Inspiratory muscle endurance is similarly reduced in the early and late stages of chronic Chagas heart disease

OBJECTIVE

Inspiratory muscle strength (IMS) appears to be reduced in subjects with chronic Chagas heart disease (CHD), especially in the presence of heart failure (HF). However, only one study about IMS and inspiratory muscle endurance (IME) in those with CHD without heart failure is available. This study aimed to compare IMS and IME in subjects with CHD in the presence and absence of HF.

METHODS

This is a cross-sectional study in which 30 CHD adult patients were divided into CHD-CC group (initial phase of CHD, without HF; n = 15) and CHD-HF group (advanced phase of CHD, with HF; n = 15). We assessed IMS by maximum inspiratory pressure (MIP) and IME by incremental (Pthmax) and constant load (TLim) tests. Reduced IMS and IME were considered by predicted MIP values <70% and Pthmax/MIP <75%, respectively.

RESULTS

Inspiratory muscle weakness (IMW) was more frequent in CHD-HF than in CHD-CC (46.7% vs. 13.3%; p = 0.05), and both groups had high frequencies of reduced IME (93.3% CHD-CC vs. 100.0% CHD-HF; p = 0.95). Age-adjusted logistic regression analysis using HF as a dependent variable showed that HF was associated with an increased chance of IMW compared with the CHD-CC group (OR = 7.47; p = 0.03; 95% CI 1.20-46.19).

CONCLUSION

This study suggests that, in patients with CHD, HF is associated with IMW, and that reduction of IME is already present in the initial phase, similar to the advanced phase with HF.

Cardiac Abnormalities in a Predictive Mouse Model of Chagas Disease

Chronic Chagas cardiomyopathy (CCC) results from infection with the protozoan parasite Trypanosoma cruzi and is a prevalent cause of heart disease in endemic countries. We previously found that cardiac fibrosis can vary widely in C3H/HeN mice chronically infected with T. cruzi JR strain, mirroring the spectrum of heart disease in humans. In this study, we examined functional cardiac abnormalities in this host:parasite combination to determine its potential as an experimental model for CCC. We utilised electrocardiography (ECG) to monitor T. cruzi-infected mice and determine whether ECG markers could be correlated with cardiac function abnormalities. We found that the C3H/HeN:JR combination frequently displayed early onset CCC indicators, such as sinus bradycardia and right bundle branch block, as well as prolonged PQ, PR, RR, ST, and QT intervals in the acute stage. Our model exhibited high levels of cardiac inflammation and enhanced iNOS expression in the acute stage, but denervation did not appear to have a role in pathology. These results demonstrate the potential of the C3H/HeN:JR host:parasite combination as a model for CCC that could be used for screening new compounds targeted at cardiac remodelling and for examining the potential of antiparasitic drugs to prevent or alleviate CCC development and progression.

Coronary microvascular dysfunction due to Chagas Disease: where are we now?

INTRODUCTION

Myocardial ischemia is common in patients with chronic Chagas cardiomyopathy (CCC), but only recently clinical and experimental studies highlighted the involvement of this abnormality as contributing to progression of myocardial damage.

AREAS COVERED

Despite absence of obstructive epicardial coronary artery disease at angiography, and limited evidence of abnormal flow regulation at the macrovascular level, remarkable functional and structural microvascular abnormalities are consistently reported by independent investigations CCC. These derangements occur early and contribute to myocardial dysfunction. Recent research focused on reversing microvascular dysfunction as a target to positively impact the course of CCC. We conducted an extensive review of the scientific literature, aiming to summarize the role of coronary dysfunction causing myocardial ischemia in CCC, with a focus on implications for clinical management of individuals affected by this disease.

EXPERT OPINION

Preclinical studies showed a clear correlation between perfusion defects and inflammation in viable but impaired dysfunctional myocardium. These findings provided further insight into the CCC complex pathophysiology and support the role of very few recent therapeutic interventions aiming to relieve myocardial ischemia. Further research is warranted to assess the efficacy of new interventions addressing reversal of microvascular ischemia and inflammation modulation and halting ventricular dysfunction progression in CCC.

Chronic Trypanosoma cruzi infection activates the TWEAK/Fn14 axis in cardiac myocytes and fibroblasts driving structural and functional changes that affect the heart

Sustained interaction between the cytokine tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its functional receptor, fibroblast growth factor-inducible 14 (Fn14), has been linked to cardiovascular disorders. Chagas cardiomyopathy, elicited by Trypanosoma cruzi infection, is associated with chronic inflammation, fibrosis and hypertrophy. This study aimed to explore the involvement of the TWEAK/Fn 14 axis in development of Chagas heart disease. Parasite infection in vitro triggered Fn14 overexpression in atrial HL-1 myocytes and cardiac MCF fibroblasts. Fn14 levels were also increased in heart tissue from C57BL/6 mice at 130 days post-infection, particularly in myocytes and fibroblasts. Concurrently, TWEAK expression in circulating monocytes from this group was higher than that determined in uninfected controls. TWEAK/Fn14 interaction was functional in myocytes and fibroblasts isolated from infected hearts, leading to TNF receptor-associated factor 2 (TRAF2)-mediated activation of nuclear factor kappa B (NFκB) signaling. Ex vivo stimulation of both cell types with recombinant TWEAK for 24 h boosted the NFκB-regulated production of proinflammatory/profibrotic mediators (IL-1β, IL-6, TNF-α, IL-8, CCL2, CCL5, MMP-2, MMP-9, ICAM-1, E-selectin) involved in chronic T. cruzi cardiomyopathy. We further evaluated the therapeutic potential of the soluble decoy receptor Fn14-Fc to interfere with TWEAK/Fn14-dependent pathogenic activity. Fn14-Fc treatment of chronically infected mice was effective in neutralizing the ligand and reverting electrocardiographic abnormalities, maladaptive inflammation, adverse remodeling and hypertrophy in myocardium. Altogether, these findings suggest that sustained TWEAK/Fn14 induction by persistent T. cruzi infection is implicated in cardiopathogenesis and make TWEAK/Fn14 axis a promising target for the treatment of chronic Chagas heart disease.

Case report: diagnosis of chronic Chagas cardiomyopathy using a multimodality imaging approach

Background

In the USA, ∼300 000 people are affected by Chagas heart disease, a growing, but commonly overlooked, public health issue. Chagas as a potential aetiology of dilated cardiomyopathy remains under-recognized. We present a case where multimodality imaging was essential in the diagnosis and management of Chagas heart disease.

Case summary

A 54-year-old man, originally from Mexico, presented to the emergency department with chest pain and recurrent syncopal episodes, found to be in haemodynamically unstable ventricular tachycardia (VT) requiring urgent cardioversion. Urgent coronary angiography revealed no obstructive disease. A transthoracic echocardiogram revealed moderately reduced left ventricular systolic function (left ventricular ejection fraction 35-40%) with apical akinesis and an aneurysm of the apical septum. Cardiac magnetic resonance (CMR) confirmed a prominent apical aneurysm with dyskinesis of the apical septum, with the evidence of transmural myocardial late gadolinium enhancement of the entire left ventricular apex and a small apical thrombus. Serologic testing was positive for Trypanosoma cruzi IgG antibody, which was confirmed on repeat testing at the Centers for Disease Control and Prevention. Patient underwent VT ablation and was discharged on guideline-directed medical therapy including a regimen of anticoagulation, beta-blocker, and angiotensin-converting enzyme inhibitor therapies. He has had no subsequent syncope or VT.

Discussion

Chagas heart disease remains under-recognized and under-diagnosed despite the growing burden of T. cruzi infection in the USA. Suspicion for Chagas heart disease should be considered in patients presenting with heart failure symptoms and ventricular arrhythmias with the right corresponding history and imaging findings on echocardiogram and CMR.

Recent trends in hospital admissions and outcomes of cardiac Chagas disease in the United States

Background:

Chagas disease (CD), caused by Trypanosoma cruzi, has been increasingly encountered as a cause of cardiovascular disease in the United States. We aimed to examine trends of hospital admissions and cardiovascular outcomes of cardiac CD (CCD).

Methods:

Search of 2003-2011 Nationwide Inpatient Sample database identified 949 (age 57±16 years, 51% male, 72.5% Hispanic) admissions for CCD.

Results:

A significant increase in the number of admissions for CCD was noted during the study period (OR=1.054; 95% CI=1.028-1.081; P< 0.0001); 72% were admitted to Southern and Western hospitals. Comorbidities included hypertension (40%), coronary artery disease (28%), hyperlipidemia (26%), tobacco use (12%), diabetes (9%), heart failure (5%) and obesity (2.2%). Cardiac abnormalities noted during hospitalization included atrial fibrillation (27%), ventricular tachycardia (23%), sinoatrial node dysfunction (5%), complete heart block (4%), valvular heart disease (6%)] and left ventricular aneurysms (5%). In-hospital mortality was 3.2%. Other major adverse events included cardiogenic shock in 54 (5.7%), cardiac arrest in 30 (3.2%), acute heart failure in 88 (9.3%), use of mechanical circulatory support in 29 (3.1%), and acute stroke in 34 (3.5%). Overall, 63% suffered at least one adverse event. Temporary (2%) and permanent (3.5%) pacemakers, implantable cardioverter defibrillators (10%), and cardiac transplant (2.1%) were needed for in-hospital management.

Conclusions:

Despite the remaining concerns about lack of awareness of CCD in the US, an increasing number of hospital admissions were reported from 2003-2011. Serious cardiovascular abnormalities were highly prevalent in these patients and were frequently associated with fatal and nonfatal complications.

Melatonin decreases circulating Trypanosoma cruzi load with no effect on tissue parasite replication

Cardiac damage during the acute phase of Chagas disease (CD) is associated with an increase in pro-inflammatory markers and oxidative stress. Melatonin (MEL) has emerged as a promising therapy for CD due to its antioxidant and immunomodulatory properties; however, the protective action of MEL in the cardiac tissue, as well as its direct action on the parasite cycle, is not fully understood. We investigated the effects of MEL on heart parasitism in mice infected with Trypanosoma cruzi and also its effects on the parasitic proliferation in vitro. Our in vivo study showed that MEL reduced circulating parasitemia load, but did not control tissue (heart, liver, and spleen) parasitism in mice. MEL did not prevent the redox imbalance in the left ventricle of infected mice. Our in vitro findings showed that MEL did not inhibit parasites replication within cells, but rather increased their release from cells. MEL did not control parasitism load in the heart or prevent the cardiac redox imbalance induced by acute T. cruzi infection. The hormone controlled the circulating parasitic load, but within cells MEL accelerated parasitic release, a response that can be harmful.

Exercise training improves microvascular function in patients with Chagas heart disease: Data from the PEACH study

BACKGROUND

Chagas heart disease (CHD) impairs the systemic microvascular function. We investigated the effects of exercise training on cutaneous microvascular function among patients with CHD.

METHODS

Patients from the PEACH study were randomly assigned to a supervised exercise training 3 times/week for 6 months (Trained; n = 10) or a control group (Untrained; n = 8). Both groups underwent evaluation of microvascular function before, and at 3- and 6-months of follow-up. Cutaneous vascular conductance (CVC) was assessed in the skin of the forearm using laser speckle contrast imaging coupled with iontophoresis of acetylcholine (ACh), sodium nitroprusside (SNP) and during post-occlusive reactive hyperemia (PORH).

RESULTS

At 3-months of follow-up, no difference was detected between groups in CVC responses to ACh (p = 0.50), SNP (p = 0.26) and HRPO (p = 0.65). However, at 6-months of follow-up, trained vs. untrained patients improved CVC induced by SNP-iontophoresis (0.19 ± 0.10 vs. 0.14 ± 0.15 APU.mmHg^-1; p = 0.05) and PORH (0.63 ± 0.15 vs. 0.48 ± 0.18 APU.mmHg^-1; p = 0.05). CVC response to ACh-iontophoresis was similar between groups (0.19 ± 0.11 vs. 0.22 ± 0.17 APU.mmHg^-1; p = 0.38).

CONCLUSION

Exercise training performed during 6 months improved the cutaneous microvascular function of CHD patients. Further studies evaluating the mechanism involved in this response are warranted.

Thrombospondin-1 Plays an Essential Role in Yes-Associated Protein Nuclear Translocation during the Early Phase of Trypanosoma cruzi Infection in Heart Endothelial Cells

The protozoan parasite Trypanosoma cruzi is the causative agent of Chagas disease. This neglected tropical disease causes severe morbidity and mortality in endemic regions. About 30% of T. cruzi infected individuals will present with cardiac complications. Invasive trypomastigotes released from infected cells can be carried in the vascular endothelial system to infect neighboring and distant cells. During the process of cellular infection, the parasite induces host cells, to increase the levels of host thrombospondin-1 (TSP-1), to facilitate the process of infection. TSP-1 plays important roles in the functioning of vascular cells, including vascular endothelial cells with important implications in cardiovascular health. Many signal transduction pathways, including the yes-associated protein 1 (YAP)/transcriptional coactivator, with PDZ-binding motif (TAZ) signaling, which are upstream of TSP-1, have been linked to the pathophysiology of heart damage. The molecular mechanisms by which T. cruzi signals, and eventually infects, heart endothelial cells remain unknown. To evaluate the importance of TSP-1 expression in heart endothelial cells during the process of T. cruzi infection, we exposed heart endothelial cells prepared from Wild Type and TSP-1 Knockout mouse to invasive T. cruzi trypomastigotes at multiple time points, and evaluated changes in the hippo signaling cascade using immunoblotting and immunofluorescence assays. We found that the parasite turned off the hippo signaling pathway in TSP-1KO heart endothelial cells. The levels of SAV1 and MOB1A increased to a maximum of 2.70 ± 0.23 and 5.74 ± 1.45-fold at 3 and 6 h, respectively, in TSP-1KO mouse heart endothelial cells (MHEC), compared to WT MHEC, following a parasite challenge. This was accompanied by a significant continuous increase in the nuclear translocation of downstream effector molecule YAP, to a maximum mean nuclear fluorescence intensity of 10.14 ± 0.40 at 6 h, compared to wild type cells. Furthermore, we found that increased nuclear translocated YAP significantly colocalized with the transcription co-activator molecule pan-TEAD, with a maximum Pearson's correlation coefficient of 0.51 ± 0.06 at 6 h, compared to YAP-Pan-TEAD colocalization in the WT MHEC, which decreased significantly, with a minimum Pearson's correlation coefficient of 0.30 ± 0.01 at 6 h. Our data indicate that, during the early phase of infection, upregulated TSP-1 is essential for the regulation of the hippo signaling pathway. These studies advance our understanding of the molecular interactions occurring between heart endothelial cells and T. cruzi, in the presence and absence of TSP-1, providing insights into processes linked to parasite dissemination and pathogenesis.

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.

Systematic Review and Meta-Analysis of Clinical Outcome After Implantable Cardioverter-Defibrillator Therapy in Patients With Chagas Heart Disease

OBJECTIVES

The goal of this analysis was to pool data from published studies on outcomes after implantable cardioverter-defibrillator (ICD) therapy in patients with Chagas heart disease (CHD).

BACKGROUND

CHD is characterized by a high burden of ventricular arrhythmias and an increased risk of sudden cardiac death. The indications for ICD are not well established.

METHODS

An extensive literature search without language restrictions was performed to identify all studies on ICD therapy in patients with CHD. A random effects model was used to calculate percentages and 95% confidence intervals (CIs).

RESULTS

Of 397 articles screened, 13 studies (all observational) were included. There were 1,041 patients (mean age at implantation 57 ± 11 years; 64% men), most of whom (92%) received an ICD for secondary prevention. Antiarrhythmic medication consisted of amiodarone (79%) and beta-blockers (44%). Overall, the annual all-cause mortality rate was 9.0% (95% CI: 6.9 to 11.7) in 2.8 ± 1.9 years of follow-up, and the annual sudden cardiac death rate was 2.0% (95% CI: 1.3 to 3.3) in 2.6 ± 1.9 years. In addition, 24.8% (95% CI: 15.7 to 37.0) of patients received 1 or more appropriate interventions (shocks or antitachycardia pacing), 4.7% (95% CI: 3.2 to 6.9) received inappropriate shocks, and 9.1% (95% CI: 5.5 to 14.7) had electric storms annually.

CONCLUSIONS

In patients with an ICD, annual all-cause mortality rate was 9%. Appropriate ICD interventions and electric storms were frequent, occurring at a rate of 25% and 9% per year, respectively. Inappropriate ICD shocks were not infrequent (5% per year). The benefits and risks of ICD therapy in patients with CHD should be carefully weighed until data from better studies become available.

Dysregulation of insulin levels in Chagas heart disease is associated with altered adipocytokine levels

Metabolic, inflammatory, and autonomic nervous system (ANS) dysfunction are present in patients with heart failure. However, whether these changes are due to left ventricular dysfunction or heart failure etiology is unknown. We evaluated metabolism and inflammatory activity in patients with idiopathic dilated cardiomyopathy (IDC) and Chagas cardiomyopathy (CHG) and their correlation with the ANS. Forty-six patients were divided into 3 groups: IDC, CHG, and control. We evaluated adiponectin, leptin, insulin, interleukin-6, and tumor necrosis factor-alpha. ANS were analyzed by heart rate variability in time and frequency domains on a 24-hour Holter monitor. Levels of glucose, cholesterol, leptin, and adiponectin did not show differences between groups. Insulin levels were lower in CHG group (5.4 ± 3.3 μU/mL) when compared with control (8.0 ± 4.9 μU/mL) and IDC (9.9 ± 5.0 μU/mL) groups (p = 0.007). Insulin was positively associated with LFr/HFr ratio (r = 0.562; p = 0.029) and with the LFr component (r = 0.562; p = 0.029) and negatively associated with adiponectin (r = -0.603; p = 0.017) in CHG group. The addition of an adiponectin unit reduced average insulin by 0.332 μg/mL. Insulin levels were decreased in the CHG group when compared with the IDC group and were associated with ANS indexes and adiponectin levels.

The prognostic value of health-related quality of life in patients with Chagas heart disease

PURPOSE

To verify the prognostic value of health-related quality of life (HRQoL) and the differences in HRQoL and clinical variables between groups of Chagas heart disease (CHD) patients with and without cardiovascular adverse events.

METHODS

Seventy-five CHD patients were evaluated by echocardiography, maximal exercise testing, and Short-form of Health Survey (SF-36) Questionnaire. Patients were followed during 6 years. In the statistical analysis, uni- and multivariate Cox regression were performed to verify the accuracy of the HRQoL in predicting cardiovascular events.

RESULTS

After the follow-up period (41 ± 12 months), 20 patients (27%) had adverse events. Those with poor outcome had lower left ventricular ejection fraction (LVEF) (p = 0.002), higher left ventricular end-diastolic diameter (LVDd) (p = 0.019), and worse scores in general health perceptions (p = 0.047), social role functioning (p = 0.026), and mental component summary (p = 0.043) of SF-36. Patients with lower LVEF (p = 0.003), higher LVDd (p = 0.022), worse HRQoL in the general heath perceptions domain (p = 0.022), and mental component summary (p = 0.031) were associated with worse prognosis. In the multivariate Cox regression, LVEF (HR 0.94, 95% CI from 0.90 to 0.98, p = 0.007) and mental component summary (HR 0.98, 95% CI from 0.94 to 1.00, p = 0.047) remained as independent predictors of adverse events in CHD patients.

CONCLUSION

The assessment of HRQoL, especially the mental component, should be taken into account to provide an accurate prognosis in addition to other well-established predictors of poor outcomes in CHD patients.

Is endothelial microvascular function equally impaired among patients with chronic Chagas and ischemic cardiomyopathy?

BACKGROUND

Chronic Chagas cardiomyopathy (CCC) and cardiomyopathies due to other etiologies involve differences in pathophysiological pathways that are still unclear. Systemic microvascular abnormalities are associated with the pathogenesis of ischemic heart disease. However, systemic microvascular endothelial function in CCC remains to be elucidated. Thus, we compared the microvascular endothelial function of patients presenting with CCC to those with ischemic cardiomyopathy disease.

METHODS

Microvascular reactivity was assessed in 21 patients with cardiomyopathy secondary to Chagas disease, 21 patients with cardiomyopathy secondary to ischemic disease and 21 healthy controls. Microvascular blood flow was assessed in the skin of the forearm using laser speckle contrast imaging coupled with iontophoresis of acetylcholine (ACh).

RESULTS

Peak increase in forearm blood flow with ACh iontophoresis in relation to baseline was greater in healthy controls than in patients with heart disease (controls: 162.7 ± 58.4% vs. ischemic heart disease: 74.1 ± 48.3% and Chagas: 85.1 ± 68.1%; p < 0.0001). Patients with Chagas and ischemic cardiomyopathy presented similar ACh-induced changes from baseline in skin blood flow (p = 0.55).

CONCLUSION

Endothelial microvascular function was equally impaired among patients with CCC and ischemic cardiomyopathy.

Dysautonomy in different death risk groups (Rassi score) in patients with Chagas heart disease

BACKGROUND

It has been difficult to prove that "catecholamine-induced cardiomyopathy" contributes to the mechanism of sudden cardiac death in Chagas heart disease. Also, it is almost impossible to rule out the possibility that it is not involved in the process. More importantly, the vagal-cholinergic pathway in the ventricle plays a direct role in the prevention of the initiation of complex ventricular arrhythmias, including nonsustained ventricular tachycardia, ventricular fibrillation responsible for sudden death.

OBJECTIVE

To determine frequency of parasympathetic autonomic indices among the different groups of risk of cardiovascular death when stratified by Rassi score.

METHODS

Patients with Chagas heart disease were selected and divided into three risk groups by Rassi score. A fourth group, non-Chagas group, was of similar age and gender. All were subjected to analysis of heart rate variability during controlled breathing (RSA) and tilt table passive test (tilt test). High frequency and low frequency/high frequency ratio were calculated and presented by box-plot. Also, t-test was used to compare the two groups.

RESULTS

It was observed that the parasympathetic and sympathetic component were affected, when the risk group increased the response was worsened to the stimulus (RSA or Tilt). Also, the low-risk group was jeopardized, when compared to the non-Chagas group.

CONCLUSION

The loss of parasympathetic modulation was present in all Rassi risk groups, including the low risk, indicating that a morphological change of the myocardium represents a detectable neurofunctional change.

Effect of physical exercise training in patients with Chagas heart disease: study protocol for a randomized controlled trial (PEACH study)

Background

The effects of exercise training on Chagas heart disease are still unclear. This study aimed to evaluate the effect of exercise training over functional capacity, cardiac function, quality of life, and biomarkers in Chagas heart disease.

Methods

The PEACH study is a superiority randomized clinical trial which will include subjects who meet the following criteria: Chagas heart disease with a left ventricular ejection fraction below 45 % with or without heart failure symptoms; clinical stability in the last 3 months; adherence to clinical treatment; and age above 18 years. The exclusion criteria are: pregnancy; neuromuscular limitations; smoking; evidence of non-chagasic heart disease; systemic conditions that limit exercise practice or cardiopulmonary exercise test; unavailability to attend the center three times a week during the intervention period; and practitioners of regular exercise. The intervention group will perform an exercise training intervention three times per week during 6 months and will be compared to the control group without exercise. Both groups will undergo the same monthly pharmaceutical and nutritional counseling as well as standard medical treatment according to the Brazilian consensus on Chagas disease. The primary outcome is functional capacity based on peak exercise oxygen consumption during cardiopulmonary exercise testing. Secondary outcomes are: cardiac function; body composition; muscle respiratory strength; microvascular reactivity; cardiac rhythm abnormalities; autonomic function; biochemical; oxidative stress and inflammatory biomarkers; and quality of life. Subjects will be evaluated at baseline, and at 3 and 6 months after randomization. Thirty patients will be randomly assigned into exercise or control groups at a ratio of 1:1.

Discussion

Findings of the present study will be useful to determine if physical exercise programs should be included as an important additional therapy in the treatment of patients with Chagas heart disease.

Trial registration

ClinicalTrials.gov ID: NCT02517632 (registered on 6 August 2015).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1553-4) contains supplementary material, which is available to authorized users.