Impaired coronary flow reserve in patients with indeterminate form of Chagas' disease.

BACKGROUND: Previous studies suggest that microvascular abnormalities may contribute to the pathogenesis of Chagas' heart disease. Coronary flow reserve (CFR) expressed by the maximum achievable flow relative to baseline flow in the coronary microcirculation, may be useful in identifying patients who may be developing cardiac manifestations of the disease. This study aims to assess the CFR in patients with indeterminate form of Chagas' disease, and also to identify the determinants of CFR. METHODS: Sixty-four asymptomatic patients (37% male; age 49.9 ± 11.5 years) with normal cardiovascular exams classified as in indeterminate form of Chagas' disease underwent transthoracic dipyridamole (0.84 mg/kg in 6 min) stress echocardiography, and were compared with a control group of healthy patients. Coronary flow reserve was assessed on left anterior descending artery using pulsed Doppler as the ratio of maximal peak vasodilation (dipyridamole) to rest diastolic flow velocity. A treadmill exercise test was performed to rule out ischemia. RESULTS: All patients had good functional capacity assessed by exercise testing with peak oxygen consumption (VO2 ) of 28 ± 11 mL/kg per minute, similar to the controls. There were no differences in the echocardiographic parameters of diastolic and systolic left ventricular function and right ventricular function between the patients and controls. Coronary flow reserve was significantly lower in Chagas' disease patients than those in healthy individuals (1.9 ± 0.4 vs. 2.6 ± 0.5; P < 0.001). Several factors were correlated with the CFR, including age, ejection fraction, left ventricular diastolic function, heart rate recovery, and the presence of Chagas' disease. In a multivariate analysis, age and positive serology for Chagas' disease were independent factors associated with the CFR. CONCLUSIONS: Coronary flow reserve was impaired in Chagas' disease patients in the indeterminate form compared with healthy individuals with similar clinical features. Among all variables tested, age and positive serology for Chagas' disease were independent factors associated with the CFR.

Infrapopliteal mycotic aneurysm caused by endocarditis--case report and literature review.

Infrapopliteal mycotic aneurysm resulting from endocarditis is rare, with few reported cases in the literature. We describe a case of ruptured mycotic aneurysm involving the infrapopliteal artery in a patient with aortic and mitral endocarditis. Duplex scanning revealed an oval-shaped mass at the infrapopliteal segment, consistent with sacular aneurysm. The aneurysm showed signs of rupture and pseudoaneurysm formation, which was confirmed by angio-MRI and arteriography. The patient was treated by endovascular procedure and remained asymptomatic at the 6-month follow-up.

Mechanical Dispersion Assessed by Strain Echocardiography Is Associated with Malignant Arrhythmias in Chagas Cardiomyopathy.

BACKGROUND: Sudden death is one of the characteristics of Chagas disease (ChD). With the development of strategies for the prevention of malignant arrhythmias, especially with implantable cardioverter-defibrillators (ICDs), there is interest in developing strategies to predict sudden cardiac death. The aim of this study was to test the hypothesis that global longitudinal strain (GLS) and mechanical dispersion (MD) may be associated with malignant ventricular arrhythmias in patients with ChD. METHODS: A cross-sectional study was conducted including 62 patients with ChD who were separated into two groups according to ICD implantation status. Group 0 consisted of 34 patients with ChD without ICDs, and group 1 comprised 28 patients with ICDs. Complete echocardiographic studies, including GLS and MD measurements, were performed in all patients. RESULTS: Chamber dimensions, ejection fraction, and diastolic function showed no significant differences between patients with and those without ICDs. GLS was reduced in patients with ChD with ICDs compared with those without (P = .02). By receiver operating characteristic curve analyses, GLS identified patients with ChD with ICDs with sensitivity of 67% and specificity of 69%. MD was more pronounced in patients with ChD with ICDs compared with those without (P < .001), with a C statistic of 0.83 (95% CI, 0.71-0.91). MD > 57 msec detected ICD presence with sensitivity of 79% and specificity of 71% and was superior to GLS and ejection fraction (P < .05). In multivariate analysis, New York Heart Association functional class (odds ratio, 3.02; 95% CI, 1.09-8.39; P = .03), MD (odds ratio, 1.11; 95% CI, 1.04-1.19; P = .001), and GLS (odds ratio, 0.72; 95% CI, 0.54-0.96; P = .026) were significant and independently associated with malignant arrhythmic events. CONCLUSIONS: GLS and MD may add important information in the risk stratification of patients with ChD. The use of MD by strain echocardiography could be an attractive tool in the decision making for ICD placement as primary prevention for sudden cardiac death in patients with ChD.

Heart rate turbulence in Chagas disease.

Heart rate turbulence (HRT) quantifies the biphasic response of the sinus node to ventricular premature complexes (VPCs) and is a powerful electrocardiogram related risk predictor. VPCs are frequent in Chagas disease, a potentially lethal illness, and can hamper the analysis by conventional methods of autonomic heart control. The aim of the study was to examine HRT in patients with Chagas disease. Chagas disease patients and healthy controls (group 0, n = 11) without other diseases were submitted to a standardized protocol, including electrocardiogram, echocardiography, and 24-hour Holter monitoring. Chagas disease patients were divided according to their left ventricular systolic function: normal (group 1, n = 103) and reduced ejection fraction (group 2, n = 23). Two HRT indices, turbulence onset (TO) and turbulence slope (TS), were calculated and compared among groups after adjustment for covariates like the prevalence of VPCs and the mean heart rate. Chagas disease patients had significantly altered TO (group 1: -0.0186, group 2: -0.0126) and TS (group 1: 10.844, group 2: 7.870) values in comparison with controls (TO -0.0256, TS 19.829); P < 0.001 for both comparisons. In conclusion, HRT data may be useful in the electrocardiographic analysis of autonomic heart control in Chagas disease. Its prognostic value remains to be determined.

Importância do exame clínico no diagnóstico de sopro inocente em adolescentes / The importance of clinical examination for the diagnosis of innocent hearth murmur in adolescents

Objetivo - Determinar a prevalência de sopro inocente em adolescentes, avaliando a importância do exame clínico no diagnóstico do mesmo, tendo como "padräo ouro" o estudo Doppler-ecocardiográfico. Método - Este estudo, realizado no período de março a dezembro de 1992, abordou alunos de primeiro e segundo graus, com idade entre 10 e 20 anos, oriundos de famílias de clases média e média-baixa. Os 536 participantes foram selecionados a partir da randomizaçäo dos 1400 alunos matriculados. Os alunos sorteados foram entrevistados e examinados por um dos pesquisadores, sendo que 27 crianças com sopro cardíaco foram submetidas a estudo Doppler-ecocardiográfico. Resultados - Dos 536 alunos examinados, 171 (32 por cento) apresentavam algum tipo de sopro cardíaco, sendo que 160 (29,9 por cento) foram considerados como portadores de sopro inocente, e 11 (21 por cento) de "sopro näo inocente". Dentre os 27 adolescentes com sopro que foram submetidos a estudo Doppler-ecocardiográfico, em 20 esse exame confirmou o diagnóstico de sopro inocente, näo evidenciando qualquer anormalidade ou sendo vizibilizados achados considerados fisiológicos. Das sete crianças com diagnóstico clínico de "sopro näo inocente", o estudo Doppler-ecocardiográfico demonstrou lesäo cardíaca em dois (pequena comunicaçäo interventricular e valvopatia reumática:dupla lesäo mitral e insuficiência aórtica) e dados anátomo-funcionais normais em cinco. Conclusäo - Diante dos resultados obtidos, a prevalência global de sopro inocente em adolescente foi calculada em 29,9 por cento. Sugere-se o exame clínico bem feito, realizado por médicos treinados em semiologia cardiovascular, é capaz de definir o diagnóstico de sopro inocente na maioria dos casos (sensibilidade de 100 por cento e especificidade de 80 por cento).