A Pilot Study of Inspiratory Muscle Training to Improve Exercise Capacity in Patients with Fontan Physiology.

While the Fontan procedure has improved life expectancy, patients with single ventricle physiology have impaired exercise capacity due to limited increase in pulmonary blood flow during activity. Enhancing the "thoracic pump" using inspiratory muscle training (IMT) may ameliorate this impairment. Adult nonsmokers with Fontan physiology were recruited through Boston Children's Hospital's outpatient clinic. Participants underwent cardiopulmonary exercise testing and pulmonary function testing, followed by 12 weeks of IMT and then repeat testing. The primary endpoint was change in % predicted peak oxygen consumption (VO2). Secondary endpoints were changes in other exercise metrics. Eleven patients (6 male) were enrolled. Median ages at time of enrollment and Fontan completion were 28.8 years (25.7, 45.5) and 7.8 years (3.9, 16.5), respectively. Average baseline maximal inspiratory pressure (MIP) was normal; only 2 patients had MIP <70% predicted. Peak work rate improved significantly from baseline after 12 weeks of IMT (116.5 ± 45.0 to 126.8 ± 47.0 W, P = 0.019). Peak VO2 tended to improve (baseline 68.1 ± 14.3, change + 5.3 ± 9.6% predicted, P = 0.12), as did VE/VCO2 slope (34.1 ± 6.7 to 31.4 ± 3.6, P = 0.12). There was no change in peak tidal volume or MIP. In a small cohort of Fontan patients with mostly normal MIP, IMT was associated with significant improvement in peak work rate and a trend toward higher peak VO2 and improved ventilatory efficiency. Larger studies are needed to determine if this reflects true lack of effect or whether this pilot study was underpowered for effect size, and whether IMT is more narrowly useful for patients with impaired MIP.

Wu FM ，Opotowsky AR ，Denhoff ER ，Gongwer R ，Gurvitz MZ ，Landzberg MJ ，Shafer KM ，Valente AM ，Uluer AZ ，Rhodes J ... -  《-》

Inspiratory Muscle Training Is Associated With Improved Inspiratory Muscle Strength, Resting Cardiac Output, and the Ventilatory Efficiency of Exercise in Patients With a Fontan Circulation.

Patients with a Fontan circulation have reduced exercise capacity and respiratory muscle strength. Inspiratory muscle training (IMT) improves exercise capacity and quality of life in adults with heart failure. We assessed whether 6 weeks of a home-based program of IMT improves inspiratory muscle strength and the ventilatory efficiency of exercise in adolescent patients with a Fontan circulation. Twenty-three adolescent participants (aged 16±2 years) with a Fontan circulation underwent 6 weeks of IMT for 30 minutes daily. Respiratory muscle strength (maximal inspiratory pressure and expiratory pressure), lung function, and exercise capacity (cardiopulmonary exercise testing) were assessed. Fourteen of 23 participants also underwent exercise cardiac magnetic resonance imaging to examine the effects of IMT on cardiac output and systemic and pulmonary blood flow. Six weeks of IMT improved maximal inspiratory pressure by 36±24 cm H2O (61±46%) with no change in maximal expiratory pressure. Ventilatory efficiency of exercise improved after 6 weeks of IMT (from 34.2±7.8 to 32.2±5.6, P=0.04). In those who underwent exercise cardiac magnetic resonance imaging, IMT increased resting cardiac output (from 4.2±1.2 to 4.5±1.0 L/min, P=0.03) and ejection fraction (from 50.1±4.3 to 52.8±6.1%, P=0.03). Six weeks of IMT is associated with improved inspiratory muscle strength, ventilatory efficiency of exercise, and resting cardiac output in young Fontan patients. IMT may be a simple beneficial addition to the current management of Fontan patients, potentially reducing exercise intolerance and long-term morbidity and mortality.

Laohachai K ，Winlaw D ，Selvadurai H ，Gnanappa GK ，d'Udekem Y ，Celermajer D ，Ayer J ... -  《Journal of the American Heart Association》

Aerobic exercise and inspiratory muscle training increase functional capacity in patients with univentricular physiology after Fontan operation: A randomized controlled trial.

The effect of exercise training and its mechanisms on the functional capacity improvement in Fontan patients (FP) are virtually unknown. This trial evaluated four-month aerobic exercise training and inspiratory muscle training on functional capacity, pulmonary function, and autonomic control in patients after Fontan operation. A randomized controlled clinical trial with 42 FP aged 12 to 30 years and, at least, five years of Fontan completion. Twenty-seven were referred to a four-months supervised and personalized aerobic exercise training (AET) or an inspiratory muscle training (IMT). A group of non-exercise (NET) was used as control. The effects of the exercise training in peak VO2; pulmonary volumes and capacities, maximal inspiratory pressure (MIP); muscle sympathetic nerve activity (MSNA); forearm blood flow (FBF); handgrip strength and cross-sectional area of the thigh were analyzed. The AET decreased MSNA (p = 0.042), increased FBF (p = 0.012) and handgrip strength (p = 0.017). No significant changes in autonomic control were found in IMT and NET groups. Both AET and IMT increased peak VO2, but the increase was higher in the AET group compared to IMT (23% vs. 9%). No difference was found in the NET group. IMT group showed a 58% increase in MIP (p = 0.008) in forced vital capacity (p = 0.011) and forced expiratory volume in the first second (p = 0.011). No difference in pulmonary function was found in the AET group. Both aerobic exercise and inspiratory muscle training improved functional capacity. The AET group developed autonomic control, and handgrip strength, and the IMT increased inspiratory muscle strength and spirometry. ClinicalTrials.gov Identifier: NCT02283255.

Turquetto ALR ，Dos Santos MR ，Agostinho DR ，Sayegh ALC ，de Souza FR ，Amato LP ，Barnabe MSR ，de Oliveira PA ，Liberato G ，Binotto MA ，Negrão CE ，Canêo LF ，Trindade E ，Jatene FB ，Jatene MB ... -  《-》

Effects of inspiratory muscle training in patients with heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF) is remarkably common in elderly people with highly prevalent comorbid conditions. Despite its increasing in prevalence, there is no evidence-based effective therapy for HFpEF. We sought to evaluate whether inspiratory muscle training (IMT) improves exercise capacity, as well as left ventricular diastolic function, biomarker profile and quality of life (QoL) in patients with advanced HFpEF and nonreduced maximal inspiratory pressure (MIP). A total of 26 patients with HFpEF (median (interquartile range) age, peak exercise oxygen uptake (peak VO2) and left ventricular ejection fraction of 73 years (66-76), 10 ml/min/kg (7.6-10.5) and 72% (65-77), respectively) were randomized to receive a 12-week programme of IMT plus standard care vs. standard care alone. The primary endpoint of the study was evaluated by positive changes in cardiopulmonary exercise parameters and distance walked in 6 minutes (6MWT). Secondary endpoints were changes in QoL, echocardiogram parameters of diastolic function, and prognostic biomarkers. The IMT group improved significantly their MIP (p < 0.001), peak VO2 (p < 0.001), exercise oxygen uptake at anaerobic threshold (p = 0.001), ventilatory efficiency (p = 0.007), metabolic equivalents (p < 0,001), 6MWT (p < 0.001), and QoL (p = 0.037) as compared to the control group. No changes on diastolic function parameters or biomarkers levels were observed between both groups. In HFpEF patients with low aerobic capacity and non-reduced MIP, IMT was associated with marked improvement in exercise capacity and QoL.

Palau P ，Domínguez E ，Núñez E ，Schmid JP ，Vergara P ，Ramón JM ，Mascarell B ，Sanchis J ，Chorro FJ ，Núñez J ... -  《-》

Impaired Pulmonary Function is an Additional Potential Mechanism for the Reduction of Functional Capacity in Clinically Stable Fontan Patients.

Turquetto ALR ，Canêo LF ，Agostinho DR ，Oliveira PA ，Lopes MICS ，Trevizan PF ，Fernandes FLA ，Binotto MA ，Liberato G ，Tavares GMP ，Neirotti RA ，Jatene MB ... -  《-》