Life expectancy analysis in patients with Chagas' disease: prognosis after one decade (1973-1983)

Chagas disease is related to structural changes of the gut microbiota in adults with chronic infection (TRIPOBIOME Study)

BACKGROUND

The implications of the gut microbial communities in the immune response against parasites and gut motility could explain the differences in clinical manifestations and treatment responses found in patients with chronic Chagas disease.

METHODOLOGY/PRINCIPAL FINDINGS

In this pilot prospective cross-sectional study, we included 80 participants: 29 with indeterminate CD (ICD), 16 with cardiac CD (CCD), 15 with digestive CD (DCD), and 20 controls without CD. Stool was collected at the baseline visit and faecal microbial community structure DNA was analyzed by whole genome sequencing. We also performed a comprehensive dietary analysis. Ninety per cent (72/80) of subjects were of Bolivian origin with a median age of 47 years (IQR 39-54) and 48.3% (29/60) had received benznidazole treatment. There were no substantial differences in dietary habits between patients with CD and controls. We identified that the presence or absence of CD explained 5% of the observed microbiota variability. Subjects with CD exhibited consistent enrichment of Parabacteroides spp, while for Enterococcus hirae, Lactobacillus buchneri and Megamonas spp, the effect was less clear once excluded the outliers values. Sex, type of visceral involvement and previous treatment with benznidazole did not appear to have a confounding effect on gut microbiota structure. We also found that patients with DCD showed consistent Prevotella spp enrichment.

CONCLUSIONS

We found a detectable effect of Chagas disease on overall microbiota structure with several potential disease biomarkers, which warrants further research in this field. The analysis of bacterial diversity could prove to be a viable target to improve the prognosis of this prevalent and neglected disease.

Management of Cardiovascular Disease in Patients With COVID-19 and Chronic Chagas Disease: Implications to Prevent a Scourge Still Larger

Cardiovascular diseases (CVD) are the most important cause of morbidity and mortality in the general population. Because the high prevalence of COVID-19 and chronic Chagas disease (CCD) where the latter is endemic, all such diseases will likely be observed in the same patient. While COVID-19 can provoke generalized endotheliitis, which can lead to a cytokine storm and a hyper-coagulable state culminating into in-site and at a distance thrombosis. Therefore, small-vessel coronary artery disease (CAD), cerebrovascular disease, thromboembolism, and arrhythmias are prominent findings in COVID-19. In CCD, small-vessel CAD, cardioembolic stroke, pulmonary embolism, heart failure and arrhythmias are frequently observed as a result of a similar but less intense mechanism. Consequently, the association of CCD and COVID-19 will likely increase the incidence of CVD. Thus, doctors on the frontline should be on the alert for this diagnostic possibility so that the proper treatment can be given without any delay.

Prognosis of chronic Chagas heart disease and other pending clinical challenges

In this chapter, the main prognostic markers of Chagas heart disease are addressed, with an emphasis on the most recent findings and questions, establishing the basis for a broad discussion of recommendations and new approaches to managing Chagas cardiopathy. The main biological and genetic markers and the contribution of the electrocardiogram, echocardiogram and cardiac magnetic resonance are presented. We also discuss the most recent therapeutic proposals for heart failure, thromboembolism and arrhythmias, as well as current experience in heart transplantation in patients suffering from severe Chagas cardiomyopathy. The clinical and epidemiological challenges introduced by acute Chagas disease due to oral contamination are discussed. In addition, we highlight the importance of ageing and comorbidities in influencing the outcome of chronic Chagas heart disease. Finally, we discuss the importance of public policies, the vital role of funding agencies, universities, the scientific community and health professionals, and the application of new technologies in finding solutions for better management of Chagas heart disease.

Incidence and Predictors of Progression to Chagas Cardiomyopathy: Long-Term Follow-Up of Trypanosoma cruzi-Seropositive Individuals

BACKGROUND

There are few contemporary cohorts of Trypanosoma cruzi-seropositive individuals, and the basic clinical epidemiology of Chagas disease is poorly understood. Herein, we report the incidence of cardiomyopathy and death associated with T. cruzi seropositivity.

METHODS

Participants were selected in blood banks at 2 Brazilian centers. Cases were defined as T. cruzi-seropositive blood donors. T. cruzi-seronegative controls were matched for age, sex, and period of donation. Patients with established Chagas cardiomyopathy were recruited from a tertiary outpatient service. Participants underwent medical examination, blood collection, ECG, and echocardiogram at enrollment (2008-2010) and at follow-up (2018-2019). The primary outcomes were all-cause mortality and development of cardiomyopathy, defined as the presence of a left ventricular ejection fraction <50% or QRS complex duration ≥120 ms, or both. To handle loss to follow-up, a sensitivity analysis was performed using inverse probability weights for selection.

RESULTS

We enrolled 499 T. cruzi-seropositive donors (age 48±10 years, 52% male), 488 T. cruzi-seronegative donors (age 49±10 years, 49% male), and 101 patients with established Chagas cardiomyopathy (age 48±8 years, 59% male). The mortality in patients with established cardiomyopathy was 80.9 deaths/1000 person-years (py) (54/101, 53%) and 15.1 deaths/1000 py (17/114, 15%) in T. cruzi-seropositive donors with cardiomyopathy at baseline. Among T. cruzi-seropositive donors without cardiomyopathy at baseline, mortality was 3.7 events/1000 py (15/385, 4%), which was no different from T. cruzi-seronegative donors with 3.6 deaths/1000 py (17/488, 3%). The incidence of cardiomyopathy in T. cruzi-seropositive donors was 13.8 (95% CI, 9.5-19.6) events/1000 py (32/262, 12%) compared with 4.6 (95% CI, 2.3-8.3) events/1000 py (11/277, 4%) in seronegative controls, with an absolute incidence difference associated with T. cruzi seropositivity of 9.2 (95% CI, 3.6-15.0) events/1000 py. T. cruzi antibody level at baseline was associated with development of cardiomyopathy (adjusted odds ratio, 1.4 [95% CI, 1.1-1.8]).

CONCLUSIONS

We present a comprehensive description of the natural history of T. cruzi seropositivity in a contemporary patient population. The results highlight the central importance of anti-T. cruzi antibody titer as a marker of Chagas disease activity and risk of progression.

Age-related anomalies of electrocardiograms in patients from areas with differential Seroprevalence of Chagas disease in Southern Bolivia

Introduction

Chagas disease currently affects some 6 million people around the world. At the chronic stage, cardiomyopathy occurs in about 20–30% of infested people. Most prevalence studies have focused on young to adult people due to the drastic consequences of acquiring the pathogen and the possibility to cure the disease at this age; the prevalence of this disease, the effect of patients' sex and the consequences to senescent people have been largely neglected. This study looks to characterize the seroprevalence of Chagas disease and its relation with occurrence of electrocardiographic anomalies associated with sex and age, and to compare rural and urban populations in Bolivia.

Methodology

Seroprevalence of Chagas disease was determined in blood samples and electrocardiograms were performed on seropositive individuals.

Results

The rural population showed higher seroprevalence than the urban population (92% and 40%, respectively). The proportion of Chagasic cardiac anomalies in seropositive persons was highest in patients of the 50–59 age group (36%) as compared with the 40–49 (8%) and the ≥60 (17%) age groups.

Conclusions

Higher seroprevalence in rural population was attributable to a higher probability to encounter the vector in rural areas. Increased exposure to infection and to development of the disease symptoms together with increased lethality of the disease as patients age explains the age-related Chagasic electrocardiographic anomalies. Since rural and urban populations showed different reactions under Chagas disease and the rural population was mainly of guaraní stock, the genetic and environmental determinants of the results should be further explored.

The course of patients with Chagas heart disease during episodes of decompensated heart failure

AIMS

This study aimed to analyse the clinical presentation and prognosis of patients with Chagas cardiomyopathy and decompensated heart failure (HF), as compared with other aetiologies.

METHODS AND RESULTS

A prospective cohort of patients admitted with decompensated HF. We included 767 patients (63.9% male), with median age of 58 years [interquartile range 48.2-66.7 years]. Main aetiologies were non-Chagas/non-ischaemic cardiomyopathies in 389 (50.7%) patients, ischaemic disease in 209 (27.2%), and Chagas disease in 169 (22%). Median left ventricular ejection fraction was 26% (interquartile range 22-35%). Patients with Chagas differed from both patients with non-Chagas/non-ischaemic and ischaemic cardiomyopathies for a higher proportion of cardiogenic shock at admission (17.8%, 11.6%, and 11%, respectively, P < 0.001) and had lower blood pressure at admission (systolic blood pressure 90 [80-102.5], 100 [85-110], and 100 [88.2-120] mmHg, P < 0.001) and lower heart rate (heart rate 71 [60-80], 87 [70-102], and 79 [64-96.5] b.p.m., P < 0.001). Further, patients with Chagas had higher serum BNP level (1544 [734-3148], 1061 [465-239], and 927 [369-1455] pg/mL, P < 0.001), higher serum bilirubin (1.4 [0.922.44], 1.2 [0.77-2.19], and 0.84 [0.49-1.45] mg/dL, P < 0.001), larger left ventricular diameter (68 [63-73], 67 [58-74], and 62 [56.8-68.3] mm, respectively, P < 0.001), lower left ventricular ejection fraction (25 [21-30]%, 26 [22-35]%, and 30 [25-38]%, P < 0.001), and a higher proportion of patients with right ventricular function (48.8%, 40.7%, and 25.9%, P < 0.001). Patients with Chagas disease were more likely to receive inotropes than patients with non-Chagas/non-ischaemic and ischaemic cardiomyopathies (77.5%, 67.5%, and 62.5%, respectively, P = 0.007) and also to receive intra-aortic balloon pumping (30.8%, 16.2%, and 10.5%, P < 0.001). Overall, the rates of death or urgent transplant were higher among patients with Chagas than in other aetiologies, a difference that was driven mostly due to increased rate of heart transplant during hospital admission (20.2%, 10.3%, and 8.1%). The prognosis of patients at 180 days after hospital admission was worse for patients with Chagas disease as compared with other aetiologies. In patients with Chagas, age [odds ratio (OR) = 0.934, confidence interval (CI)_95% 0.901-0.982, P = 0.005], right ventricular dysfunction by echocardiography (OR = 2.68, CI_95% 1.055-6.81, P = 0.016), and urea (OR = 1.009, CI_95% 1.001-1.018, P = 0.038) were significantly associated with prognosis.

CONCLUSIONS

Patients with Chagas cardiomyopathy and decompensated HF have a distinct clinical presentation and worse prognosis compared with other aetiologies.

Risk of Chronic Cardiomyopathy Among Patients With the Acute Phase or Indeterminate Form of Chagas Disease: A Systematic Review and Meta-analysis

Importance

Chagas cardiomyopathy is associated with substantial morbidity and mortality. Precise estimates of the risk of developing cardiomyopathy among patients with the acute or indeterminate chronic forms of Chagas disease are lacking.

Objective

To estimate the risk of developing chronic cardiomyopathy in patients with acute and indeterminate chronic forms of Chagas disease.

Data Sources

A systematic search in the Cochrane Library, Embase, Latin American and Caribbean Health Sciences Literature (LILACS), Medline, and Web of Science Core Collection databases was conducted from October 8 to October 24, 2018. Studies published between January 1, 1946, and October 24, 2018, that were written in the English, Spanish, and Portuguese languages were included. Search terms included Chagas disease; development of cardiomyopathy; latency duration; and determinants of the Chagas latency period.

Study Selection

Longitudinal observational studies of participants diagnosed with the acute phase of Chagas infection or the indeterminate chronic form of Chagas disease who were followed up until the development of cardiomyopathy were included. Studies were excluded if they did not provide sufficient outcome data. Of 10 761 records initially screened, 32 studies met the criteria for analysis.

Data Extraction and Synthesis

Critical appraisals of studies were performed using checklists from the Joanna Briggs Institute Reviewer's Manual, and data were collected from published studies. A random-effects meta-analysis was used to obtain pooled estimated annual rates. Data were analyzed from September 11 to December 4, 2019. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline for the registration of the protocol, data collection and integrity, assessment of bias, and sensitivity analyses.

Main Outcomes and Measures

Main outcomes were defined as the composite of the development of any new arrhythmias or changes in electrocardiogram results, dilated cardiomyopathy and segmental wall motion abnormalities in echocardiogram results, and mortality associated with Chagas disease.

Results

A total of 5005 records were screened for eligibility. Of those, 298 full-text articles were reviewed, and 178 of those articles were considered for inclusion in the quantitative synthesis. After exclusions, 32 studies that included longitudinal observational outcomes were selected for the analysis; 23 of those studies comprised patients with the indeterminate chronic form of Chagas disease, and 9 of those studies comprised patients in the acute phase of Chagas infection. The analysis indicated that the pooled estimated annual rate of cardiomyopathy development was 1.9% (95% CI, 1.3%-3.0%; I2 = 98.0%; τ2 [ln scale] = 0.9992) in patients with indeterminate chronic Chagas disease and 4.6% (95% CI, 2.7%-7.9%; I2 = 86.6%; τ2 [ln scale] = 0.4946) in patients with acute Chagas infection.

Conclusions and Relevance

Patients with the indeterminate chronic form of Chagas disease had a significant annual risk of developing cardiomyopathy. The annual risk was more than double among patients in the acute phase of Chagas infection.

Progression Rate from the Indeterminate Form to the Cardiac Form in Patients with Chronic Chagas Disease: Twenty-Two-Year Follow-Up in a Brazilian Urban Cohort

Most patients with chronic Chagas disease (CD) present the indeterminate form and are at risk to develop the cardiac form. However, the actual rate of progression to the cardiac form is still unknown. Methods: In total, 550 patients with the indeterminate CD form were followed by means of annual electrocardiogram at our outpatient clinic. The studied endpoint was progression to cardiac form defined by the appearance of electrocardiographic changes typical of CD. The progression rate was calculated as the cumulative progression rate and the incidence progression rate per 100 patient years. Results: Thirty-seven patients progressed to the CD cardiac form within a mean of 73 ± 48 months of follow-up, which resulted in a 6.9% cumulative progression rate and incidence rate of 1.48 cases/100 patient years. Patients who progressed were older (mean age 47.8 ± 12.2 years), had a higher prevalence of associated heart diseases (p < 0.0001), positive xenodiagnosis (p = 0.007), and were born in the most endemic Brazilian states (p = 0.018). Previous co-morbidities remained the only variable associated with CD progression after multivariate Cox proportional hazards regression analysis (p = 0.002). Conclusion: The progression rate to chronic CD cardiac form is low and inferior to rates previously reported in other studies.

Risk Score for Predicting 2-Year Mortality in Patients With Chagas Cardiomyopathy From Endemic Areas: SaMi-Trop Cohort Study

Background

Risk stratification of Chagas disease patients in the limited‐resource setting would be helpful in crafting management strategies. We developed a score to predict 2‐year mortality in patients with Chagas cardiomyopathy from remote endemic areas.

Methods and Results

This study enrolled 1551 patients with Chagas cardiomyopathy from Minas Gerais State, Brazil, from the SaMi‐Trop cohort (The São Paulo‐Minas Gerais Tropical Medicine Research Center). Clinical evaluation, ECG, and NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) were performed. A Cox proportional hazards model was used to develop a prediction model based on the key predictors. The end point was all‐cause mortality. The patients were classified into 3 risk categories at baseline (low, <2%; intermediate, ≥2% to 10%; high, ≥10%). External validation was performed by applying the score to an independent population with Chagas disease. After 2 years of follow‐up, 110 patients died, with an overall mortality rate of 3.505 deaths per 100 person‐years. Based on the nomogram, the independent predictors of mortality were assigned points: age (10 points per decade), New York Heart Association functional class higher than I (15 points), heart rate ≥80 beats/min (20 points), QRS duration ≥150 ms (15 points), and abnormal NT‐proBNP adjusted by age (55 points). The observed mortality rates in the low‐, intermediate‐, and high‐risk groups were 0%, 3.6%, and 32.7%, respectively, in the derivation cohort and 3.2%, 8.7%, and 19.1%, respectively, in the validation cohort. The discrimination of the score was good in the development cohort (C statistic: 0.82), and validation cohort (C statistic: 0.71).

Conclusions

In a large population of patients with Chagas cardiomyopathy, a combination of risk factors accurately predicted early mortality. This helpful simple score could be used in remote areas with limited technological resources.

Renal denervation in patients with heart failure secondary to Chagas' disease: A pilot randomized controlled trial

INTRODUCTION

Chagas disease is one of the most relevant endemic parasitic diseases in Latin America, affecting approximately 6 million people. Overt Chagas heart disease is an ominous condition, occurring in 20-30% of infected individuals, which has besides the persistent myocarditis a peculiar intracardiac ganglionic neuronal depletion and dysautonomy. This study aims to evaluate the safety and feasibility of renal denervation for patients with advanced symptomatic Chagas cardiomyopathy.

METHODS

Open-label prospective pilot study that randomized patients with Chagas heart disease to either renal denervation or conservative treatment (2:1 ratio). The primary endpoint was the incidence of major adverse events at 9 months, defined as a composite of all-cause death, myocardial infarction, stroke, need for renal artery invasive treatment, or worsening renal function.

RESULTS

A total of 17 patients were allocated for renal denervation (n = 11) or conservative treatment (n = 6). Included patients had severe symptomatic heart disease, with markedly depressed left ventricular function (average ejection fraction 26.7 ± 4.9%). For patients randomized to renal denervation, the procedure was performed successfully and uneventfully. After 9 months, the primary endpoint occurred in 36.4% of patients in the renal denervation group and 50.0% in the control arm (p = .6). After 9 months, clinical, laboratory, functional, echocardiographic, and quality of life parameters were similar between groups.

CONCLUSIONS

This pilot study suggests that renal denervation is safe and feasible in patients with Chagas cardiomyopathy, warranting future studies to better evaluate the clinical efficacy of the interventional strategy in improving the prognosis of this high-risk population.

Electrocardiogram in Chagas disease

Since the initial descriptions of Chagas cardiomyopathy (ChCM), the electrocardiography has played a key role in patient evaluations. The diagnostic criterion of chronic ChCM is the presence of characteristic electrocardiographic (ECG) abnormalities in seropositive individuals, regardless of the presence of symptoms. However, these ECG abnormalities are rarely specific to ChCM and, particularly among the elderly, can be caused by other simultaneous cardiomyopathies. ECG abnormalities can predict the occurrence of heart failure, stroke, and even death. Nevertheless, most prognostic studies have included Chagas disease (ChD) populations and, not exclusively, ChCM. Thus, more studies are required to evaluate the efficacy of ECG in predicting reliable prognoses in established chronic ChCM. This review exclusively discusses the role of the 12-lead ECG in the clinical evaluation of chronic ChD.

Chagas Cardiomyopathy: An Update of Current Clinical Knowledge and Management: A Scientific Statement From the American Heart Association

Background:

Chagas disease, resulting from the protozoan Trypanosoma cruzi , is an important cause of heart failure, stroke, arrhythmia, and sudden death. Traditionally regarded as a tropical disease found only in Central America and South America, Chagas disease now affects at least 300 000 residents of the United States and is growing in prevalence in other traditionally nonendemic areas. Healthcare providers and health systems outside of Latin America need to be equipped to recognize, diagnose, and treat Chagas disease and to prevent further disease transmission.

Methods and Results:

The American Heart Association and the Inter-American Society of Cardiology commissioned this statement to increase global awareness among providers who may encounter patients with Chagas disease outside of traditionally endemic environments. In this document, we summarize the most updated information on diagnosis, screening, and treatment of T cruzi infection, focusing primarily on its cardiovascular aspects. This document also provides quick reference tables, highlighting salient considerations for a patient with suspected or confirmed Chagas disease.

Conclusions:

This statement provides a broad summary of current knowledge and practice in the diagnosis and management of Chagas cardiomyopathy. It is our intent that this document will serve to increase the recognition of Chagas cardiomyopathy in low-prevalence areas and to improve care for patients with Chagas heart disease around the world.

Chagas disease

Chagas disease is an anthropozoonosis from the American continent that has spread from its original boundaries through migration. It is caused by the protozoan Trypanosoma cruzi, which was identified in the first decade of the 20th century. Once acute infection resolves, patients can develop chronic disease, which in up to 30-40% of cases is characterised by cardiomyopathy, arrhythmias, megaviscera, and, more rarely, polyneuropathy and stroke. Even after more than a century, many challenges remain unresolved, since epidemiological control and diagnostic, therapeutic, and prognostic methods must be improved. In particular, the efficacy and tolerability profile of therapeutic agents is far from ideal. Furthermore, the population affected is older and more complex (eg, immunosuppressed patients and patients with cancer). Nevertheless, in recent years, our knowledge of Chagas disease has expanded, and the international networking needed to change the course of this deadly disease during the 21st century has begun.

Chronic Chagas Heart Disease Management: From Etiology to Cardiomyopathy Treatment

Trypanosoma cruzi (T. cruzi) infection is endemic in Latin America and is becoming a worldwide health burden. It may lead to heterogeneous phenotypes. Early diagnosis of T. cruzi infection is crucial. Several biomarkers have been reported in Chagas heart disease (ChHD), but most are nonspecific for T. cruzi infection. Prognosis of ChHD patients is worse compared with other etiologies, with sudden cardiac death as an important mode of death. Most ChHD patients display diffuse myocarditis with fibrosis and hypertrophy. The remodeling process seems to be associated with etiopathogenic mechanisms and neurohormonal activation. Pharmacological treatment and antiarrhythmic therapy for ChHD is mostly based on results for other etiologies. Heart transplantation is an established, valuable therapeutic option in refractory ChHD. Implantable cardioverter-defibrillators are indicated for prevention of secondary sudden cardiac death. Specific etiological treatments should be revisited and reserved for select patients. Understanding and management of ChHD need improvement, including development of randomized trials.

The role of CCR5 in Chagas disease - a systematic review

Chagas disease is an infection caused by the protozoan Trypanosoma cruzi. The clinical manifestations result from the chronic forms of the disease: indeterminate, cardiac, digestive or mixed. The pathogenesis of this disease is related to the genetic variability of both the parasite and the host with polymorphisms of genes involved in immune response possibly being involved in the variable clinical course. Cytokines play a key role in regulating immune response, in particular chemokines exert a crucial role in the control of leukocyte migration during the host's response to infectious processes. Furthermore, inflammatory cytokines and chemokines have been implicated in the generation of inflammatory infiltrates and tissue damage. The involvement of the CC Chemokine Receptor 5 (CCR5) in leukocyte migration to sites of inflammation has been elucidated and this receptor has been investigated in Chagas disease. Here we review the role of CCR5 in T. cruzi infection as well as its importance in the pathogenesis of the Chagas disease.

Carlos Chagas Discoveries as a Drop Back to Scientific Construction of Chronic Chagas Heart Disease

The scientific construction of chronic Chagas heart disease (CCHD) started in 1910 when Carlos Chagas highlighted the presence of cardiac arrhythmia during physical examination of patients with chronic Chagas disease, and described a case of heart failure associated with myocardial inflammation and nests of parasites at autopsy. He described sudden cardiac death associated with arrhythmias in 1911, and its association with complete AV block detected by Jacquet's polygraph as Chagas reported in 1912. Chagas showed the presence of myocardial fibrosis underlying the clinical picture of CCHD in 1916, he presented a full characterization of the clinical aspects of CCHD in 1922. In 1928, Chagas detected fibrosis of the conductive system, and pointed out the presence of marked cardiomegaly at the chest X-Ray associated with minimal symptomatology. The use of serological reaction to diagnose CCHD was put into clinical practice in 1936, after Chagas' death, which along with the 12-lead ECG, revealed the epidemiological importance of CCHD in 1945. In 1953, the long period between initial infection and appearance of CCHD was established, whereas the annual incidence of CCHD from patients with the indeterminate form of the disease was established in 1956. The use of heart catheterization in 1965, exercise stress testing in 1973, Holter monitoring in 1975, Electrophysiologic testing in 1973, echocardiography in 1975, endomyocardial biopsy in 1981, and Magnetic Resonance Imaging in 1995, added to the fundamental clinical aspects of CCHD as described by Carlos Chagas.

Increased mortality attributed to Chagas disease: a systematic review and meta-analysis

BACKGROUND

The clinical outcomes associated with Chagas disease remain poorly understood. In addition to the burden of morbidity, the burden of mortality due to Trypanosoma cruzi infection can be substantial, yet its quantification has eluded rigorous scrutiny. This is partly due to considerable heterogeneity between studies, which can influence the resulting estimates. There is a pressing need for accurate estimates of mortality due to Chagas disease that can be used to improve mathematical modelling, burden of disease evaluations, and cost-effectiveness studies.

METHODS

A systematic literature review was conducted to select observational studies comparing mortality in populations with and without a diagnosis of Chagas disease using the PubMed, MEDLINE, EMBASE, Web of Science and LILACS databases, without restrictions on language or date of publication. The primary outcome of interest was mortality (as all-cause mortality, sudden cardiac death, heart transplant or cardiovascular deaths). Data were analysed using a random-effects model to obtain the relative risk (RR) of mortality, the attributable risk percent (ARP), and the annual mortality rates (AMR). The statistic I(2) (proportion of variance in the meta-analysis due to study heterogeneity) was calculated. Sensitivity analyses and publication bias test were also conducted.

RESULTS

Twenty five studies were selected for quantitative analysis, providing data on 10,638 patients, 53,346 patient-years of follow-up, and 2739 events. Pooled estimates revealed that Chagas disease patients have significantly higher AMR compared with non-Chagas disease patients (0.18 versus 0.10; RR = 1.74, 95% CI 1.49-2.03). Substantial heterogeneity was found among studies (I(2) = 67.3%). The ARP above background mortality was 42.5%. Through a sub-analysis patients were classified by clinical group (severe, moderate, asymptomatic). While RR did not differ significantly between clinical groups, important differences in AMR were found: AMR = 0.43 in Chagas vs. 0.29 in non-Chagas patients (RR = 1.40, 95% CI 1.21-1.62) in the severe group; AMR = 0.16 (Chagas) vs. 0.08 (non-Chagas) (RR = 2.10, 95% CI 1.52-2.91) in the moderate group, and AMR = 0.02 vs. 0.01 (RR = 1.42, 95% CI 1.14-1.77) in the asymptomatic group. Meta-regression showed no evidence of study-level covariates on the effect size. Publication bias was not statistically significant (Egger's test p=0.08).

CONCLUSIONS

The results indicate a statistically significant excess of mortality due to Chagas disease that is shared among both symptomatic and asymptomatic populations.

Chagas Heart Failure in Patients from Latin America

Physicians working in Europe and the United States should suspect Chagas heart failure in every patient coming from Latin America with chronic heart failure. Diagnosis should be confirmed by positive serology. Right bundle branch block and left anterior fascicular block on 12-lead electrocardiogram, enlarged cardiac silhouette with no pulmonary congestion on chest X-ray and left ventricular apical aneurysm on echocardiography are the distinctive features of this condition. The clinical course is poorer than that of non-Chagas heart failure; however, medical treatment is similar. Implantable cardioverter-defibrillators are useful in the primary and secondary prevention of sudden cardiac death. Cardiac resynchronisation therapy can be given to patients on optimal medical therapy and with lengthened QRS complex. Heart transplantation is the treatment of choice for patients with end-stage Chagas heart failure.

Trypanosoma cruzi infection in genetically selected mouse lines: genetic linkage with quantitative trait locus controlling antibody response

Trypanosoma cruzi infection was studied in mouse lines selected for maximal (AIRmax) or minimal (AIRmin) acute inflammatory reaction and for high (H_III) or low (L_III) antibody (Ab) responses to complex antigens. Resistance was associated with gender (females) and strain—the high responder lines AIRmax and H_III were resistant. The higher resistance of H_III as compared to L_III mice extended to higher infective doses and was correlated with enhanced production of IFN-γ and nitric oxide production by peritoneal and lymph node cells, in H_III males and females. We also analyzed the involvement of previously mapped Ab and T. cruzi response QTL with the survival of Selection III mice to T. cruzi infections in a segregating backcross [F1(H_III×L_III) ×L_III] population. An Ab production QTL marker mapping to mouse chromosome 1 (34.8 cM) significantly cosegregated with survival after acute T. cruzi infections, indicating that this region also harbors genes whose alleles modulate resistance to acute T. cruzi infection.

The use of a heterogeneously controlled mouse population reveals a significant correlation of acute phase parasitemia with mortality in Chagas disease

Chagas disease develops upon infection with the protozoan parasite Trypanosoma cruzi and undergoes an acute phase characterized by massive parasite replication and the presence of parasites in the blood. This condition is known as acute phase parasitemia. This initial stage may result in a cure, in the development of the chronic stages of the disease or in the death of the infected host. Despite intensive investigation related to the characterization of the acute and chronic phases of the disease, the cause-effect relationship of acute phase parasitemia to the outcome of the disease is still poorly understood. In this study, we artificially generated a heterogeneously controlled mouse population by intercrossing F1 mice obtained from a parental breeding of highly susceptible A/J with highly resistant C57BL/6 mouse strains. This F2 population was infected and used to assess the correlation of acute phase parasitemia with the longevity of the animals. We used nonparametric statistical analyses and found a significant association between parasitemia and mortality. If males and females were evaluated separately, we found that the former were more susceptible to death, although parasitemia was similar in males and females. In females, we found a strong negative correlation between parasitemia and longevity. In males, however, additional factors independent of parasitemia may favor mouse mortality during the development of the disease. The correlations of acute phase parasitemia with mortality reported in this study may facilitate an appropriate prognostic approach to the disease in humans. Moreover, these results illustrate the complexity of the mammalian genetic traits that regulate host resistance during Chagas disease.

Global economic burden of Chagas disease: a computational simulation model

BACKGROUND

As Chagas disease continues to expand beyond tropical and subtropical zones, a growing need exists to better understand its resulting economic burden to help guide stakeholders such as policy makers, funders, and product developers. We developed a Markov simulation model to estimate the global and regional health and economic burden of Chagas disease from the societal perspective.

METHODS

Our Markov model structure had a 1 year cycle length and consisted of five states: acute disease, indeterminate disease, cardiomyopathy with or without congestive heart failure, megaviscera, and death. Major model parameter inputs, including the annual probabilities of transitioning from one state to another, and present case estimates for Chagas disease came from various sources, including WHO and other epidemiological and disease-surveillance-based reports. We calculated annual and lifetime health-care costs and disability-adjusted life-years (DALYs) for individuals, countries, and regions. We used a discount rate of 3% to adjust all costs and DALYs to present-day values.

FINDINGS

On average, an infected individual incurs US$474 in health-care costs and 0·51 DALYs annually. Over his or her lifetime, an infected individual accrues an average net present value of $3456 and 3·57 DALYs. Globally, the annual burden is $627·46 million in health-care costs and 806,170 DALYs. The global net present value of currently infected individuals is $24·73 billion in health-care costs and 29,385,250 DALYs. Conversion of this burden into costs results in annual per-person costs of $4660 and lifetime per-person costs of $27,684. Global costs are $7·19 billion per year and $188·80 billion per lifetime. More than 10% of these costs emanate from the USA and Canada, where Chagas disease has not been traditionally endemic. A substantial proportion of the burden emerges from lost productivity from cardiovascular disease-induced early mortality.

INTERPRETATION

The economic burden of Chagas disease is similar to or exceeds those of other prominent diseases globally (eg, rotavirus $2·0 billion, cervical cancer $4·7 billion) even in the USA (Lyme disease $2·5 billion), where Chagas disease has not been traditionally endemic, suggesting an economic argument for more attention and efforts towards control of Chagas disease.

FUNDING

Bill & Melinda Gates Foundation, the National Institute of General Medical Sciences Models of Infectious Disease Agent Study.

Risk of cardiovascular events associated with positive serology for Chagas: a systematic review

BACKGROUND

Chagas disease affects mainly poor populations in Latin America. This review assesses the evidence on the independent risk of cardiovascular events associated with positive Chagas serology.

METHODS

We searched for studies using the following outcomes: death, stroke, new onset heart failure, heart failure hospitalization or evidence of left ventricular dysfunction. Studies comparing patients with positive serology for Chagas with a control group with a follow-up longer than 1 year were selected. The Medline, Lilacs and Embase databases were searched on 21 January 2011 without restrictions.

RESULTS

From 5236 potentially relevant studies, 25 fulfilled the inclusion criteria. Fourteen included patients with heart failure, six with severe symptoms and nine with mild symptoms or asymptomatic patients with low ejection fraction. In four studies of patients in functional class III or IV and in three studies of patients with mild symptoms, a higher risk of death was reported among those with positive serology for Chagas. Of the 11 studies of patients without symptoms or low ejection fraction, 3 showed a higher risk of mortality related to Chagas exposure. Two of these were based on the same cohort of people aged >60 years. Overall, 8 out of the 14 heart failure studies and 2 out of the 11 heart damage studies adjusted for confounding factors.

CONCLUSION

Positive serology for Chagas is associated with a higher risk of death for patients with heart failure. However, there is little evidence to link positive serology for Chagas with cardiovascular events in asymptomatic subjects.

A parent-of-origin effect determines the susceptibility of a non-informative F1 population to Trypanosoma cruzi infection in vivo

The development of Chagas disease is determined by a complex interaction between the genetic traits of both the protozoan parasite, T. cruzi, and the infected host. This process is regulated by multiple genes that control different aspects of the host-parasite interaction. While determination of the relevant genes in humans is extremely difficult, it is feasible to use inbred mouse strains to determine the genes and loci responsible for host resistance to infection. In this study, we investigated the susceptibility of several inbred mouse strains to infection with the highly virulent Y strain of T. cruzi and found a considerable difference in susceptibility between A/J and C57BL/6 mice. We explored the differences between these two mouse strains and found that the A/J strain presented higher mortality, exacerbated and uncontrolled parasitemia and distinct histopathology in the target organs, which were associated with a higher parasite burden and more extensive tissue lesions. We then employed a genetic approach to assess the pattern of inheritance of the resistance phenotype in an F1 population and detected a strong parent-of-origin effect determining the susceptibility of the F1 male mice. This effect is unlikely to result from imprinted genes because the inheritance of this susceptibility was affected by the direction of the parental crossing. Collectively, our genetic approach of using the F1 population suggests that genes contained in the murine chromosome X contribute to the natural resistance against T. cruzi infection. Future linkage studies may reveal the locus and genes participating on the host resistance process reported herein.

Modeling the economic value of a Chagas' disease therapeutic vaccine

The health burden of Chagas' disease (resulting from Trypanosoma cruzi infection) in Latin America (estimated to outweigh that of malaria by 5-fold and affect 2-6 million people in Mexico alone) has motivated development of therapeutic vaccines to prevent infection progression to severe disease. Our economic model for a Chagas' therapeutic vaccine in Mexico suggests that a vaccine would be highly cost-effective and in many cases economically dominant (providing both cost savings and health benefits) throughout a range of protection durations, severe adverse event risk, and dosing regimens and would be most likely to provide a positive return on investment if the vaccine prevented (rather than delayed) the onset of cardiomyopathy.

Clinical aspects of Chagas disease and implications for novel therapies

The interaction between the protozoan parasite Trypanosoma cruzi and the human host dates back 9000 years, as demonstrated by molecular analysis of material obtained from Andean mummies indicating the presence of the parasite's kinetoplast DNA in populations from Chile and Peru. This long-established interaction, which persists today, demonstrates that T. cruzi has established a very well adapted relationship with the human host. From a host-parasite relationship point-of-view this is desirable, however, such a high degree of adaptation is perhaps the foundation for many of the unknowns that surround this disease. Unveiling of the immunological mechanisms that underlie the establishment of pathology, identification of parasite-associated factors that determine strain-differential tissue tropism, discovery of host genetic elements that influence the development of different clinical forms of the disease, and understanding environmental factors that may influence the host-parasite interactions, are some of the key questions remaining to be answered. The response to these questions will aid in addressing some of the current challenges in Chagas disease: fulfilling the need for efficient diagnosis, developing effective prophylactic measures, discovering effective therapeutics, and finding methods to control disease progression.

[Regional left ventricular dysfunction and its association with complex ventricular arrhythmia, in chagasic patients with normal or borderline electrocardiogram]

INTRODUCTION

Sudden death is the major cause of death among chagasic patients. A significant number of fatal events in patients without apparent heart disease and borderline electrocardiogram, but with contractile ventricular dysfunction, have been documented. This work aimed to determine the association between regional dysfunction and the presence of ventricular arrhythmia in chagasic patients without apparent heart disease.

METHODS

Forty-nine patients with normal or borderline electrocardiogram were submitted to echocardiogram, exercise stress test and Holter. The presence of cardiac contractile alterations and complex ventricular arrhythmia was analyzed. Statistic analysis used the general Log-Linear model.

RESULTS

Mean age 56 years-old; 55% women. Regional ventricular dysfunction was verified in 24.5% of patients; positive Holter in 12% and exercise stress test in 18%. An association between complex ventricular arrhythmia and contractile abnormalities in the presence of mild left ventricle dysfunction was verified.

CONCLUSIONS

Regional contractile abnormalities with mild left ventricle dysfunction in Chagasic patients indicate a group with higher risk of complex ventricular arrhythmias, who require specific follow-up.

Predictors of mortality in patients with Chagas' cardiomyopathy and ventricular tachycardia not treated with implantable cardioverter-defibrillators

BACKGROUND

The natural history of the arrhythmogenic form of Chagas' heart disease is not fully understood.

METHODS

We assessed the outcome of 56 patients with Chagas' cardiomyopathy ([31 men]; mean age of 55 years; mean left ventricular ejection fraction [LVEF] 42%) presenting with either sustained ventricular tachycardia (VT) or nonsustained VT (NSVT), before therapy with implantable cardioverter-defibrillator was available at our center.

RESULTS

Over a mean follow-up of 38 ± 16 months (range, 1-61 months), 16 patients (29%) died, 11 due to sudden cardiac death (SCD), and five from progressive heart failure. Survivors and nonsurvivors had comparable baseline characteristics, except for a lower LVEF (46 ± 7% vs 31 ± 9%, P < 0.001) and a higher New York Heart Association class (P = 0.003) in those who died during follow-up. Receiver-operator characteristic curve analysis showed that an LVEF cutoff value of 38% had the best accuracy for predicting all-cause mortality and an LVEF cutoff value of 40% had the best accuracy for prediction of SCD. Using the multivariate Cox regression analysis, LVEF < 40% was the only predictor of all-cause mortality (hazard ratio [HR] 12.22, 95% confidence interval [CI] 3.46-43.17, P = 0.0001) and SCD (HR 6.58, 95% CI 1.74-24.88, P = 0.005).

CONCLUSIONS

Patients with Chagas' cardiomyopathy presenting with either sustained VT or NSVT run a major risk for mortality when had concomitant severe or even moderate LV systolic dysfunction.

Cardiac involvement with parasitic infections

Parasitic infections previously seen only in developing tropical settings can be currently diagnosed worldwide due to travel and population migration. Some parasites may directly or indirectly affect various anatomical structures of the heart, with infections manifested as myocarditis, pericarditis, pancarditis, or pulmonary hypertension. Thus, it has become quite relevant for clinicians in developed settings to consider parasitic infections in the differential diagnosis of myocardial and pericardial disease anywhere around the globe. Chagas' disease is by far the most important parasitic infection of the heart and one that it is currently considered a global parasitic infection due to the growing migration of populations from areas where these infections are highly endemic to settings where they are not endemic. Current advances in the treatment of African trypanosomiasis offer hope to prevent not only the neurological complications but also the frequently identified cardiac manifestations of this life-threatening parasitic infection. The lack of effective vaccines, optimal chemoprophylaxis, or evidence-based pharmacological therapies to control many of the parasitic diseases of the heart, in particular Chagas' disease, makes this disease one of the most important public health challenges of our time.

Canine Chagas' disease (American trypanosomiasis) in North America

Chagas' disease, or American trypanosomiasis, caused by the hemoflagellated protozoan Trypanosoma cruzi (class Zoomastigophorea and family Trypanosomatidae), is the leading cause of dilated cardiomyopathy in man. In dogs in North America, Chagas disease mainly occurs in working dogs in southeastern Texas. It is likely that most dogs become infected by eating infected vectors, causing the release of the organisms into the mouth of the host. Most dogs are diagnosed during the chronic stage of the disease, which is typified by dilated cardiomyopathy and malignant ventricular-based arrhythmias. This article reviews the etiology, epidemiology, pathogenesis, diagnosis, and available therapy for Chagas' disease in dogs.

Results of electrophysiologic studies in patients with acute Chagasic myocarditis

BACKGROUND

As the acute stage of Chagas' myocarditis is rarely detected, little is known about the electrophysiologic characteristics of that stage.

HYPOTHESIS

This investigation was undertaken to conduct an electrophysiologic study of the properties of the heart during the acute phase of Chagasic myocarditis.

METHODS

We studied eight patients who had positive xenodiagnosis, positive mice culture, and positive complement fixation test for Chagas' disease.

RESULTS

Trypanosoma cruzi were identified in all of the patients' stained blood samples. Right ventricular endomyocardial biopsies were obtained, evidencing a distinct infiltrate of lymphocytes that confirmed the diagnosis of acute myocarditis. The cardiac dimensions and the ventricular systolic and diastolic function were preserved in all patients. The electrocardiogram evidenced conduction defects in two patients. The signal-averaged electrocardiogram displayed late potentials in three patients. In the electrophysiologic study, atrial fibrillation or flutter was induced in four patients. When compared with control patients, Chagasic patients were found to have greater values of atrial threshold, A-H interval, and atrioventricular (AV) nodal effective refractory period. The H-V interval was mildly prolonged in two patients, but the dynamic AV nodal conduction was preserved (1:1 conduction during right atrial stimulation at a cycle length of 400 ms) in all the Chagasic patients. The ventricular parameters were within normal limits, and no sustained ventricular arrhythmia could be induced.

CONCLUSIONS

Patients with mild acute Chagasic myocarditis may suffer from electrical abnormalities and arrhythmias that are more evident at the supraventricular level and the AV junction.

Cardiac involvement in African and American trypanosomiasis

American trypanosomiasis (Chagas disease) and human African trypanosomiasis (HAT; sleeping sickness) are both caused by single-celled flagellates that are transmitted by arthropods. Cardiac problems are the main cause of morbidity in chronic Chagas disease, but neurological problems dominate in HAT. Physicians need to be aware of Chagas disease and HAT in patients living in or returning from endemic regions, even if they left those regions long ago. Chagas heart disease has to be taken into account in the differential diagnosis of cardiomyopathy, primarily in patients with pathological electrocardiographic (ECG) findings, such as right bundle branch block or left anterior hemiblock, with segmental wall motion abnormalities or aneurysms on echocardiography, and in young patients with stroke in the absence of arterial hypertension. In HAT patients, cardiac involvement as seen by ECG alterations, such as repolarisation changes and low voltage, is frequent. HAT cardiopathy in general is benign and does not cause relevant congestive heart failure and subsides with treatment. We review the differences between the American and African trypanosomiasis with the main focus on the heart.

Treatment of chronic systolic heart failure secondary to Chagas heart disease in the current era of heart failure therapy

The treatment of chronic heart failure secondary to Chagas disease has been based on extrapolation of data achieved in the treatment of non-Chagas disease heart failure. Because beta-blockers decrease the incidence of sudden cardiac death in non-Chagas disease heart failure and sudden cardiac death occurs preferentially in patients with mild Chagas disease heart failure, beta-blockers may be administered first to class I/II patients with Chagas disease heart failure. In advanced Chagas disease heart failure, angiotensin-converting enzyme inhibitor and diuretics may be given at first to compensate for congestive symptoms. After clinical status improvement, beta-blockers should be given at targeted doses, if necessary reducing angiotensin-converting enzyme inhibitor doses. Primary and secondary prevention of sudden cardiac death may be accomplished with implantable cardioverter defibrillators because of the high recurrence of life-threatening arrhythmias despite amiodarone administration. In refractory heart failure, heart transplantation is the treatment of choice.

Autoantibodies enhance agonist action and binding to cardiac muscarinic receptors in chronic Chagas' disease

Chronic Chagasic patient immunoglobulins (CChP-IgGs) recognize an acidic amino acid cluster at the second extracellular loop (el2) of cardiac M(2)-muscarinic acetylcholine receptors (M(2)AChRs). These residues correspond to a common binding site for various allosteric agents. We characterized the nature of the M(2)AChR/CChP-IgG interaction in functional and radioligand binding experiments applying the same mainstream strategies previously used for the characterization of other allosteric agents. Dose-response curves of acetylcholine effect on heart rate were constructed with data from isolated heart experiments in the presence of CChP or normal blood donor (NBD) sera. In these experiments, CChP sera but not NBD sera increased the efficacy of agonist action by augmenting the onset of bradyarrhythmias and inducing a Hill slope of 2.5. This effect was blocked by gallamine, an M(2)AChR allosteric antagonist. Correspondingly, CChP-IgGs increased acetylcholine affinity twofold and showed negative cooperativity for [(3)H]-N-methyl scopolamine ([(3)H]-NMS) in allosterism binding assays. A peptide corresponding to the M(2)AChR-el2 blocked this effect. Furthermore, dissociation assays showed that the effect of gallamine on the [(3)H]-NMS off-rate was reverted by CChP-IgGs. Finally, concentration-effect curves for the allosteric delay of W84 on [(3)H]-NMS dissociation right shifted from an IC(50) of 33 nmol/L to 78 nmol/L, 992 nmol/L, and 1670 nmol/L in the presence of 6.7 x 10(- 8), 1.33 x 10(- 7), and 2.0 x 10(- 7) mol/L of anti-el2 affinity-purified CChP-IgGs. Taken together, these findings confirmed a competitive interplay of these ligands at the common allosteric site and revealed the novel allosteric nature of the interaction of CChP-IgGs at the M(2)AChRs as a positive cooperativity effect on acetylcholine action.

An update on the management of Chagas cardiomyopathy

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, infects nearly 18 million people in Latin America and mainly affects the heart, causing heart failure, arrhythmias, heart block, thromboembolism, stroke and death. In this review, the clinical diagnosis and management of Chagas cardiomyopathy are discussed. Particular emphasis is placed on the clinical staging of patients and the use of various diagnostic tests that may be useful in individualizing treatment of the two most relevant clinical syndromes, that is, heart failure and arrhythmias. The relevance of specific treatments are discussed, stressing the important role of parasite persistence in disease pathogenesis. We also discuss new therapy modalities that may have a role in the treatment of Chagas cardiomyopathy.

Right ventricular dysfunction is an independent predictor of survival in patients with dilated chronic Chagas' cardiomyopathy

BACKGROUND

Right ventricular (RV) involvement is a typical feature of Chagas' disease. In patients with congestive heart failure of other etiologies, RV dysfunction is a strong indicator of poor prognosis. However, the prognostic value of RV dysfunction in patients with Chagas' cardiomyopathy has not been reported. This study sought to investigate the prognostic value of RV dysfunction, apart from other well established risk factors, in patients with Chagas' cardiomyopathy.

METHODS

The study enrolled 158 patients (99 men; mean age of 48+/-12 years) from a tertiary center for Chagas' disease. Patients were selected if found to have both the diagnosis of Chagas' disease and cardiomyopathy. All patients underwent a comprehensive Doppler echocardiogram and the global RV function was quantitatively assessed using the RV index of myocardial performance (Tei index).

RESULTS

Most of the patients were in NYHA classes I and II (79%). During a mean follow up of 34+/-23 months, 44 patients (28%) died: 24 (55%) patients died of progressive heart failure and 16 (36%) of sudden death. RV Tei index emerged as an independent predictor of survival (hazard ratio 5.75, 95% confidence interval 1.69 to 19.51). Kaplan-Meier survival curves showed a higher cumulative mortality among patients in the highest quartile of RV Tei index, compared with other 3 quartiles (log-rank statistic 21.87, p<0.001). After adjustment for clinical data and LV ejection fraction, RV Tei index in the highest quartile (>0.56) remained a significant predictor of death (hazard ratio 5.29, 95% confidence interval 2.43 to 11.52).

CONCLUSIONS

RV function assessed by the Tei index added significant prognostic information, incremental to the NYHA clinical classification and to the standard echocardiographic evaluation of LV systolic function. A simple measure of a Doppler index, which allows analysis of both systolic and diastolic function of the RV, appears to be a useful non-invasive tool for risk stratification in patients with dilated chronic Chagas' cardiomyopathy.

Echocardiography in Chagas heart disease

BACKGROUND

Chagas heart disease is a frequent cause of morbidity and mortality in Latin America. Echocardiography provides useful diagnostic and prognostic information and is an important tool in the management of patients with Chagas disease.

METHODS AND RESULTS

A search for relevant publications was obtained from MEDLINE, LILACS, and SCIELO sources. Acute Chagas myocarditis is a rare disorder in which pericardial effusion is frequent. Echocardiography may exclude pericardial tamponade in case of heart failure. Chronic Chagas cardiomyopathy evolves for several decades after the infection. Epidemiological history, positive serology, and suggestive clinical and ECG abnormalities establish the diagnosis. About three quarters of chronic Chagas cardiomyopathy subjects remain asymptomatic with normal (indeterminate form) or abnormal ECGs. Early Doppler abnormalities includes prolongation of isovolumic contraction and relaxation times. Systolic function frequently is normal, but dysfunction may be elicited by stress tests. Half or more of symptomatic patients have a left ventricular apical aneurysm and other segmental contractile abnormalities similar to those seen in coronary heart disease. The dilated nonsegmental form is indistinguishable from dilated cardiomyopathy. Results from univariate and multivariate Cox survival analyses indicate that impaired systolic function and increased ventricular dimensions have significant value in predicting cardiac morbidity and mortality. Cardiac ultrasound commonly is used in the follow-up of patients and in the assessment of various therapeutic modalities.

CONCLUSIONS

Echocardiographic and Doppler techniques provide useful structural and functional information in the detection of early myocardial damage, risk assessment of prognosis, disease progression, and management of patients with Chagas disease.

Predictors of Mortality in Chronic Chagas Disease

BACKGROUND

Chagas disease is a major cause of morbidity and mortality in Latin America. Knowledge of the predictors of prognosis can help clinical decision making by identifying patients' level of risk.

METHODS AND RESULTS

We reviewed the published literature on prognostic factors in patients with Chagas disease by performing a PubMed search for articles published in any language between 1985 and February 2006 and hand searches of the reference lists of retrieved articles. Studies were selected if they included patients in the chronic phase of Chagas disease, analyzed a clearly defined outcome (all-cause mortality, sudden cardiac deaths, and/or cardiovascular deaths), and used multivariable regression models of prognosis. From 606 potentially relevant studies, 12 met the inclusion criteria: 8 clinic-based studies including 3928 patients and 4 hospital-based studies including 349 patients. Impaired left ventricular function by echocardiogram or cineventriculogram was found to be the most common and consistent independent predictor of death. New York Heart Association functional class III/IV and cardiomegaly on the chest radiography also were independently associated with higher mortality. More recently, strong evidence was found that nonsustained ventricular tachycardia on 24-hour Holter monitoring indicated an adverse prognosis. The typical ECG abnormalities showed limited additional prognostic value. Other often-mentioned risk factors, advanced age and male sex, showed inconsistent results. A formal meta-analysis was not feasible because of the heterogeneity of published studies and the lack of minimal standards in reporting results.

CONCLUSIONS

A systematic review of published studies indicates that impaired left ventricular function, New York Heart Association class III/IV, cardiomegaly, and nonsustained ventricular tachycardia indicate a poor prognosis in patients with chronic Chagas disease.

Clinical aspects of the Chagas' heart disease

Chagas' heart disease, caused by protozoan Trypanosoma cruzi, is a common cause of cardiomyopathy in the Americas. Transmission of T. cruzi occurs through Reduviids, the kissing bugs. Less common ways of transmission are blood transfusion, congenital transmission, organ transplantation, laboratory accident, breastfeeding, and oral contamination. Infestation results in cardiac dysautonomia, myocardial apoptosis, and myocardial fibrosis. In acute phase, death is mostly caused by myocarditis and in chronic phase, it is mostly by irreversible cardiomyopathy. A majority of the patients with Chagas' disease remain in the latent phase of disease for 10 to 30 years or even for life. Specific anti-Chagas' therapy with trypanocide drugs is useful in acute phase but the management of chronic Chagas' heart disease is mostly empirical. The mortality during the acute phase of cardiac Chagas is around 5%. Five-year mortality of chronic Chagas' disease with cardiac dysfunction is above 50%. The clinical aspects of the Chagas' heart disease are concisely reviewed.

Teste ergométrico e o Holter de 24 horas na detecção de arritmias ventriculares complexas em diferentes estádios da cardiopatia chagásica crônica

Comparou-se o teste ergométrico com Holter de 24 horas na detecção de arritmias ventriculares complexas em diferentes estádios da cardiopatia chagásica crônica. Avaliados 71 pacientes sem outras doenças associadas, idade=51±10,3, metade mulheres. Divididos em quatro grupos conforme o grau de acometimento cardíaco. A estatística esta discriminada no corpo do trabalho. Ao Holter, no grupo IA as arritmias ventriculares complexas foram detectadas em 4,3%, IB em 25%, II em 55% e no grupo III em 90%. Nos grupos II e III não houve diferença entre os exames na detecção de arritmias ventriculares complexas (p=NS). Nos grupos IA e IB, houve uma concordância de 100% no teste ergométrico na não detecção de arritmias ventriculares complexas entre dois observadores. No grupo II, a concordância foi de 70% (kappa=0,368, p=0,003) e de 90% (kappa=0,78, p=0,002) no grupo III. Foi observado diferenças na presença de arritmias ventriculares complexas entre os pacientes dos grupos em fase inicial e avançada da cardiopatia chagásica crônica. Nos pacientes dos grupos II e III não houve diferença entre os dois exames na detecção das arritmias ventriculares complexas. Pacientes dos grupos IA e IB é razoável indicar Holter e/ou o teste ergométrico na ocorrência de progressão da doença.

Value of echocardiography for diagnosis and prognosis of chronic Chagas disease cardiomyopathy without heart failure

OBJECTIVES

To establish the usefulness of echocardiography for the clinical classification of patients with Chagas disease and to determine the predictors of mortality and clinical events.

METHODS

849 patients with chronic Chagas disease with a mean follow up of 9.9 years were studied. On admission, ECG, chest radiograph, and two dimensional echocardiogram were obtained from all patients. Clinical events were defined as new ECG abnormalities, change in clinical status resulting in transfer to another group, and death. Morphologically characterised segmental lesions were also seen in 12 patients on a second harmonic echocardiogram with intravenous contrast agent. Univariate and multivariate analysis for clinical events and mortality were performed.

SETTING

Community of San Martín, Buenos Aires, Argentina.

RESULTS

Change in clinical group (68 of 833 survivors v 15 of 16 who died, p < 0.001), left ventricular systolic dimension (mean (SD) 3.06 (0.72) cm v 4.71 (0.90) cm, p < 0.0001), and ejection fraction (mean (SD) 0.67 (0.11)% v 0.42 (0.17)%, p < 0.0001) were found to be the only predictors of mortality. ECG abnormalities related to the disease (in 220 of 699 patients with no clinical event v 98 of 150 patients with a clinical event, p < 0.0001), left ventricular diastolic dimension (mean (SD) 4.88 (0.54) cm v 5.44 (0.83) cm, p < 0.0001), left ventricular systolic dimension (mean (SD) 2.98 (0.62) cm v 3.64 (1.03) cm, p < 0.0001), and ejection fraction (mean (SD) 0.68 (0.10)% v 0.60 (0.16)%, p < 0.0001) were predictors of clinical events. Segmental lesions were observed in 211 of 849 patients (25%). Segmental lesions were seen in 66 (13%) and systolic dysfunction was seen in four of 505 (0.8%) patients with normal ECG. Significant differences were found between the groups of patients (group 0: reactive serology and normal ECG and chest radiography without cardiac enlargement and no signs of heart failure; group 1: reactive serology and abnormal ECG and chest radiography without cardiac enlargement; group 2: reactive serology and abnormal ECG and chest radiography with cardiac enlargement and no signs of heart failure).

CONCLUSION

Echocardiography was useful both to characterise and to determine the prognosis of patients with chronic Chagas disease without heart failure.

Morphofunctional characteristics of the right ventricle in Chagas' dilated cardiomyopathy

Right ventricular involvement is a typical characteristic of Chagas' disease, and it has been described especially in the early stages of the disease. However, the role of right ventricular dysfunction in cardiac failure due to Chagas' cardiomyopathy has not been well established. Seventy-four patients with positive serology tests for Trypanosoma cruzi and Chagas' dilated cardiomyopathy characterized by left ventricular dilatation and systolic dysfunction were studied. Clinical history, physical exam, ECG, chest X-ray and Doppler echocardiogram with color flow mapping were obtained in all. Mean age was 47.5+/-12.9 and 51 were males (69%). Sixty-five patients (88%) were in NYHA functional classes I and II. Mild systolic dysfunction was present in 35 (47%) while in 18 (24%), dysfunction was moderate and in 21 (28%) it was severe. In 43 patients (58%), only the left ventricle was involved by echocardiographic criteria; the remaining 31 patients (42%) showed biventricular involvement. No patient had isolated involvement of the right ventricle. Greater dilation of the right ventricle was associated with larger diastolic (p<0.002) and systolic (p<0.001) diameters of the left ventricle. Systolic pulmonary artery pressure was obtained non-invasively in 54 patients. Pulmonary hypertension was associated with right ventricular dilation (p<0.005) and with systolic dysfunction of the left ventricle (p<0.001). In this group of patients with Chagas' dilated cardiomyopathy, right ventricular dysfunction was present when there was associated and significant involvement of the left ventricle and with higher levels of pulmonary pressure.

[The prothrombotic state in early stages of chronic chagas' disease]

OBJECTIVE

This study was designed to explore the presence of a prothrombotic state in the early stages of chronic Chagas' disease by evaluating serum markers of thrombosis and fibrinolysis.

PATIENTS AND METHOD

Forty-two patients with chronic Chagas' disease (12 men and 30 women, 32.5 6.7 years) were compared with 21 healthy volunteers (10 men and 11 women, 24.2 5.6 years). The markers of thrombotic activation used were fragment 1 + 2, ATM complex, PDF/pdf, D-dimer, and beta-thromboglobulin. Fibrinolysis was evaluated before and after venous occlusion, together with euglobulin lysis time, t-PA, and PAI-1 titers.

RESULTS

The markers of thrombotic state were significantly higher in patients with chronic Chagas' disease than in controls: F1 + 2 (p < 0.0001), ATM (p < 0.0001), PDF/pdf (p < 0.05), and D dimer (p < 0.05). There was no significant difference in beta-thromboglobulin (p = 0.06). Euglobulin lysis time, a global fibrinolytic marker, differed significantly (p < 0.0001) between patients with Chagas' disease and healthy volunteers. However, the more specific fibrinolytic markers t-PA and PAI-1 did not differ significantly between the two study groups.

CONCLUSIONS

Although there were no significant differences in fibrinolytic markers between patients with chronic Chagas' disease and healthy volunteers, the significant increase in thrombosis markers (F1 + 2, ATM complex, PDF/pdf, and D dimer) suggests the presence of a prothrombotic state in the early stages of chronic Chagas' disease.

[Emergencies in patients with Chagas' disease in Buenos Aires city, Argentina]

The objective of this work was to evaluate the most frequent causes of emergency in patients with Chagas disease. Between January 1998-January 1999, individuals with Chagas disease inside the shock-room of Santojanni Hospital in Buenos Aires city, were included in a prospective study. For the statistical analysis, X test with Yates correction has been used. From a total of 1.680 patients entered, there were 95 (6%) with reactive serology for Chagas disease. In 31 individuals the enter cause was syncope, in 28 cardiac insufficiency, in 18 acute coronary events, in 5 stroke, in 3 acute edema of hypertensive lung and in 2 acute encephalitis associated to AIDS. In conclusion, significant association has been observed between: 1) presence of cardiopathy and hospitalization, 2) cardiac insufficiency, syncope, acute encephalitis and mortality, 3) cardiopathy development and mortality and 4) origin place and mortality.