Reduced Cardiac Index Reserve and Hypovolemia in Severe Falciparum Malaria.

BACKGROUND: Impaired microvascular perfusion is central to the development of coma and lactic acidosis in severe falciparum malaria. Refractory hypotension is rare on admission but develops frequently in fatal cases. We assessed cardiac function and volume status in severe falciparum malaria and its prognostic significance. METHODS: Patients with severe (N = 101) or acute uncomplicated falciparum malaria (N = 83) were recruited from 2 hospitals in India and Bangladesh, and healthy participants (N = 44) underwent echocardiography. RESULTS: Patients with severe malaria had 38% shorter left ventricular (LV) filling times and 25% shorter LV ejection times than healthy participants because of tachycardia; however, stroke volume, LV internal diameter in diastole (LVIDd), and LV internal diameter in systole (LVIDs) indices were similar. A low endocardial fraction shortening (eFS) was present in 17% (9 of 52) of severe malaria patients. Adjusting for preload and afterload, eFS was similar in health and severe malaria. Fatal cases had smaller baseline LVIDd and LVIDs indices, more collapsible inferior vena cavae (IVC), and higher heart rates than survivors. The LVIDs and IVC collapsibility were independent predictors for mortality, together with base excess and Glasgow Coma Scale. CONCLUSIONS: Patients with severe malaria have rapid ejection of a normal stroke volume. Fatal cases had features of relative hypovolemia and reduced cardiac index reserve.

Left ventricular hemodynamic forces as a marker of mechanical dyssynchrony in heart failure patients with left bundle branch block.

Left bundle branch block (LBBB) causes left ventricular (LV) dyssynchrony which is often associated with heart failure. A significant proportion of heart failure patients do not demonstrate clinical improvement despite cardiac resynchronization therapy (CRT). How LBBB-related effects on LV diastolic function may contribute to those therapeutic failures has not been clarified. We hypothesized that LV hemodynamic forces calculated from 4D flow MRI could serve as a marker of diastolic mechanical dyssynchrony in LBBB hearts. MRI data were acquired in heart failure patients with LBBB or matched patients without LBBB. LV pressure gradients were calculated from the Navier-Stokes equations. Integration of the pressure gradients over the LV volume rendered the hemodynamic forces. The findings demonstrate that the LV filling forces are more orthogonal to the main LV flow direction in heart failure patients with LBBB compared to those without LBBB during early but not late diastole. The greater the conduction abnormality the greater the discordance of LV filling force with the predominant LV flow direction (r2 = 0.49). Such unique flow-specific measures of mechanical dyssynchrony may serve as an additional tool for considering the risks imposed by conduction abnormalities in heart failure patients and prove to be useful in predicting response to CRT.

Genetic Polymorphisms of IL17 and Chagas Disease in the South and Southeast of Brazil.

The aim of this study was to investigate possible associations between genetic polymorphisms of IL17A G197A (rs2275913) and IL17F T7488C (rs763780) with Chagas Disease (CD) and/or the severity of left ventricular systolic dysfunction (LVSD) in patients with chronic Chagas cardiomyopathy (CCC). The study with 260 patients and 150 controls was conducted in the South and Southeast regions of Brazil. The genotyping was performed by PCR-RFLP. The A allele and A/A genotype of IL17A were significantly increased in patients and their subgroups (patients with CCC; patients with CCC and LVSD; and patients with CCC and severe LVSD) when compared to the control group. The analysis according to the gender showed that the A/A genotype of IL17A was more frequent in female with LVSD and mild to moderate LVSD and also in male patients with LVSD. The frequency of IL17F T/C genotype was higher in male patients with CCC and severe LVSD and in female with mild to moderate LVSD. The results suggest the possible involvement of the polymorphisms of IL17A and IL17F in the susceptibility to chronic Chagas disease and in development and progression of cardiomyopathy.

Histopathological Correlates of Global and Segmental Left Ventricular Systolic Dysfunction in Experimental Chronic Chagas Cardiomyopathy.

BACKGROUND: Chronic Chagas cardiomyopathy in humans is characterized by segmental left ventricular wall motion abnormalities (WMA), mainly in the early stages of disease. This study aimed at investigating the detection of WMA and its correlation with the underlying histopathological changes in a chronic Chagas cardiomyopathy model in hamsters. METHODS AND RESULTS: Female Syrian hamsters (n=34) infected with 3.5×10(4) or 10(5) blood trypomastigote Trypanosoma cruzi (Y strain) forms and an uninfected control group (n=7) were investigated. After 6 or 10 months after the infection, the animals were submitted to in vivo evaluation of global and segmental left ventricular systolic function by echocardiography, followed by euthanasia and histological analysis for quantitative assessment of fibrosis and inflammation with tissue sampling in locations coinciding with the left ventricular wall segmentation employed at the in vivo echocardiographic evaluation. Ten of the 34 infected animals (29%) showed reduced left ventricular ejection fraction (<73%). Left ventricular ejection fraction was more negatively correlated with the intensity of inflammation (r=-0.63; P<0.0001) than with the extent of fibrosis (r=-0.36; P=0.036). Among the 24 animals with preserved left ventricular ejection fraction (82.9±5.5%), 8 (33%) showed segmental WMA predominating in the apical, inferior, and posterolateral segments. The segments exhibiting WMA, in comparison to those with normal wall motion, showed a greater extent of fibrosis (9.3±5.7% and 7±6.3%, P<0.0001) and an even greater intensity of inflammation (218.0±111.6 and 124.5±84.8 nuclei/mm², P<0.0001). CONCLUSIONS: Isolated WMA with preserved global systolic left ventricular function is frequently found in Syrian hamsters with experimental chronic Chagas cardiomyopathy whose underlying histopathological features are mainly inflammatory.

Myocardial tissue characterization in Chagas' heart disease by cardiovascular magnetic resonance.

BACKGROUND: Chagas' heart disease is an important public health problem in South America. Several aspects of the pathogenesis are not fully understood, especially in its subclinical phases. On pathology Chagas' heart disease is characterized by chronic myocardial inflammation and extensive myocardial fibrosis. The latter has also been demonstrated by late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR). In three clinical phases of this disease, we sought to investigate the presence of LGE, myocardial increase in signal intensity in T2-weighted images (T2W) and in T1-weighted myocardial early gadolinium enhancement (MEGE), previously described CMR surrogates for myocardial fibrosis, myocardial edema and hyperemia, respectively. METHODS: Fifty-four patients were analyzed. Sixteen patients with the indeterminate phase (IND), seventeen patients with the cardiac phase with no left ventricular systolic dysfunction (CPND), and twenty-one patients with the cardiac phase with left ventricular systolic dysfunction (CPD). All patients underwent 1.5 T CMR scan including LGE, T2W and MEGE image sequences to evaluate myocardial abnormalities. RESULTS: Late gadolinium enhancement was present in 72.2 % of all patients, in 12.5 % of IND, 94.1 % of the CPND and 100 % of the CPD patients (p < 0.0001). Myocardial increase in signal intensity in T2-weighted images (T2W) was present in 77.8 % of all patients, in 31.3 % of the IND, 94.1 % of the CPND and 100 % of the CPD patients (p < 0.0001). T1-weighted myocardial early gadolinium enhancement (MEGE) was present in 73.8 % of all patients, in 25.0 % of the IND, 92.3 % of the CPND and 94.1 % of the CPD (p < 0.0001). A good correlation between LGE and T2W was observed (r = 0.72, and p < 0.001). CONCLUSIONS: Increase in T2-weighted (T2W) myocardial signal intensity and T1-weighted myocardial early gadolinium enhancement (MEGE) can be detected by CMR in patients throughout all phases of Chagas' heart disease, including its subclinical presentation (IND). Moreover, those findings were parallel to myocardial fibrosis (LGE) in extent and location and also correlated with the degree of Chagas' heart disease clinical severity. These findings contribute to further the knowledge on pathophysiology of Chagas' heart disease, and might have therapeutic and prognostic usefulness in the future.

Strain and Strain Rate Measured on Echocardiogram 1-3 Weeks after Starting Treatment Is Worse in Acute Dilated Cardiomyopathy Pediatric Patients with Poor Outcomes at One Year.

BACKGROUND: Predicting later outcome around time of diagnosis of acute dilated cardiomyopathy (DCM) is difficult. We hypothesized that strain and strain rate on initial and follow-up echoes were worse in patients with acute DCM from all causes with poor one-year outcomes. METHODS: This was a retrospective study including all patients with DCM aged 0-18 years with left ventricle dilation, low ejection fraction, or low fractional shortening on initial echo. Longitudinal and circumferential strain and systolic and diastolic strain rate were measured on echo at presentation, 1-3 weeks after presentation, and at 1 year. Patients were separated into "Stable" (survivors) and "Progressive" (referred for transplant or died) outcome groups, and results were analyzed to determine whether strain or strain rate at each echo was worse in the "Stable" group compared with the "Progressive" group. RESULTS: The patient population included patients with DCM from idiopathic causes, myocarditis, iron deficiency anemia, lupus, chemotherapy, and LV noncompaction. Longitudinal and circumferential strain and systolic strain rate were significantly better in the "Stable" (n = 7) compared with the "Progressive" (n = 8) outcome group on 1- to 3-week echo. Longitudinal strain more negative than -10% had 87% specificity and 100% sensitivity for predicting "stable" outcome (AUC 0.98), while circumferential strain more negative than -8% had 60% specificity and 100% sensitivity (AUC 0.83). CONCLUSIONS: Longitudinal and circumferential strain and systolic strain rate measured 1-3 weeks after starting therapy are worse in acute dilated cardiomyopathy patients with poor one-year outcomes. Further studies with less heterogeneity and more study subjects are needed.

Device therapy in Chagas disease heart failure.

Chagas disease is the principal cause of chronic heart failure in areas where the disease is endemic. The medical treatment is the same recommended for non-Chagas disease patients. There is no evidence-based medicine support for device therapy in Chagas disease heart failure. Cardiac resynchronization therapy is recommended for Chagas disease heart failure patients with intraventricular conduction disturbances, mainly for those with left bundle branch block, and in advanced congestive heart failure refractory to targeted medical treatment, although this therapy is still polemic in Chagas disease heart failure. Implantable cardioverter-defibrillator (ICD) therapy is indicated to Chagas disease patients with left ventricular ejection fraction <30% for primary prevention of sudden cardiac death. ICD therapy is offered to patients for secondary prevention of sudden cardiac death. Patients with moderate left ventricular dysfunction and inducible arrhythmia at electrophysiological testing should receive ICD therapy.

Cardiac function in Ghanaian children with severe malaria.

PURPOSE: The aim was to assess whether impaired cardiac function contributes to symptoms of severe malaria in general or to metabolic acidosis in particular in children living in endemic regions. METHODS: In a prospective observational investigation, 183 children with severe malaria were investigated for hemodynamic status and cardiac function upon admission (day 0) and after recovery (day 42). Cardiac function parameters were assessed by cardiac ultrasonography. Blood gas analyses and cardiac enzymes were measured at hospitalization and follow-up. Differences in subgroups with and without metabolic acidosis as well as other severe malaria-defining symptoms and conditions were assessed. RESULTS: Cardiac index (CI) was significantly increased on day 0 compared to day 42 (5.8 ml/m(2), SD ± 1.8 ml/m(2), versus 4.7 ml/m(2), SD ± 1.4 ml/m(2); P < 0.001). CI correlated negatively with hemoglobin levels but not with parameters indicating impaired tissue perfusion or metabolic acidosis. Parasite levels had a significant influence on metabolic acidosis but not on CI. Alterations related to cardiac function, hemoglobin levels and metabolic acidosis were most prominent in children younger than 2 years. CONCLUSION: Increased CI reflecting high output status is associated with low hemoglobin levels while metabolic acidosis is linked to parasite levels.

Stroke in asymptomatic Trypanosoma cruzi-infected patients.

BACKGROUND: The knowledge about the natural history of stroke in Chagas disease is incomplete. METHODS: Vascular risk factors and stroke subtypes of asymptomatic Trypanosoma cruzi-infected patients with no clinical evidence of heart failure were assessed. They were compared with chronic chagasic cardiomyopathy patients who suffered a stroke and with a control group of 60 T. cruzi-noninfected stroke patients. Eighty-six consecutive chagasic stroke patients (mean age: 57.4 years; 64% females) were studied. RESULTS: 38.4% of chagasic stroke patients had asymptomatic T. cruzi infection. Smoking was more frequent in asymptomatic chagasic stroke patients (21.2 vs. 5.7%; p = 0.04). Prevalence of hypertension, diabetes and prior stroke was similar in both groups. Small-vessel infarction (15.6 vs. 3.8%) and large-vessel atherosclerosis (9.4 vs. 3.8%) were significantly more frequent in asymptomatic than in symptomatic T. cruzi-infected stroke patients (p = 0.001). Nevertheless, their frequency was even higher in T. cruzi-noninfected stroke patients (36.7 and 13.3%, respectively). Apical aneurysm (27.3%), left atrial dilatation (12.1%), left ventricle hypokinesia (9.4%) and right bundle branch block (36.4%) were also detected in asymptomatic T. cruzi-infected stroke patients. CONCLUSIONS: Ischemic stroke may be the first manifestation of Chagas disease in asymptomatic patients with mild left ventricle dysfunction. Other noncardioembolic stroke subtypes can occur in asymptomatic T. cruzi-infected patients.

Chagas disease is independently associated with brain atrophy.

Chagas disease (CD) remains a major cause of cardiomyopathy and stroke in developing countries. Brain involvement in CD has been attributed to left ventricular dysfunction, resulting in chronic brain ischemia due to hypoperfusion and/or embolic infarcts. However, cognitive impairment in CD may occur independently of cardiac disease. Therefore, we aimed to investigate head computed tomography (CT) findings in patients with Chagas disease cardiomyopathy (CDC) in comparison with other cardiomyopathies (OC). We studied 73 patients with CDC (n = 41) or OC (n = 32) matched for age and gender. These patients underwent head CT, rated by an investigator blinded to all clinical information. Head CT was rated for the presence of lacunar or territorial infarcts, as well as for measuring the total volumes of the brain, cerebellum and ventricles. Total brain volume was smaller in CDC as compared to OC patients (1,135 +/- 150 vs. 1,332 +/- 198 cm(3), P < 0.001). Cerebellar and ventricular volumes did not differ between the groups. The prevalence of brain infarcts did not differ significantly between the groups. Chagas disease was the only independent predictor of brain atrophy in the multivariable analysis (OR = 1.38; 95% CI = 1.06-1.79, P = 0.017). Chagas disease is associated with brain atrophy independent of structural cardiac disease related to cardiomyopathy. Brain atrophy, rather than multiple infarcts, may represent the main anatomical substrate of cognitive impairment in Chagas disease.

Cardiopulmonary manifestations of hepatosplenic schistosomiasis.

BACKGROUND: Schistosomiasis is a highly prevalent disease with >200 million infected people. Pulmonary hypertension is one of the pulmonary manifestations in this disease, particularly in its hepatosplenic presentation. The aim of this study was to determine the prevalence of pulmonary hypertension in schistosomiasis patients with the hepatosplenic form of the disease. METHODS AND RESULTS: All patients with hepatosplenic schistosomiasis followed up at the gastroenterology department of our university hospital underwent echocardiographic evaluation to search for pulmonary hypertension. Patients presenting with systolic pulmonary artery pressure >40 mm Hg were further evaluated through right heart catheterization. Our study showed an 18.5% prevalence of patients with elevated systolic pulmonary artery pressure at echocardiography. Invasive hemodynamics confirmed the presence of pulmonary hypertension in 7.7% (95% confidence interval, 3.3 to 16.7) of patients, with a prevalence of precapillary (arterial) pulmonary hypertension of 4.6% (95% confidence interval, 1.5 to 12.7). CONCLUSIONS: Our study reinforces the role of echocardiography as a screening tool in the investigation of pulmonary hypertension, together with the need for invasive monitoring for a proper diagnosis. We conclude that hepatosplenic schistosomiasis may account for one of the most prevalent forms of pulmonary hypertension worldwide, justifying the development of further studies to evaluate the effect of specific pulmonary hypertension treatment in this particular form of the disease.

Cardiac involvement of Echinococcus granulosus evaluated by multi-contrast CMR imaging.

Cardiac manifestations of hydatid cysts are rare and occur in about 0.2 to 3% of all cases of human hydatidosis. We report the case of a young man with a known 4-year old infection with Echinoccus granulosus. Cardiovascular magnetic resonance imaging (CMR) was performed and showed two cysts in the left ventricular wall. The smaller cyst had a thin, noncontinuous membrane to the left ventricle. The T1- and T2-weighted images showed an isointense signal of the cysts compared to blood; fat-suppressed images showed no fatty components. To highlight the potential small signal differences we assigned the contents of the gray images to red, green and blue channels of a conventional color image. Blood and the content of the cysts had the same color, making a connection between the cysts and the LV blood pool highly probable. This was confirmed by first pass perfusion imaging, which showed simultaneous contrast agent arrival in the left ventricular cavity and the cysts. Delayed enhancement (DE) revealed fibrotic tissue surrounding the cysts. MR seems to be the most complete method of diagnosing the disease, as anatomical structures, type of content of the cyst (liquid or solid) and its relation to the myocardium can be assessed within one study.

Coronary artery bypass in myocardial ischemia of the young due to hydatid cyst.

Cardiac hydatid cyst is an uncommon disease, especially in France. It is rarely responsible for myocardial ischemia, and even more rarely in the young. We report the clinical features and imaging of a 24-year-old Tunisian woman with hydatid cyst of the free wall of the left ventricle responsible for myocardial ischemia, associated with a hepatic hydatid cyst. Management consisted of a combination of surgery with cystopericystectomy and coronary artery bypass graft and prolonged medical treatment as for treatment of hepatic hydatid cyst. Three-year follow-up revealed no recurrence. This case illustrates two interesting points: the rare clinical presentation of cardiac hydatid cyst with a coronary syndrome in a young 24-year-old woman related to compression of the left anterior descending artery by the cyst with a need for coronary artery bypass graft after resection of the cyst, and the value of medical treatment of hydatid disease, even for cardiac localization.

Left ventricular circulatory support as bridge to heart transplantation in Chagas' disease cardiomyopathy.

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.

Large hydatic cyst of the left ventricle associated with syncopal attacks.

An unusual case of giant hydatic cyst of the left ventricle producing cardiac and systemic symptomatology is described. The patient had suffered presyncopal and syncopal attacks and the final diagnosis was made by combination of echocardiography, magnetic resonance imaging and serological tests. Surgical resection of the cyst supplemented by medical therapy yielded favorable results.

Dyskinesis in Chagasic myocardium: centerline analysis of wall motion using cardiac-gated magnetic resonance images of mice.

We report on the use of centerline analysis of cardiac-gated magnetic resonance images to measure wall motion abnormalities in mice infected with Trypanosoma cruzi. To our knowledge, this is the first report of segmental wall motion abnormalities in an animal model of Chagas' disease. Chagas' disease patients with severe cardiac involvement exhibit mild hypokinesis in an extensive region of the left ventricle and dyskinesis in the apical region. We observed dyskinetic segments in a similar region of the hearts of infected wild-type mice. Dyskinesis was not observed in infected mice lacking macrophage inflammatory protein-1alpha, a chemokine that may play an important role in the cardiac remodeling that is normally observed in mouse models of Chagas' disease and in human patients. This study aimed to demonstrate the utility of cardiac-gated magnetic resonance imaging and centerline analysis as a straightforward method for monitoring regional left ventricular wall motion in transgenic and/or diseased mice.

Chronotropic incompetence and abnormal autonomic modulation in ambulatory Chagas disease patients.

BACKGROUND: Chagas disease (ChD) patients might present chronotropic incompetence during exercise, although its physiopathology remains uncertain. We evaluated the heart rate (HR) response to exercise testing in ChD patients in order to determine the role of autonomic modulation and left ventricular dysfunction in the physiopathology of chronotropic incompetence. METHODS: ChD ambulatory patients (n = 170) and healthy controls (n = 24) underwent a standardized protocol including Doppler echocardiography, Holter monitoring, HR variability analysis, brain natriuretic peptide (BNP) measurement, and maximal exercise testing. The chronotropic response was calculated as the percentage of predicted HR achieved and the HR increment (DeltaHR) during exercise. ChD patients were divided according to the absence or presence of cardiopathy and chronotropic incompetence (<85% predicted HR). RESULTS: Chronotropic incompetence was present in 34 (20%) of all ChD patients. The group with cardiopathy displayed reduced DeltaHR (91 +/- 19 bpm) during exercise in comparison with ChD patients without cardiopathy (100 +/- 19 bpm). Both the values observed in ChD groups were significantly different from those of controls (112 +/- 13 bpm). Exercise duration, maximal oxygen consumption, and systolic blood pressure increment were significantly reduced in patients with abnormal chronotropic response. DeltaHR during the exercise was significantly correlated with markers of autonomic control of sinus node, such as rest HR (r =-0.498, P

Diastolic function in Chagas' disease: an echo and tissue Doppler imaging study.

AIMS: With the purpose of studying left ventricular filling in Chagas' disease (Chd), we evaluated 169 patients with Chd using echocardiography and Doppler and tissue Doppler imaging (TDI). METHODS AND RESULTS: The patients were divided into four groups according to the pattern of left ventricular filling: Group 0--normal filling pattern, Group 1--abnormal relaxation, Group 2--pseudonormal flow pattern, and Group 3--restrictive pattern. All patients were submitted to TDI of the basal portion of the left ventricle's walls. Diastolic dysfunction was found in 21.3% of the patients, with a strong correlation between the worsening of diastolic function and ejection fraction (r = 0.78, P < 0.001). TDI septal e' wave measurement was the best method for the detection of any kind of diastolic dysfunction. Considering a cut-off point of 11 cm/s, a reduced e' wave value has 97% sensitivity, 84% specificity, 62% positive predictive value, and 99% negative predictive value. The septal E/e' ratio was the best index for the detection of advanced diastolic dysfunction. Considering a cut-point of 7.2, an elevated E/e' ratio has 100% sensitivity, 88% specificity, 54.2% positive predictive value, and 100% negative predictive value. CONCLUSION: This study showed the characterization of the various patterns of left ventricle diastolic function by echocardiography and Doppler in Chagas' disease and the usefulness of TDI in the assessment of diagnosis of diastolic dysfunction in this disease.

Predictors of unfavourable prognosis in chronic Chagas' disease.

The aim of this study was to detect clinical predictors of left ventricular dysfunction, left ventricular dilatation and apical aneurysm on echocardiography, all known as independent predictors of lethal outcome for patients with chronic Chagas' disease. Seventy-four patients with a positive complement-fixation test for Chagas' disease participated; 44 (59%) had left ventricular dysfunction, 41 (55%) left ventricular dilatation and 15 (20%) apical aneurysm. A stepwise logistic regression analysis showed that systolic blood pressure (P < 0.001) and male sex (P < 0.001) were independent predictors of left ventricular dilatation on echocardiography. A receiver-operating characteristic curve provided a systolic blood pressure of 120 mmHg with a sensitivity of 70% and a specificity of 63% to predict left ventricular dilatation. The combination of male sex and systolic blood pressure of 120 mmHg had a sensitivity of 56% and a specificity of 91% to predict left ventricular dilatation. In a separate stepwise logistic regression analysis, left ventricular systolic dysfunction was independently predicted by systolic blood pressure (P = 0.006) and New York Heart Association functional class (P = 0.01). Receiver-operating curves provided a blood pressure of 120 mmHg with a sensitivity of 72% and a specificity of 59% to predict left ventricular dysfunction, whereas a New York Heart Association functional score of 2 predicted left ventricular systolic dysfunction with a sensitivity of 78% and a specificity of 50%. The combination of New York Heart Association functional class and a systolic blood pressure of 120 mmHg predicted left ventricular dysfunction with a sensitivity of 59% and a specificity of 77%. The apical aneurysm was independently predicted by myocardial necrosis on the resting ECG, but only with a sensitivity of 20%. Hence, echocardiographic markers of cardiac mortality and sudden cardiac death in Chagas' disease can be independently predicted by clinical examination. This may be useful for screening high-risk chagasic patients.