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Although it is known that obesity, diabetes, and Kawasaki's disease play important roles in systemic inflammation and in the development of both endothelial dysfunction and cardiomyopathy, there is a lack of data regarding the endothelial function of pre-pubertal children suffering from cardiomyopathy. In this study, we performed a systematic review of the literature on pre-pubertal children at risk of developing cardiomyopathy to assess the endothelial function of pre-pubertal children at risk of developing cardiomyopathy. We searched the published literature indexed in PubMed, Bireme and SciELO using the keywords 'endothelial', 'children', 'pediatric' and 'infant' and then compiled a systematic review. The end points were age, the pubertal stage, sex differences, the method used for the endothelial evaluation and the endothelial values themselves. No studies on children with cardiomyopathy were found. Only 11 papers were selected for our complete analysis, where these included reports on the flow-mediated percentage dilatation, the values of which were 9.80±1.80, 5.90±1.29, 4.50±0.70, and 7.10±1.27 for healthy, obese, diabetic and pre-pubertal children with Kawasaki's disease, respectively. There was no significant difference in the dilatation, independent of the endothelium, either among the groups or between the genders for both of the measurements in children; similar results have been found in adolescents and adults. The endothelial function in cardiomyopathic children remains unclear because of the lack of data; nevertheless, the known dysfunctions in children with obesity, type 1 diabetes and Kawasaki's disease may influence the severity of the cardiovascular symptoms, the prognosis, and the mortality rate. The results of this study encourage future research into the consequences of endothelial dysfunction in pre-pubertal children.

Objective: We sought to evaluate the neurohormonal activity in heart transplant recipients and compare it with that in heart failure patients and healthy subjects during rest and just after a 6-minute walking test., Introduction: Despite the improvements in quality of life and survival provided by heart transplantation, the neurohormonal profile is poorly described., Methods: Twenty heart transplantation (18 men, 49+/-11 years and 8.5+/-3.3 years after transplantation), 11 heart failure (8 men, 43+/-10 years), and 7 healthy subjects (5 men 39+/-8 years) were included in this study. Blood samples were collected immediately before and during the last minute of the exercise., Results: During rest, patients' norepinephrine plasma level (659+/-225 pg/mL) was higher in heart transplant recipients (463+/-167 pg/mL) and healthy subjects (512+/-132), p<0.05. Heart transplant recipient's norepinephrine plasma level was not different than that of healthy subjects. Just after the 6-minute walking test, the heart transplant recipient's norepinephrine plasma level (1248+/-692 pg/mL) was not different from that of heart failure patients (1174+/-653 pg/mL). Both these groups had a higher level than healthy subjects had (545+/-95 pg/mL), p<0.05., Conclusion: Neurohormonal activity remains increased after the 6-minute walking test after heart transplantation.

Background: The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients either on non-optimized or off beta-blocker therapy is known to be unreliable. The aim of this study was to evaluate the relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients receiving optimized and non-optimized beta-blocker treatment during a treadmill cardiopulmonary exercise test., Methods: A total of 27 sedentary heart failure patients (86% male, 50+/-12 years) on optimized beta-blocker therapy with a left ventricle ejection fraction of 33+/-8% and 35 sedentary non-optimized heart failure patients (75% male, 47+/-10 years) with a left ventricle ejection fraction of 30+/-10% underwent the treadmill cardiopulmonary exercise test (Naughton protocol). Resting and peak effort values of both the percentage of oxygen consumption reserve and percentage of heart rate reserve were, by definition, 0 and 100, respectively., Results: The heart rate slope for the non-optimized group was derived from the points 0.949+/-0.088 (0 intercept) and 1.055+/-0.128 (1 intercept), p<0.0001. The heart rate slope for the optimized group was derived from the points 1.026+/-0.108 (0 intercept) and 1.012+/-0.108 (1 intercept), p=0.47. Regression linear plots for the heart rate slope for each patient in the non-optimized and optimized groups revealed a slope of 0.986 (almost perfect) for the optimized group, but the regression analysis for the non-optimized group was 0.030 (far from perfect, which occurs at 1)., Conclusion: The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in patients on optimized beta-blocker therapy was reliable, but this relationship was unreliable in non-optimized heart failure patients.

Background: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients., Aim: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test., Methods: Twenty-five heart failure patients (49+/-11 years, 76% male), with an average LVEF of 30+/-7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months., Results: Basal heart rate was lower in heart failure patients (57+/-3 bpm) compared to controls (89+/-14 bpm; p<0.0001). Similarly, the peak heart rate (% maximum predicted for age) was lower in HF patients (65.4+/-11.1%) compared to controls (98.6+/-2.2; p<0.0001). Maximum respiratory exchange ratio did not differ between the groups (1.2+/-0.5 for controls and 1.15+/-1 for heart failure patients; p=0.42). All controls reached the maximum heart rate for their age, while no patients in the heart failure group reached the maximum. Moreover, the % increase of heart rate from rest to peak exercise between heart failure (48+/-9%) and control (53+/-8%) was not different (p=0.157)., Conclusion: No patient in the heart failure group reached the maximum heart rate for their age during a treadmill cardiopulmonary exercise test, despite the fact that the percentage increase of heart rate was similar to sedentary normal subjects. A heart rate increase in optimized beta-blocked heart failure patients during cardiopulmonary exercise test over 65% of the maximum age-adjusted value should be considered an effort near the maximum. This information may be useful in rehabilitation programs and ischemic tests, although further studies are required.

Introduction: The six-minute walk test (6WT) has been proposed to be a submaximal test, but could actually demand a high level of exercise intensity from the patient, expressed by a respiratory quotient >1.0, following the guideline recommendations. Standardizing the 6WT using the Borg scale was proposed to make sure that all patients undergo a submaximal walking test., Purpose: To test the reproducibility of the six-minute treadmill cardiopulmonary walk test (6CWT) using the Borg scale and to make sure that all patients undergo a submaximal test., Methods: Twenty-three male heart failure patients (50+/-9 years) were included; these patients had both ischemic (5) and non-ischemic (18) heart failure with a left ventricle ejection fraction of 23+/-7%, were diagnosed as functional class NYHA II-III and were undergoing optimized drug therapy. Patients were guided to walk at a pace between "relatively easy and slightly tiring" (11 and 13 on Borg scale). The 6CWT using the Borg scale was performed two times on a treadmill with zero inclination and patient control of speed with an interval of 24 hours. During the sixth minute, we analyzed ventilation (VE, L/min), respiratory quotient, Oxygen consumption (VO2, ml/kg/min), VE/VCO2 slope, heart rate (HR, bpm), systolic blood pressure (SBP, mmHg), diastolic (DBP, mmHg) blood pressure and distance., Results: The intraclass correlation coefficients at the sixth minute were: HR (r i=0.96, p<0.0001), VE (r i=0.84, p<0.0001), SBP (r i=0.72, p=0.001), distance (r i=0.88, p<0.0001), VO2 (r i=0.92, p<0.0001), SlopeVE/VCO2 (r i=0.86, p<0.0001) and RQ<1 (r i=0.6, p=0.004)., Conclusion: Using the 6CWT with the Borg scale was reproducible, and it seems to be an appropriate method to evaluate the functional capacity of heart failure patients while making sure that they undergo a submaximal walking test.