Combined parasitological and molecular-based diagnostic tools improve the detection of Trypanosoma cruzi in single peripheral blood samples from patients with Chagas disease

Abstract INTRODUCTION In order to detect Trypanosoma cruzi and determine the genetic profiles of the parasite during the chronic phase of Chagas disease (ChD), parasitological and molecular diagnostic methods were used to assess the blood of 91 patients without specific prior treatment. METHODS Blood samples were collected from 68 patients with cardiac ChD and 23 patients with an indeterminate form of ChD, followed by evaluation using blood culture and polymerase chain reaction. T . cruzi isolates were genotyped using three different genetic markers. RESULTS: Blood culture was positive in 54.9% of all patients, among which 60.3% had the cardiac form of ChD, and 39.1% the indeterminate form of ChD. There were no significant differences in blood culture positivity among patients with cardiac and indeterminate forms. Additionally, patient age and clinical forms did not influence blood culture results. Polymerase chain reaction (PCR) was positive in 98.9% of patients, although comparisons between blood culture and PCR results showed that the two techniques did not agree. Forty-two T . cruzi stocks were isolated, and TcII was detected in 95.2% of isolates. Additionally, one isolate corresponded to TcIII or TcIV, and another corresponded to TcV or TcVI. CONCLUSIONS Blood culture and PCR were both effective for identifying T. cruzi using a single blood sample, and their association did not improve parasite detection. However, we were not able to establish an association between the clinical form of ChD and the genetic profile of the parasite.

Exercise-induced ventricular arrhythmias and vagal dysfunction in Chagas disease patients with no apparent cardiac involvement

INTRODUCTION : Exercise-induced ventricular arrhythmia (EIVA) and autonomic imbalance are considered as early markers of heart disease in Chagas disease (ChD) patients. The objective of the present study was to verify the differences in the occurrence of EIVA and autonomic maneuver indexes between healthy individuals and ChD patients with no apparent cardiac involvement. METHODS : A total of 75 ChD patients with no apparent cardiac involvement, aged 44.7 (8.5) years, and 38 healthy individuals, aged 44.0 (9.2) years, were evaluated using echocardiography, symptom-limited treadmill exercise testing and autonomic function tests. RESULTS : The occurrence of EIVA was higher in the chagasic group (48%) than in the control group (23.7%) during both the effort and the recovery phases. Frequent ventricular contractions occurred only in the patient group. Additionally, the respiratory sinus arrhythmia index was significantly lower in the chagasic individuals compared with the control group. CONCLUSIONS : ChD patients with no apparent cardiac involvement had a higher frequency of EIVA as well as more vagal dysfunction by respiratory sinus arrhythmia. These results suggest that even when asymptomatic, ChD patients possess important arrhythmogenic substrates and subclinical disease. .

Health-related quality of life in patients with Chagas disease: a review of the evidence

Chagas disease (ChD), a neglected tropical disease caused by infection with the parasite Trypanosoma cruzi (T. cruzi), remains a serious public health issue in Latin America and is an emerging disease in several non-endemic countries, where knowledge of the condition and experience with its clinical management are limited. Regionally, the disease is the major cause of disability secondary to tropical diseases in young adults. Health-related quality of life (HRQoL) impairment is common in patients with ChD, especially in those with Chagas dilated cardiomyopathy, the most severe manifestation of the disease, which frequently leads to heart failure. The aim of this review was to conduct a literature search for studies that have evaluated the determining factors of HRQoL in ChD patients. We included cross-sectional, case-control, cohort, and experimental studies, as well as clinical trials that evaluated the HRQoL in ChD patients aged 18 to 60 years and are presenting an explicit description of statistical analysis. Using a combination of keywords based on Descriptors in Health Sciences (DeCS) and Medical Subject Headings (MeSH) for searches in PubMed and the Scientific Electronic Library Online (SciELO), 148 studies were found. After exclusions, 12 studies were selected for analysis. Three main findings were extracted from these studies: 1) cardiac involvement is associated with a worse HRQoL in ChD patients; 2) HRQoL is associated with the patients' functional capacity; and 3) simple and inexpensive therapeutic measures are effective for improving HRQoL in ChD patients. Hence, ChD patients' functional capacity, the effectiveness of non-surgical conservative treatment, and cardiac involvement are important determining factors for the HRQoL in ChD patients.

Relação entre a fração de ejeção do ventrículo esquerdo e razão e/e' com a capacidade funcional na cardiopatia chagásica / Relationship between left ventricular ejection fraction and e /e' ratiowith functional capacity in chagas heart disease

Introdução: disfunção ventricular e capacidade funcional são importantes marcadores de morbimortalidade na cardiopatia chagásica (CCh). Objetivos: verificar a associação entre a capacidade funcional e funções sistólica e diastólica do ventrículo esquerdo na CCh. Metodologia: foram submetidos 35 pacientes com CCh (47,11±8,15 anos) a avaliação clínica, ecocardiograma e teste de esforço cardiopulmonar (TECP), sendo classificados em dois grupos: dilatado (com cardiomiopatia dilatada) e não dilatado (função sistólica preservada). Foram consideradas as variáveis fração de ejeção do ventrículo esquerdo (FEVE), razão E/e' e o pico do consumo de oxigênio (VO2pico). Na análise estatística foram realizados os testes de Pearson ou Spearman e a análise de regressão linear múltipla avaliou o efeito da FEVE e E/e' no VO2pico. Resultados: na amostra total houve correlação significativa entre o VO2pico e a FEVE (r=0,536, p=0,001) e correlação negativa e significativa entre o VO2pico e razão E/e' (r=-0,399; p=0,022). No grupo dilatado (n=16), correlação significativa foi observada entre o VO2pico com a FEVE (r=0,611, p=0,016) e a razão E/e' (r=-0,601, p=0,018). A análise multivariada das variáveis identificou a FEVE e a razão E/e' como fortes preditores do VO2pico (r=0,850; r2 =0,723).Não houve correlação significativa entre o VO2pico e a FEVE (r=0,393, p=0,107) e a razão E/e' (r=0,102, p=0,687) no grupo não dilatado (n=19). Conclusão: a capacidade funcional avaliada pelo VO2pico relaciona-se à função sistólica e diastólica em pacientes com cardiomiopatia dilatada chagásica.

Background: Left ventricular dysfunction and functional capacity (FC) are important markers of morbidity and mortality in Chagas heart disease (CHD), however, the relationship between these clinical parameters remains controversial. Objective: To verify the association between FC and systolic and diastolic functions of the left ventricle in CHD patients. Methods: Thirty-five CHD patients (47.11±8.15 years) underwent clinical evaluation, echocardiography and Cardiopulmonary Exercise Testing (CPET) and were classified into two groups: dilated group (dilated cardiomyopathy) and non-dilated group (preserved systolic function). The left ventricular ejection fraction (LVEF), E/e' ratio and peak oxygenuptake (VO2peak)were considered. Statistical analysis was carried outwith Pearson or Spearman correlation tests and backward multivariate linear regression analysis was performed to assess the effect of LVEF and E/e' ratio on VO2peak. Results: In the overall study population, there was a significant correlation between VO2peak and LVEF (r=0.536; p=0.001) and a significant negative correlation between VO2peak and E/e' ratio (r=-0.399;p=0.022). In the dilated group (n=16), a significant correlation was also observed between VO2peak and both LVEF(r=0.611; p=0.016) and E/e' ratio (r=-0.601; p=0.018). The multivariate analysis of these variables identified the LVEF and E/e' ratio as strong predictors of VO2peak (r=0.850; r2=0.723). In contrast, in the non-dilated group (n=19), there was no significant correlation between VO- 2peak and LVEF (r=0.393; p=0.107) and E/e' ratio (r=0.102; p=0.687). Conclusion: Functional capacity assessed by VO2peak was related to systolic and diastolic function in CHD patients with dilated cardiomyopathy.