Effectiveness of inspiratory muscle training associated with a cardiac rehabilitation program on sympathetic activity and functional capacity in patients with heart failure: a study protocol for a randomized controlled trial.

BACKGROUND: Individuals affected by heart failure (HF) may present fatigue, dyspnea, respiratory muscle weakness, and sympathetic activity hyperstimulation of the myocardium, among other symptoms. Conducting cardiac rehabilitation (CR) programs can be associated with inspiratory muscle training. The aim of this study was to evaluate the efficacy of inspiratory muscular training (IMT) associated with a CR program on modulating myocardial sympathetic activity and maximal functional capacity, submaximal functional capacity, thickness, and mobility of the diaphragm muscle in patients with HF. METHODS: We will conduct a clinical, controlled, randomized, double-blind trial that will include sedentary men and women who are 21-60 years old and who have diagnosed systolic HF and a left ventricular ejection fraction of less than 45%. Participants will be randomly assigned to one of two groups: experimental and control. The control group will follow the conventional CR protocol, and the experimental group will follow the conventional CR protocol associated with IMT 7 days a week. The two proposed exercise protocols will have a frequency of three times a week for a period of 12 weeks. The sympathetic innervation of the cardiac muscle, the maximum and submaximal functional capacity, diaphragm mobility and thickness, and the quality of life of the participants will be evaluated before and after the intervention protocol. DISCUSSION: This clinical trial will be the first study to investigate the additional effects of IMT on CR in sympathetic hyperstimulation in the myocardium. The results of this study will contribute to developing therapeutic strategies collaborating to elucidate whether the association of IMT with CR can induce clinical benefits for patients with HF. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02600000. Registered November 9, 2015. Retrospectively registered.

Influence of High-Intensity Interval Training Versus Continuous Training on Functional Capacity in Individuals With Heart Failure: A SYSTEMATIC REVIEW AND META-ANALYSIS.

INTRODUCTION: Cardiac rehabilitation programs reduce the risk of death and acute events related to the disease through the association of various modalities of exercise. When implemented in high-intensity interval training (HIIT) programs, it may allow for gradual adaptation of the skeletal muscles to greater exercise intensities. The present systematic review aimed to determine whether HIIT promoted a greater increase in exercise tolerance in comparison with continuous aerobic training in individuals with heart failure. METHODS: A systematic search for articles indexed in the PubMed/MEDLINE, LILACS, SciELO, PEDro, Scopus, and Web of Science databases was carried out. The descriptors used for the search followed the description of the MeSH/DeCS terms with no language or year of publication restrictions. When possible, a meta-analysis was performed and the quality of the evidence was evaluated using the GRADE scale. RESULTS: The broad search strategy resulted in 5258 titles, and a total of 7 articles were included in the qualitative synthesis. A low quality of evidence was observed demonstrating that interval training is superior to continuous aerobic training for improving peak oxygen uptake, which reflects an increase in functional capacity of these individuals and moderate quality of evidence regarding improved quality of life and left ventricular ejection fraction. CONCLUSION: High-intensity interval training and continuous training provide benefits for patients, however, the quality of evidence still does not allow us to indicate whether there is a superiority of HIIT over conventional continuous exercise training using the variables analyzed.

The Impact of Bariatric Surgery on Cardiopulmonary Function: Analyzing VO2 Recovery Kinetics.

PURPOSE: To assess cardiopulmonary capacity, autonomic heart function, and oxygen recovery kinetics during exercise testing before and after bariatric surgery. METHODS: This is a prospective cohort study. Symptom-limited cardiopulmonary exercise testing was performed with 24 patients, 1 week before and 4 months after bariatric surgery. The main variables were maximum oxygen uptake (VO2 max), the time elapsed until the appearance of the first ventilatory threshold (TLV1), and VO2 oxygen kinetics during recovery with a 50% reduction in peak oxygen uptake in the recovery period after exercise (50%VO2RP). RESULTS: The study demonstrated that the peak VO2\kg increased significantly after bariatric surgery. When analyzed without adjusting for weight, the peak VO2 paradoxically and significantly decreased after the surgical procedure (p = 0.007). The exercise time until the anaerobic threshold was longer after surgical procedure than before it (p = 0.001). Regarding post-exercise oxygen recovery kinetics, there was a faster reduction in the peak oxygen uptake after bariatric surgery than before the procedure (p < 0.001). CONCLUSIONS: There was an obvious cardiac autonomic improvement after surgery. Despite the improvement in exercise tolerance, patients undergoing bariatric surgery had lower maximum oxygen consumption in the analysis not corrected for body weight. The mean VO2RP before bariatric surgery was 141 s and was 111 s after the surgical procedure (p < 0.001). These results suggest an improvement in the recovery kinetics of oxygen consumption, a novel index of cardiac reserve capacity, on patients undergoing bariatric surgery.

Noninvasive Ventilation Before Maximum Exercise Test Increases Exercise Tolerance in Subjects With Heart Failure: A Crossover Study.

OBJECTIVE: To evaluate the effect of noninvasive ventilation (NIV) on exercise performance in individuals with heart failure (HF). DESIGN: Crossover, blind, randomized controlled trial with allocation concealment. SETTING: University-based research laboratory. PARTICIPANTS: Participants (N=24) with New York Heart Association class II and III left heart failure and with a mean age of 51.8±10.2 years (women: n=8; men: n=16). INTERVENTIONS: Ventilatory support attached to the face of the individual via a facemask prior to cardiopulmonary exercise test (CPET) was administered at 2 pressure levels for 30 minutes. Inspiratory pressure of 15cmH2O and expiratory pressure of 5cmH2O were applied. MAIN OUTCOME MEASURES: Maximal oxygen uptake, maximum heart rate, variation between the initial and maximum heart rates, CPET duration, and recovery time oxygen consumption. RESULTS: Differences were observed in maximal oxygen consumption (nonintervention phase: 18.3±4.4mL·kg-1·min-1 vs NIV phase: 20.6±4.9mL·kg-1·min-1, P=.01), heart rate (nonintervention phase: 127.3±20.9 beats per minute vs NIV phase: 134.7±19.5 beats per minute, P=.04), and heart rate variation (nonintervention phase: 63.3%±19.3% vs NIV phase: 69.7%±16.6%, P=.02). Moreover, differences in cardiopulmonary exercise time (nonintervention phase: 7.4±1.5min vs NIV phase: 8.3±1.7min, P=.01) and oxygen consumption recovery time (nonintervention phase: 2.8±1.0min vs NIV phase: 2.4±0.8min, P=.01) were observed. CONCLUSIONS: NIV elicited beneficial effects in the HF population that included increased exercise tolerance, recovery time optimization, and improved chronotropic and respiratory reserves.