Corrigendum: Home-based exercise program in the indeterminate form of Chagas disease (PEDI-CHAGAS study): a study protocol for a randomized clinical trial.

[This corrects the article DOI: 10.3389/fmed.2022.1087188.].

The association of exercise test variables with long-term mortality in patients with chronic Chagas disease.

Background: The identification of variables obtained in the exercise test (ET) associated with increased risk of death is clinically relevant and would provide additional information for the management of Chagas disease (CD). The objective of the present study was to evaluate the association of ET variables with mortality in patients with chronic CD. Methods: This retrospective longitudinal observational study included 232 patients (median age 46.0 years; 50% women) with CD that were followed at the Evandro Chagas National Institute of Infectious Diseases (Rio de Janeiro, Brazil) and performed an ET between 1989 and 2000. The outcome of interest was all-cause mortality. Results: There were 103 deaths (44.4%) during a median follow-up of 21.5 years (IQR 25-75% 8.0-27.8), resulting in 24.5 per 1,000 patients/year incidence rate. The ET variables associated with mortality after adjustments for potential confounders were increased maximal (HR 1.02; 95% CI 1.00-1.03 per mmHg) and change (HR 1.03; 95% CI 1.01-1.06 per mmHg) of diastolic blood pressure (DBP) during ET, ventricular tachycardia at rest (HR 3.95; 95% CI 1.14-13.74), during exercise (HR 2.73; 95% CI 1.44-5.20), and recovery (HR 2.60; 95% CI 1.14-5.91), and premature ventricular complexes during recovery (HR 2.06; 1.33-3.21). Conclusion: Our findings suggest that ET provides important prognostic value for mortality risk assessment in patients with CD, with hemodynamic (increased DBP during exercise) and electrocardiographic (presence of ventricular arrhythmias) variables independently associated with an increased mortality risk in patients with CD. The identification of individuals at higher mortality risk can facilitate the development of intervention strategies (e.g., close follow-up) that may potentially have an impact on the longevity of patients with CD.

Home-based exercise program in the indeterminate form of Chagas disease (PEDI-CHAGAS study): A study protocol for a randomized clinical trial.

Background: Chagas disease (CD) is a neglected endemic disease with worldwide impact due to migration. Approximately 50-70% of individuals in the chronic phase of CD present the indeterminate form, characterized by parasitological and/or serological evidence of Trypanosoma cruzi infection, but without clinical signs and symptoms. Subclinical abnormalities have been reported in indeterminate form of CD, including pro-inflammatory states and alterations in cardiac function, biomarkers and autonomic modulation. Moreover, individuals with CD are usually impacted on their personal and professional life, making social insertion difficult and impacting their mental health and quality of life (QoL). Physical exercise has been acknowledged as an important strategy to prevent and control numerous chronic-degenerative diseases, but unexplored in individuals with the indeterminate form of CD. The PEDI-CHAGAS study (which stands for "Home-Based Exercise Program in the Indeterminate Form of Chagas Disease" in Portuguese) aims to evaluate the effects of a home-based exercise program on physical and mental health outcomes in individuals with indeterminate form of CD. Methods and design: The PEDI-CHAGAS is a two-arm (exercise and control) phase 3 superiority randomized clinical trial including patients with indeterminate form of CD. The exclusion criteria are <18 years old, evidence of non-Chagasic cardiomyopathy, musculoskeletal or cognitive limitations that preclude the realization of exercise protocol, clinical contraindication for regular exercise, and regular physical exercise (≥1 × per week). Participants will be assessed at baseline, and after three and 6 months of follow-up. The primary outcome will be QoL. Secondary outcomes will include blood pressure, physical fitness components, nutritional status, fatigability, autonomic modulation, cardiac morphology and function, low back pain, depression and anxiety, stress, sleep quality, medication use and adherence, and biochemical, inflammatory and cardiac biomarkers. Participants in the intervention group will undergo a home-based exercise program whilst those in the control group will receive only general information regarding the benefits of physical activity. Both groups will receive the same general nutritional counseling consisting of general orientations about healthy diets. Conclusion: The findings from the present study may support public health intervention strategies to improve physical and mental health parameters to be implemented more effectively in this population. Clinical trial registration: [https://ensaiosclinicos.gov.br/rg/RBR-10yxgcr9/], identifier [U1111-1263-0153].

Physiological responses in different intensities of resistance exercise - Critical load and the effects of aging process.

Aim was to identify critical load (CL) in young and elderly apparently healthy male cohorts. To contrast the metabolic, cardiovascular and perceptual responses on CL according to age. We evaluated 12 young (23 ± 3 years) and 10 elderly (70 ± 2 years) apparently healthy active males, who underwent: (1) 1 repetition maximum (1RM) test on a 45° Leg Press; (2) on different days, three high-intensity resistance exercise constant load tests (60%, 75% and 90% 1RM) until fatigue (Tlim). Absolute values of both the CL asymptote and curvature constant (kg) were significantly lower in elderly subjects (P < 0.05). In contrast, elderly subjects demonstrated a significantly higher number of repetitions at CL when compared with young subjects (P < 0.05). As expected, oxygen uptake (VO2) and heart rate (HR) during maximal aerobic exercise testing were significantly reduced in older subjects. However, percent-predicted aerobic capacity were higher in older subjects (P < 0.05). In addition, blood lactate ([La-]) corrected to Tlim and rating of perceived exertion values were greater in younger subjects at all intensities (P < 0.05). These findings, despite reduced force production in older subjects, endurance-related parameters are well preserved according to age-adjusted percent-predicted values in apparently healthy males.

Early exercise-based rehabilitation improves health-related quality of life and functional capacity after acute myocardial infarction: a randomized controlled trial.

BACKGROUND: The purpose of this study was to evaluate the influence of an early cardiac rehabilitation (CR) program on health-related quality of life (HRQL) and functional capacity in patients who recently experienced an acute myocardial infarction (AMI). This program was initiated in the inpatient setting and was followed by an unsupervised outpatient intervention. METHODS: After the same inpatient care plan, low-risk patients who experienced an AMI were randomized into 2 groups: (1) a control group (CG) (n = 43) entailing usual care and (2) an intervention group (IG) (n = 45) entailing outpatient (unsupervised) CR primarily centered on a progressive walking program. Initially, all patients underwent a supervised exercise program with early mobilization beginning 12 hours after an AMI. On hospital discharge, all patients were classified according to cardiovascular risk. Quality of life was evaluated by the MacNew Heart Disease HRQL questionnaire 30 days after discharge. Functional capacity was determined by a 6-minute walk test (6MWT) distance on the day of inpatient discharge as well as 30 days afterward. RESULTS: The HRQL global score was higher in the IG compared with the CG 30 days after discharge (P < 0.001); physical and emotional domain scores were both significantly higher in the IG (P < 0.001). Furthermore, the IG showed a greater 6MWT distance compared with the CG (P < 0.001). CONCLUSIONS: A CR program based on early progressive exercises, initiated by supervised inpatient training and followed by an unsupervised outpatient program, improved HRQL and functional capacity in patients at low cardiovascular risk who recently experienced an AMI.

Impact of CPAP on physical exercise tolerance and sympathetic-vagal balance in patients with chronic heart failure.

BACKGROUND: Chronic heart failure (CHF) leads to exercise intolerance. However, non-invasive ventilation is able to improve functional capacity of patients with CHF. OBJECTIVES: The aim of this study was to evaluate the effectiveness of continuous positive airway pressure (CPAP) on physical exercise tolerance and heart rate variability (HRV) in patients with CHF. Method : Seven men with CHF (62 ± 8 years) and left ventricle ejection fraction of 41 ± 8% were submitted to an incremental symptom-limited exercise test (IT) on the cicloergometer. On separate days, patients were randomized to perform four constant work rate exercise tests to maximal tolerance with and without CPAP (5 cmH2O) in the following conditions: i) at 50% of peak work rate of IT; and ii) at 75% of peak work rate of IT. At rest and during these conditions, instantaneous heart rate (HR) was recorded using a cardiofrequencimeter and HRV was analyzed in time domain (SDNN and RMSSD indexes). For statistical procedures, Wilcoxon test or Kruskall-Wallis test with Dunn's post-hoc were used accordingly. In addition, categorical variables were analysed through Fischer's test (p<0.05). RESULTS: There were significant improvements in exercise tolerance at 75% of peak work rate of IT with CPAP (405 ± 52 vs. 438 ± 58 s). RMSSD indexes were lower during exercise tests compared to CPAP at rest and with 50% of peak work rate of IT. CONCLUSION: These data suggest that CPAP appears to be a useful strategy to improve functional capacity in patients with CHF. However, the positive impact of CPAP did not generate significant changes in the HRV during physical exercises.

Impact of CPAP on physical exercise tolerance and sympathetic-vagal balance in patients with chronic heart failure / Impacto da CPAP sobre a tolerância ao exercício físico e a modulação simpatovagal de pacientes com insuficiência cardíaca crônica

Background: Chronic heart failure (CHF) leads to exercise intolerance. However, non-invasive ventilation is able to improve functional capacity of patients with CHF. Objectives: The aim of this study was to evaluate the effectiveness of continuous positive airway pressure (CPAP) on physical exercise tolerance and heart rate variability (HRV) in patients with CHF. Method : Seven men with CHF (62±8 years) and left ventricle ejection fraction of 41±8% were submitted to an incremental symptom-limited exercise test (IT) on the cicloergometer. On separate days, patients were randomized to perform four constant work rate exercise tests to maximal tolerance with and without CPAP (5 cmH2O) in the following conditions: i) at 50% of peak work rate of IT; and ii) at 75% of peak work rate of IT. At rest and during these conditions, instantaneous heart rate (HR) was recorded using a cardiofrequencimeter and HRV was analyzed in time domain (SDNN and RMSSD indexes). For statistical procedures, Wilcoxon test or Kruskall-Wallis test with Dunn's post-hoc were used accordingly. In addition, categorical variables were analysed through Fischer's test (p<0.05). Results: There were significant improvements in exercise tolerance at 75% of peak work rate of IT with CPAP (405±52 vs. 438±58 s). RMSSD indexes were lower during exercise tests compared to CPAP at rest and with 50% of peak work rate of IT. Conclusion: These data suggest that CPAP appears to be a useful strategy to improve functional capacity in patients with CHF. However, the positive impact of CPAP did not generate significant changes in the HRV during physical exercises. .

Contextualização: A insuficiência cardíaca (IC) crônica cursa com intolerância ao exercício físico. A ventilação não invasiva (VNI) tem se mostrado benéfica para a melhora da performance desses pacientes. Objetivos: Avaliar a eficiência da pressão positiva contínua nas vias aéreas (CPAP) sobre a tolerância ao exercício físico e a variabilidade da frequência cardíaca (VFC) de pacientes com IC crônica. Método: Sete homens com IC crônica (62±8 anos) e fração de ejeção do ventrículo esquerdo de 41±8% foram submetidos ao teste incremental (TI) sintoma-limitado em cicloergômetro. Posteriormente, foram aleatorizados para a realização de exercícios físicos de carga constante até a tolerância máxima com e sem CPAP (5 cmH2O) nas condições: i) 50% da carga pico do TI e ii) 75% da carga pico do TI. Em repouso e durante os testes, a frequência cardíaca (FC) instantânea foi obtida pelo cardiofrequencímetro, e a VFC foi analisada no domínio do tempo. A análise estatística foi realizada pelos testes de Wilcoxon ou Kruskall-Wallis com post-hoc de Dunn e as variáveis categóricas, pelo teste de Fischer (p<0,05). Resultados: Durante a CPAP, houve aumento significativo no tempo de exercício físico (405±52 vs. 438±58 s) e da FC pico (97±3 vs. 105±2 bpm) somente na intensidade de 75%. Em relação à VFC, observou-se que o RMSSD foi significativamente menor em exercício físico quando comparado ao repouso com CPAP na intensidade 50%. Conclusão: Em conclusão, a CPAP com 5 cmH20 mostrou-se um útil na melhora da capacidade funcional dos pacientes estudados com pouco impacto sobre a VFC. .

Determination of anaerobic threshold through heart rate and near infrared spectroscopy in elderly healthy men.

BACKGROUND: Aging leads to low functional capacity and this can be reversed by safe and adequate exercise prescription. OBJECTIVE: The aim of this study was to identify the anaerobic threshold (AT) obtained from the V-slope method as well as visual inspection of oxyhemoglobin ( O2Hb) and deoxyhemoglobin (HHb) curves and compare findings with the heteroscedastic (HS) method applied to carbon dioxide production ( CO2), heart rate (HR), and HHb data in healthy elderly men. A secondary aim was to assess the degree of agreement between methods for AT determination. METHOD: Fourteen healthy men (61.4±6.3 years) underwent cardiopulmonary exercise testing (CPX) on a cycle ergometer until physical exhaustion. Biological signals collected during CPX included: ventilatory and metabolic variables; spectroscopy quasi-infrared rays - NIRS; and HR through a cardio-frequency meter. RESULTS: We observed temporal equivalence and similar values of power (W), absolute oxygen consumption (O2 - mL/min), relative O2 ( mL.Kg - 1.min -1), and HR at AT by the detection methods performed. In addition, by the Bland-Altman plot, HR confirmed good agreement between the methods with biases between -1.3 and 3.5 beats per minute. CONCLUSIONS: (i) all detection methods were sensitive in identifying AT, including the HS applied to HR and (ii) the methods showed a good correlation in the identification of AT. Thus, these results support HR as valid and readily available parameter in determining AT in healthy elderly men.

Determination of anaerobic threshold through heart rate and near infrared spectroscopy in elderly healthy men

BACKGROUND: Aging leads to low functional capacity and this can be reversed by safe and adequate exercise prescription. OBJECTIVE: The aim of this study was to identify the anaerobic threshold (AT) obtained from the V-slope method as well as visual inspection of oxyhemoglobin ( O2Hb) and deoxyhemoglobin (HHb) curves and compare findings with the heteroscedastic (HS) method applied to carbon dioxide production ( CO2), heart rate (HR), and HHb data in healthy elderly men. A secondary aim was to assess the degree of agreement between methods for AT determination. METHOD: Fourteen healthy men (61.4±6.3 years) underwent cardiopulmonary exercise testing (CPX) on a cycle ergometer until physical exhaustion. Biological signals collected during CPX included: ventilatory and metabolic variables; spectroscopy quasi-infrared rays - NIRS; and HR through a cardio-frequency meter. RESULTS: We observed temporal equivalence and similar values of power (W), absolute oxygen consumption (O2 - mL/min), relative O2 ( mL.Kg - 1.min -1), and HR at AT by the detection methods performed. In addition, by the Bland-Altman plot, HR confirmed good agreement between the methods with biases between -1.3 and 3.5 beats per minute. CONCLUSIONS: (i) all detection methods were sensitive in identifying AT, including the HS applied to HR and (ii) the methods showed a good correlation in the identification of AT. Thus, these results support HR as valid and readily available parameter in determining AT in healthy elderly men. .

Autonomic control of heart rate in patients with chronic cardiorespiratory disease and in healthy participants at rest and during a respiratory sinus arrhythmia maneuver.

OBJECTIVE: To evaluate the autonomic modulation of heart rate (HR) at rest in the supine position and during a respiratory sinus arrhythmia maneuver (M-RSA) among participants with chronic obstructive pulmonary disease (COPD) or with chronic heart failure (CHF). METHODS: Twenty-eight men were divided into three groups: ten with COPD, aged 69+/-9 years; nine with CHF, aged 62+/-8 years; and nine healthy participants aged 64+/-5 years (controls). At rest, the R-R interval of the electrocardiographic signal was obtained in the following situations: 1) 15 min in the supine position; and 2) 4 min during M-RSA in the supine position. The data were analyzed in the time domain (RMSSD and SDNN indices) and the frequency domain (LFab and HFab). During M-RSA, the expiratory/inspiratory ratio (E/I) and the inspiratory/expiratory difference (IE) were calculated. RESULTS: The main findings showed that the CHF patients presented lower RMSSD (12.2+/-2.6 vs. 20.4+/-6.5), LFab (99.2+/-72.7 vs. 305.3+/-208.9) and HFab (53.4+/-29.9 vs. 178.9+/-113.1), compared with the controls. The LFab band was significantly lower in the COPD group than in the controls (133.8+/-145.5 vs. 305.3+/-208.9). Additionally, both CHF patients and COPD patients showed lower E/I ratios (1.1+/-0.06 vs. 1.2+/-0.1 and 1.1+/-0.03 vs. 1.2+/-0.1) and IE values (7.0+/-3.5 vs. 12.7+/-0.1 and 4.9+/-1.6 vs. 12.7+/-0.1), respectively, compared with the controls during M-RSA. CONCLUSION: The results from this study suggest that both COPD and CHF have a negative impact on the autonomic control of heart rate. Article registered on the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number: ACTRN12609000467235.

Controle autonômico da frequência cardíaca de pacientes com doenças cardiorrespiratórias crônicas e indivíduos saudáveis em repouso e durante a manobra de acentuação da arritmia sinusal respiratória / Autonomic control of heart rate in patients with chronic cardiorespiratory disease and in healthy participants at rest and during a respiratory sinus arrhythmia maneuver

OBJETIVO: Avaliar a modulação autonômica da frequência cardíaca (FC) em repouso, na postura supina e durante a manobra de acentuação da arritmia sinusal respiratória (M-ASR) de pacientes com doença pulmonar obstrutiva crônica (DPOC) ou com insuficiência cardíaca crônica (ICC). MÉTODOS: Vinte e oito homens foram subdivididos em três grupos: 10 com DPOC (GD) e 69±9 anos; 9 com ICC (GI) e 62±8 anos; e 9 saudáveis (GC) com 64±5 anos. Em repouso, os intervalos R-R a partir do sinal eletrocardiográfico foram obtidos nas seguintes situações: 1) 15 minutos na posição supina e 2) 4 minutos durante M-ASR na posição supina. Os dados foram analisados nos domínios do tempo (índices RMSSD e SDNN) e da frequência. Durante M-ASR, foram calculadas a razão expiração/inspiração (E/I) e a diferença inspiração/expiração (∆IE). RESULTADOS: Os principais achados mostraram que os pacientes com ICC apresentaram menores valores de RMSSD (12,2±2,6 vs 20,4±6,5), BFab (99,2±72,7 vs 305,3±208,9) e AFun (53,4±29,9 vs 178,9±113,1) quando comparados ao controle. Além disso, a banda de BFab foi significantemente reduzida no grupo DPOC quando comparado ao controle (133,8±145,5 vs 305,3±208,9). Adicionalmente, pacientes com ICC e DPOC mostraram menor razão E/I (1,1±0,06 vs 1,2±0,1 e 1,1±0,03 vs 1,2±0,1) e ∆IE (7,0±3,5 vs 12,7±0,1 e 4,9±1,6 vs 12,7±0,1), respectivamente, comparados ao GC durante a M-ASR. CONCLUSÃO: Os resultados deste estudo sugerem que tanto a DPOC como a ICC produzem impacto negativo sobre o controle autonômico da FC.

OBJECTIVE: To evaluate the autonomic modulation of heart rate (HR) at rest in the supine position and during a respiratory sinus arrhythmia maneuver (M-RSA) among participants with chronic obstructive pulmonary disease (COPD) or with chronic heart failure (CHF). METHODS: Twenty-eight men were divided into three groups: ten with COPD, aged 69±9 years; nine with CHF, aged 62±8 years; and nine healthy participants aged 64±5 years (controls). At rest, the R-R interval of the electrocardiographic signal was obtained in the following situations: 1) 15 min in the supine position; and 2) 4 min during M-RSA in the supine position. The data were analyzed in the time domain (RMSSD and SDNN indices) and the frequency domain (LFab and HFab). During M-RSA, the expiratory/inspiratory ratio (E/I) and the inspiratory/expiratory difference (∆IE) were calculated. RESULTS: The main findings showed that the CHF patients presented lower RMSSD (12.2±2.6 vs. 20.4±6.5), LFab (99.2±72.7 vs. 305.3±208.9) and HFab (53.4±29.9 vs. 178.9±113.1), compared with the controls. The LFab band was significantly lower in the COPD group than in the controls (133.8±145.5 vs. 305.3±208.9). Additionally, both CHF patients and COPD patients showed lower E/I ratios (1.1±0.06 vs. 1.2±0.1 and 1.1±0.03 vs. 1.2±0.1) and ∆IE values (7.0±3.5 vs. 12.7±0.1 and 4.9±1.6 vs. 12.7±0.1), respectively, compared with the controls during M-RSA. CONCLUSION: The results from this study suggest that both COPD and CHF have a negative impact on the autonomic control of heart rate.

Acute effects of different levels of continuous positive airway pressure on cardiac autonomic modulation in chronic heart failure and chronic obstructive pulmonary disease.

INTRODUCTION: Non-invasive ventilation may improve autonomic modulation and ventilatory parameters in severely disabled patients. The aim of the present study was to evaluate the physiological influence of acute treatment with different levels of continuous positive airway pressure (CPAP) on the autonomic balance of heart and respiratory responses in patients with stable chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). MATERIALS AND METHODS: A COPD group (n = 10), CHF group (n = 8) and healthy subjects (n = 10) were evaluated. The participants were randomized to receive three different levels of CPAP on the same day: sham ventilation (Sham), 5 cmH(2)0 (CPAP5) and 10 cmH(2)0 (CPAP10) for 10 min. Respiratory rate, end tidal carbon dioxide (E(T)CO(2)), peripheral oxygen saturation (SpO(2)), heart rate (HR), blood pressure and heart rate variability in the time and frequency domains were measured during spontaneous breathing and under the sham, CPAP5 and CPAP10 conditions. RESULTS: All groups experienced a reduction in E(T)CO(2) values during treatment with CPAP (p < 0.05). CPAP increased SpO(2) and HR in the COPD group (p < 0.05). The COPD group also had lower RMSSD values during treatment with different levels of CPAP when compared to the control group (p < 0.05). In the CHF group, CPAP5 and CPAP10 increased the SDNN value (p < 0.05). CPAP10 reduced the SDNN value in the COPD group (p < 0.05). CONCLUSION: The findings suggest that CPAP may cause improvements in the neural control of heart rate in patients with stable COPD and CHF. For each patient, the "best CPAP level" should be defined as the best respiratory response and autonomic balance.