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Background: The influence of exercise on cardiac metabolic response in patients with Chagas disease is incompletely understood., Methods and Results: Changes in cardiac energetic metabolism were investigated in Chagas disease patients before and during isometric handgrip exercise with (31)P magnetic resonance spectroscopy (MRS). Twenty-eight patients (10 with systolic dysfunction: group I; 10 with normal systolic function and electrocardiogram (ECG) abnormalities: group II; and 8 asymptomatic without ECG abnormalities: group III) and 8 healthy control subjects (group C) were evaluated by electrocardiogram, echocardiogram, functional tests for coronary artery disease, and image-selected localized cardiac (31)P-MRS. The myocardial phosphocreatine to [β-phosphate]adenosine triphosphate ratio (PCr/β-ATP) was measured at rest and during isometric handgrip exercise. Exercise testing or 99mTc-sestamibi scintigraphy were negative for myocardial ischemia in all individuals. At rest, cardiac PCr/β-ATP was decreased in all Chagas groups (1.23 ± 0.37) versus group C (1.88 ± 0.08; P < .001) and was lower in group I (0.89 ± 0.24) versus groups II (1.44 ± 0.23) and III (1.40 ± 0.37; P < .001). There was no stress-induced change in cardiac PCr/β-ATP (1.88 ± 0.08 at rest vs 1.89 ± 0.08 during exercise; P = NS) in group C. Mean cardiac PCr/β-ATP was 0.89 ± 0.24 and 0.56 ± 0.21 at rest and during exercise, respectively, in group I (37% decrease; P < .001). In group II, PCr/β-ATP was 1.44 ± 0.23 at rest and 0.97 ± 0.37 during exercise (33% decrease; P < .001). In group III, PCr/β-ATP was 1.40 ± 0.37 at rest and 0.60 ± 0.19 during exercise (57% decrease; P < .001)., Conclusions: Myocardial high-energy phosphates are reduced at rest in Chagas heart disease patients, and the reduction is greater in patients with left ventricular dysfunction. Regardless of left ventricular function, Chagas patients exhibit an exercise-induced decline in cardiac high-energy phosphates consistent with myocardial ischemia, suggesting the possibility that this metabolic approach may offer a tool to probe new interventions in Chagas disease patients., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: The hallmark of Chagas disease (CD) is multifocal myocarditis and extensive fibrosis. We investigated the potential effect of colchicine on myocardial remodeling in experimental CD., Methods and Results: One hundred Syrian hamsters were randomly divided into noninfected untreated control (CG), noninfected control treated with colchicine (COLG 0.4 mg kg(-1) d(-1) by gavage), infected (IG), and infected treated with colchicine (ICOLG, 0.4 mg kg(-1) d(-1)) groups. The interstitial collagen volume fraction (ICVF) was evaluated by videomorphometry with picrosirius red staining. The gelatinolytic activities of matrix metalloproteinase (MMP) 2 were examined with the use of zymography. Myocarditis was described according to the Dallas criteria. Statistical comparisons were performed with parametric analysis of variance and Tukey test. ICVF (%) accumulation was attenuated in infected colchicine-treated animals in the left (CG 0.81 ± 0.13, COLG 0.85 ± 0.13, IG: 1.35 ± 0.31,* ICOLG 1.06 ± 0.19; *P < .05 compared with ICOLG) and right ventricles (CG 1.4 ± 0.36, COLG 1.26 ± 0.14, IG 1.97 ± 0.058,* ICOLG: 1.52 ± 0.23; *P < .05 compared with ICOLG). A significant increase in MMP-2 enzymatic activity (UA) was observed in ICOLG (17,432.8*) compared with GC (3731.6), COLG (2,792.6), and IG (4,286.3; *P < .001). In IG, 66% of animals had myocarditis compared with only 49% in ICOLG., Conclusions: Colchicine had a protective effect on myocardium, indicated by decreased interstitial myocardial fibrosis, increased intensity of MMP-2, and attenuated myocardial inflammation., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Systemic sclerosis (SSc) is a disease characterized by the fibrosis of the skin and internal organs. The nature and functional significance of myocardial damage is controversial. Systematic endomyocardial biopsy in this disease has not yet been performed., Methods: The hypothesis that increased myocardial fibrous tissue deposition occurs in patients with systemic sclerosis with no signs or symptoms of heart failure and normal left systolic ventricle function was tested in 16 SSc patients and 10 controls. Endomyocardial biopsy specimens were obtained from the right ventricular septum in SSc patients. Myocardial specimens were obtained from the same area in controls. Masson's trichrome staining was used for collagen fiber identification. Interstitial (ICVF) and perivascular collagen volume fraction (PCVF) was quantified by videomorphometry. There was a significant increase in the ICVF in patients with SSc compared with the controls, in spite of normal systolic left ventricular function. However, it was not observed in the PCVF., Conclusions: It is possible to identify cardiac remodeling, characterized by myocardial fibrosis deposits, particularly within the interstitium in SSc patients before the any signs or symptoms of heart failure appear.

Background: Chagas' disease is a known dilated form of cardiomyopathy. However, a great number of patients, although showing electrocardiographic (ECG) well-recognized changes, maintain normal ventricular chamber dimensions and are asymptomatic. The aim of the present study was to objectively characterize functional capacity in asymptomatic patients with Chagas' disease and normal left ventricular function., Methods and Results: Eighteen asymptomatic male patients with Chagas' disease, aged 33+/-6 years, were selected for the study. All showed ECG changes typical of the disease, as well as left ventricular fractional shortening (LVFS) greater than 0.30 on M-mode 2-dimensionally guided echocardiography. Twenty sedentary normal male patients, aged 29+/-6 years, served as controls. Both groups were submitted to ergoespirometry testing for assessment of exercise functional capacity. Patients with Chagas' disease, when compared with controls, showed lower (P < .001) maximal O2 consumption (VO2max, 24.3+/-4.2 v 37.0+/-5.4 mL x kg(-1) x min(-1) respectively); O2 pulse rate (PO2max, 10.5+/-1.4 v 15.1+/-2.5 mL/beat, respectively); maximal ventilation (VEmax, 50.1+/-13.5 v 113.0+/-17.6 L x min(-1), respectively); anaerobic threshold of maximal O2 consumption (VO2-AT, 15.8+/-3.6 v 24.6+/-4.7 mL x kg(-1) x min(-1), respectively); and maximal heart rate (HRmax, 154+/-21 v 186+/-7 beat x min(-1), respectively)., Conclusions: Asymptomatic patients with Chagas' disease, although presenting normal left ventricular systolic function at rest, display a substantial impairment of exercise functional capacity.