Chagas disease is a zoonosis caused by the flagellate protozoan Trypanosoma cruzi ( T. cruzi ) that feeds primarily on blood. The disease is endemic in 21 countries in Latin America, with an important social impact due to its high morbidity and mortality. According to theWorld Health Organization (WHO), it is estimated that 6-7 million people are infected, most of them in Latin America. 1 The classical form of transmission – vector transmission – has been decreasing in endemic areas in Latin America thanks to infection control initiatives. However, intense deforestation in the Amazon region, in addition to migration of people, has changed the epidemiological scenario, with an expressive increase in oral transmission. 2 The most common clinical presentation in the acute phase of the orally transmitted disease includes prolonged fever syndrome, usually associated with familial microepidemics, and several unspecific symptoms characteristic of vector transmission of Chagas disease, but with higher morbidity and mortality. 3-5 In the chronic form of the disease, important changes in the autonomic system are observed, with increased sympathetic activity and decreased parasympathetic activity. However, autonomic changes in the acute phase of the disease are not known so far. Many patients have altered blood pressure (BP) and abnormal ambulatory blood pressure monitoring (ABPM) measures, mainly related to nocturnal BP fall. In non- chagasic patients, such event has been regarded as a sign of dysautonomia and possible predictor of cardiovascular risk. 6 In light of the physiological decline in nocturnal BP, an ABPM in acute Chagas disease (ACD) is advisable, aiming at a better understanding of BP behavior, especially during sleep. Therefore, the aim of the present study was to assess BP behavior in patients with ACD using ABPM. 711