Flexibility: A Hidden But Trainable Morbidity in Pediatric Patients with Congenital Heart Disease.

Flexibility is important for range of motion, muscular performance, and injury prevention with exercise. Promoting exercise is important for patients with congenital and pediatric acquired heart disease (CHD), yet there are a paucity of data addressing flexibility in this population. We hypothesized that flexibility was worse in pediatric patients with CHD than the general population but could be improved with directed training. Patients at Boston Children's Hospital who participated in the pediatric Cardiac Fitness Program between 09/2016 and 11/2022 were retrospectively analyzed. Flexibility was assessed via sit-and-reach (SaR) box. Data from baseline and 60 days into the fitness program intervention were compared to age-matched population norms, and changes over time were assessed. Analyses were also stratified by sex and history of sternotomy. Patients with paired baseline and 60-day data were analyzed (n = 46, age 8-23 years old, 52% male). The mean SaR at baseline for CHD patients was 24.3 cm, significantly lower than the population norm (p = 0.002). The mean for male (n = 24, 21.2 cm) and female (n = 22, 27.2 cm) CHD patients was significantly lower than their respective population norms (p = 0.017 and p = 0.026, respectively). After the fitness intervention, flexibility in CHD patients significantly improved to normal, including patients with a history of sternotomy. Flexibility was significantly lower in CHD patients than the general population, but normalized with training. Further research is warranted to investigate associations of flexibility with other measures of fitness, cardiovascular status, and quality of life, as well as benefits gained with training.

ehealth technology in cardiac exercise therapeutics for pediatric patients with congenital and acquired heart conditions: a summary of evidence and future directions.

Many children and adolescents with congenital and acquired heart disease (CHD) are physically inactive and participate in an insufficient amount of moderate-to-vigorous intensity exercise. Although physical activity (PA) and exercise interventions are effective at improving short- and long-term physiological and psychosocial outcomes in youth with CHD, several barriers including resource limitations, financial costs, and knowledge inhibit widespread implementation and dissemination of these beneficial programs. New and developing eHealth, mHealth, and remote monitoring technologies offer a potentially transformative and cost-effective solution to increase access to PA and exercise programs for youth with CHD, yet little has been written on this topic. In this review, a cardiac exercise therapeutics (CET) model is presented as a systematic approach to PA and exercise, with assessment and testing guiding three sequential PA and exercise intervention approaches of progressive intensity and resource requirements: (1) PA and exercise promotion within a clinical setting; (2) unsupervised exercise prescription; and (3) medically supervised fitness training intervention (i.e., cardiac rehabilitation). Using the CET model, the goal of this review is to summarize the current evidence describing the application of novel technologies within CET in populations of children and adolescents with CHD and introduce potential future applications of these technologies with an emphasis on improving equity and access to patients in low-resource settings and underserved communities.

Positive mindset and exercise capacity in school-aged children and adolescents with congenital heart disease.

Introduction: Patients with congenital heart disease (CHD) have variable degrees of peak oxygen consumption (VO2) that can be improved with supervised fitness training. The ability to exercise is affected by anatomy, hemodynamics, and motivation. Motivation is in part related to mindset, or personal attitudes and beliefs, and a more positive mindset around exercise has been associated with better outcomes. It is unknown whether variations in measured peak VO2 in patients with CHD are related to having a positive mindset. Methods: Patient's ages 8-17 years with CHD were administered quality of life and physical activity questionnaires at the time of their routine cardiopulmonary exercise test. Those with severe hemodynamic burden were excluded. Patients were grouped based on disease classification. Mindset was evaluated via validated questionnaires including a PROMIS Meaning and Purpose (MaP) survey and an Anxiety survey. Pearson correlation coefficients were calculated to estimate the magnitude of the association between percent predicted peak oxygen consumption (pppVO2) and questionnaire scores overall and within CHD subgroups. Results: Eighty-five patients participated; median age was 14.7 years, 53% were female, 66% had complex CHD, 20% had simple CHD, and 14% had single ventricle heart disease. Mean MaP scores were significantly lower in all CHD groups compared to population norms (p < 0.001). As a group, MaP scores were positively associated with the amount of reported physical activity (p = 0.017). In patients with simple CHD, MaP scores were positively associated with pppVO2 (p = 0.015). The association was even stronger for MaP:Anxiety, with worse ratios associated with lower pppVO2 (p = 0.005). Patients with complex and single ventricle CHD did not show a similar association. Conclusions: Patients with CHD, regardless of severity, had lower meaning and purpose scores than the general population, and these scores were associated with amount of reported physical activity. In the simple CHD subset, having a more positive mindset was associated with higher peak VO2 and a more negative mindset with lower peak VO2. This relationship was not seen with more significant CHD. While underlying CHD diagnoses are not modifiable, mindset and peak VO2 are, and consideration should be given to measuring both as each may be a target for intervention.

FORCE Risk Stratification Tool for Pediatric Cardiac Rehabilitation and Fitness Programs.

Risk stratification is required to set an exercise prescription for cardiac rehabilitation, but an optimal scheme for congenital heart disease (CHD) is unknown. We piloted a system based on hemodynamic rather than anatomic factors: function, oxygen level, rhythm, complex/coronary anatomy, and elevated load (FORCE). Feasibility, efficacy, and safety of the FORCE tool were evaluated. Patients < 22 years old participating in the Cardiac Fitness Program at Boston Children's Hospital between 02/2017 and 12/2021 were retrospectively analyzed. Assigned FORCE levels, anatomy, adverse events, fitness and exercise test data were collected. Of 63 attempts at FORCE classification, 62 (98%) were successfully classified while one with restrictive cardiomyopathy was not. Thirty-nine (62%) were FORCE 1, 16 (25%) were FORCE 2, and seven (11%) were FORCE 3. Almost half of FORCE 1 patients had simple or complex CHD and the majority of FORCE 2 patients had single ventricle CHD. FORCE 3 patients were more likely to have serious arrhythmias or cardiomyopathy than those in FORCE 1 or 2 (p < 0.001). Postural orthostatic tachycardia syndrome patients appeared in FORCE 1 only. No adverse events occurred over 958 total sessions. The total number of fitness sessions/participant was similar across FORCE levels. It was feasible to risk stratify patients with CHD using a clinical FORCE tool. The tool was effective in categorizing patients and simple to use. No adverse events occurred with fitness training over nearly 1000 exercise training sessions. Adding diastolic dysfunction to the original model may add utility.

Practices and Procedures in Clinical Pediatric Exercise Laboratories in North America.

Interinstitutional differences in clinical pediatric exercise laboratory (CPEL) practices may affect patient care and efficacy of multicenter research. PURPOSE: To describe current practices/procedures in CPELs and explore differences in CPELs employing exercise physiologists to those that do not. METHODS: A 40-item survey was distributed to CPELs in North America focusing on (1) staffing; (2) exercise stress testing (EST) volumes, reporting, and interpretation; and (3) EST procedures/protocols. RESULTS: Of the 55 responses, 89% were in the United States, 85% were children's hospitals with university affiliation, and 58% were cardiology specific. Exercise physiologists were employed in 56% of CPELs, and 78% had master's degrees or higher. Certifications were required in most CPELs (92% emergency life-support, 27% professional, and 21% clinical). Median volume was 201 to 400 ESTs per year, 80% used treadmill, and 10% used cycle ergometer as primary modalities. Ninety-three percent of CPELs offered metabolic ESTs, 87% offered pulmonary function testing, 20% used institution-specific EST protocols, and 72% offered additional services such as cardiac/pulmonary rehabilitation. CPELS staffing exercise physiologists performed higher volumes of ESTs (P = .004), were more likely to perform metabolic ESTs (P = .028), participated in more research (P < .001), and provided services in addition to ESTs (P = .001). CONCLUSIONS: Heterogeneity in CPELs staffing and operation indicates need for standardization.

Variation in Cardiac Rehabilitation for Pediatric Ventricular Assist Device Recipients Across North America.

Despite increasing utilization of continuous-flow pediatric ventricular assist devices (VAD) in children, data on exercise testing and cardiac rehabilitation (CR) are unknown. We described variation in CR practices and identified barriers to exercise testing and CR. A survey was performed through the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) representing pediatric VAD centers across North America. Descriptive statistics were performed. A multidisciplinary cohort of 52 respondents from 28 pediatric VAD centers responded. Although 38% reported performing exercise testing, most (65%) used 6 minute walk tests rather than formal cycle or treadmill exercise testing. While all respondents refer to physical therapy during the initial inpatient stay for VAD placement, only 52% refer to a CR program. When performed, CR was performed at an ACTION center (84%), a local specialized center (21%), or a home-based CR program (26%). Commonly cited barriers to either CR or exercise testing were inadequate resources, inadequate implementation logistics knowledge, concerns about safety, inability of patients to travel to a CR facility, and concern about utility of exercise testing or CR. Over 90% of centers were interested in implementing a standardized pediatric VAD CR program. Utilization of exercise testing and CR after VAD placement is variable. Despite perceived barriers, most pediatric VAD centers are interested in implementing a standardized CR program for recipients. In response to this interest, we plan to implement a standardized CR protocol to all ACTION pediatric VAD centers in an effort to improve pretransplant waitlist rehabilitation and post-transplant outcomes.

The Adaptation of Pediatric Exercise Testing Programs to the Coronavirus/COVID-19 Pandemic.

OBJECTIVE: Response to the coronavirus/COVID-19 pandemic has resulted in several initiatives that directly impact hospital operations. There has been minimal information on how COVID-19 has affected exercise testing in pediatric patients. DESIGN: A web-based survey was designed and sent to pediatric exercise testing laboratories in the United States and Canada. Questions were designed to understand the initial and ongoing adaptations made by pediatric exercise testing laboratories in response to COVID-19. Results were analyzed as frequency data. RESULTS: There were responses from 42% (35/85) of programs, with 68% (23/34) of laboratories discontinuing all exercise testing. Of the 23 programs that discontinued testing, 15 (65%) are actively working on triage plans to reopen the exercise laboratory. Personal protective equipment use include gloves (96%; 25/26), surgical masks (88%; 23/26), N-95 masks (54%; 14/26), face shields (69%; 18/26), and gowns (62%; 16/26). Approximately 47% (15/32) of programs that typically acquire metabolic measurements reported either ceasing or modifying metabolic measurements during COVID-19. Additionally, 62% (16/26) of the programs that previously obtained pulmonary function testing reported either ceasing or modifying pulmonary function testing. Almost 60% of respondents expressed a desire for additional guidance on exercise laboratory management during COVID-19. CONCLUSIONS: Pediatric exercise testing laboratories largely closed during the early pandemic, with many of these programs either now open or working on a plan to open. Despite this, there remains heterogeneity in how to minimize exposure risks to patients and staff. Standardization of exercise testing guidelines during the COVID-19 pandemic may help reduce some of these differences.

Identifying elements for a comprehensive paediatric cardiac rehabilitation programme.

INTRODUCTION: The aim of this study was to identify relevant content among four important domains for the development and structure of a paediatric cardiac rehabilitation curriculum for young patients with congenital heart disease using a consensus approach. METHODS: A three-round e-Delphi study among congenital heart disease and paediatric exercise physiology experts was conducted. Round 1, experts provided opinions in a closed- and open-ended electronic questionnaire to identify specific elements necessary for inclusion in a paediatric cardiac rehabilitation programme. Round 2, experts were asked to re-rate the same items after feedback and summary data were provided from round 1. Round 3, the same experts were asked to re-rate items that did not reach consensus from round 2. RESULTS: Forty-seven experts were contacted via e-mail to participate on the Delphi panel, 37 consented, 35 completed round 1, 29 completed round 2, and 28 completed the final round. After round 2, consensus was reached in 55 of 60 (92%) questionnaire items across four domains: exercise training, education, outcome metrics, and self-confidence. CONCLUSION: This study established consensus towards programme structure, exercise training principles, educational content, patient outcome measures, and self-confidence promotion. By identifying the key components within each domain, there is potential to benchmark recommended standards and practice guidelines for the development of a paediatric cardiac rehabilitation curriculum to be used and tested by exercise physiologists, paediatric and adult congenital cardiologists, and other healthcare team members for optimising the health and wellness of paediatric patients with congenital heart disease.

Establishing a Comprehensive Pediatric Cardiac Fitness and Rehabilitation Program for Congenital Heart Disease.

Children and adolescents with congenital heart disease often do not have the opportunity, inclination, or education to participate in safe and effective exercise. The consequences of this behavioral pattern affect not only cardiopulmonary parameters, but also psychosocial factors, especially when lack of participation in peer activities or sports leads to isolation and further sedentary behaviors. Importantly, unlike cardiac rehabilitation programs for adults with atherosclerotic disease, the goal for congenital heart disease patients was less about "rehabilitation" and more about promotion of optimal fitness. We thus developed a comprehensive "Cardiac Fitness Program" at Boston Children's Hospital to promote exercise training, enhanced self-confidence, and motivation for patients with congenital heart disease. Since much of sustained fitness relates to consistency and behavior change, we crafted a progressive, goal-oriented exercise curriculum and augmented it with a self-learning workbook of targeted positive mindset practices to develop self-efficacy, an app for motivation and data collection, and exercise videos to demonstrate mechanics and to reiterate a positive message. We now report our experience including program structure and framework, navigating insurance, curriculum development, and outcome measures. Methods employed and barriers encountered in the initial development and execution of this program are reviewed. Key take-aways and further considerations including virtual and home-based programs are discussed.

Incidence and Predictors of Clinically Important and Dangerous Arrhythmias During Exercise Tests in Pediatric and Congenital Heart Disease Patients.

OBJECTIVES: This study quantified the incidence of arrhythmias during pediatric exercise stress tests (ESTs) and evaluated criteria to identify patients at risk of clinically important arrhythmias. BACKGROUND: The incidence of clinically important arrhythmias during pediatric ESTs and criteria for identifying high-risk patients are poorly characterized. METHODS: A retrospective review of ESTs performed from 2013 to 2015 was studied. Arrhythmias were categorized into 4 classes based on need for test termination and intervention. Risk factors evaluated included having an implantable cardioverter-defibrillator (ICD), cardiomyopathy, severe ventricular dysfunction, complex arrhythmia history, coronary disease with concern for ischemia, pulmonary hypertension, select poorly palliated congenital heart disease (CHD), and concerning symptoms. Negative predictive values (NPVs) were calculated. RESULTS: During the study period, 5307 ESTs were performed. Median age of the subjects was 16 years (interquartile range: 13 to 24 years); 20% had complex CHD. At least 1 high-risk criterion was present in 507 tests (10%); having an ICD (37%) and cardiomyopathy (36%) were the most common criteria. Some arrhythmias were seen in 46% of tests, but only 33 events (0.6%) required test termination. Three events (0.06%) required cardiopulmonary resuscitation, all with high-risk criteria. Absence of a high-risk criterion had a 99.7% (95% confidence interval [CI]: 99.5% to 99.8%) NPV for an arrhythmia that required test termination and a 99.96% (95% CI: 99.85% to 99.99%) NPV for an arrhythmia that required intervention beyond test termination. CONCLUSIONS: Although self-terminating arrhythmias are common, dangerous arrhythmias are rare during ESTs in a high-volume pediatric cardiology program. Pre-defined high-risk criteria identified all patients with the most serious events. The absence of any criteria predicted a low risk for arrhythmias that required test termination. These data permitted informed choices regarding supervision of ESTs.

Recovery of oxygen consumption after maximal exercise in children.

PURPOSE: The period of early recovery after exercise is characterized by a rapid payback of the oxygen debt incurred during exercise. The purpose of this study was to test the hypothesis that the oxygen consumption (VO(2)) decline during the first minute of recovery after exercise will be faster in children with a higher peak VO(2). METHODS: We performed a clinically indicated bicycle exercise test in 203 children, aged 15.5 ± 3.2 yr; 33 had healthy heart/minimal heart disease, 59 had left-sided heart disease, 92 had right-sided heart disease, and 19 had postoperative single ventricle. VO(2) was recorded at peak exercise and at 20, 40, and 60 s of recovery. RESULTS: Peak VO(2) in the study cohort was 30.1 ± 8.5 mL·kg(-1)·min(-1) and fell to 24.3 ± 6.7, 19.5 ± 4.9, and 15.3 ± 4.0 mL·kg(-1)·min(-1) at 20, 40, and 60 s of recovery, respectively. VO(2) recovery was slower in children with right-sided heart disease and single ventricle compared with the other 2 groups and was faster in younger children, boys, children with a higher peak VO(2), and in those with a lower RER at peak exercise. In the linear regression analysis, the slope of VO(2) decline during the first minute of recovery was most strongly associated with the peak VO(2) (R(2) = 0.786, P < 0.001). The only other variable that added to the explained variance was peak RER (R(2) = 0.796, P = 0.004). CONCLUSIONS: VO(2) decline during the first minute of recovery after maximum exercise is faster in children with higher peak VO(2). VO(2) recovery may be a useful tool in assessing cardiopulmonary health in children.

Effect of pulmonary artery angioplasty on exercise function after repair of tetralogy of Fallot.

BACKGROUND: The slope of the minute ventilation versus CO2 production relationship (VE/VCO2 slope) is an index of gas exchange efficiency during exercise. In patients with repaired tetralogy of Fallot (rTOF), it correlates negatively with exercise capacity and is one of the best predictors of peak oxygen consumption (VO2). In these patients, the magnitude of the VE/VCO2 slope is related to the severity of pulmonary blood flow maldistribution (PBFM). The purpose of this study was to determine whether, in patients with rTOF, improvements in PBFM after a successful balloon angioplasty procedure (BAP) result in improvements in peak VO2 and gas exchange during exercise. METHODS: Seventeen patients with rTOF and residual pulmonary artery stenoses referred for BAP were recruited. Exercise tests were performed and PBFM determined before and after BAP. RESULTS: Nine patients (group 1) had a successful BAP (ie, improvement of >5 percentage points in PBFM); 8 did not (group 2). Patients in group 1 had significantly greater improvements in VE/VCO2 slope, peak VO2, and peak oxygen pulse (an index of forward stroke volume at peak exercise) than did patients in group 2. A significant correlation existed between the improvement in PBFM and the decline in the VE/VCO2 slope (r = -0.70, P = .002). Changes in peak oxygen pulse accounted for 89% of the improvement in peak VO2. CONCLUSIONS: In these patients, a successful BAP resulted in improved peak VO2 and more efficient gas exchange during exercise. The improvement in peak VO2 appeared to be mediated by an increase in forward stroke volume.

Sustained effects of cardiac rehabilitation in children with serious congenital heart disease.

OBJECTIVE: Past studies have documented the acute benefits of cardiac rehabilitation in children with congenital heart disease. It is not known whether these benefits persist. PATIENTS AND METHODS: Fifteen patients, ages 8 to 17 years, with complex congenital heart disease, whose exercise function immediately after a 12-week cardiac rehabilitation program was superior to that present on a precardiac rehabilitation exercise test, were restudied 6.9 +/- 1.6 months after completion of the cardiac rehabilitation program (approximately 1 year after the precardiac rehabilitation study). Changes in exercise function relative to baseline, precardiac rehabilitation exercise tests were also compared with changes observed in a group of 18 control subjects, with similar diagnoses, who also had 2 exercise tests separated by a year but did not undergo cardiac rehabilitation. RESULTS: The cardiac rehabilitation patients' exercise function did not change significantly over the 6.9-month period after the completion of the cardiac rehabilitation program; percentage of predicted peak oxygen consumption and peak work rate remained significantly superior to baseline, precardiac rehabilitation values. These changes were also associated with improvements in self-esteem, behavior, and emotional state. In contrast, among the control subjects, small, but statistically insignificant declines in peak oxygen consumption and peak work rate were observed on the final exercise test compared with values obtained at baseline, 1 year earlier. The improvements realized by the cardiac rehabilitation patients differed significantly from the concurrent changes observed among the control subjects and appeared to be a result of an increase in the oxygen pulse at peak exercise; significant changes in peak heart rate were not observed. CONCLUSIONS: In patients with congenital heart disease, cardiac rehabilitation produces significant, sustained improvements in exercise function, behavior, self-esteem, and emotional state.

Determinants of exercise function following univentricular versus biventricular repair for pulmonary atresia/intact ventricular septum.

This study aimed to determine whether the exercise capacity of patients with pulmonary atresia/intact ventricular septum (PA/IVS) who have undergone biventricular repair is superior to that of patients with single ventricle repairs and to account for any differences. PA/IVS is generally treated with either biventricular (outflow tract reconstruction) or univentricular (Fontan) palliation. Although biventricular repair is believed to result in superior exercise function, this theory is untested. Symptom-limited programmed bicycle ergonometry with expiratory gas analysis was prospectively performed on all patients with PA/IVS >7 years old seen over 18 months. Nineteen biventricular and 10 Fontan patients (mean age 16.5 +/- 6.5 vs 12.7 +/- 5.0 years, p = 0.12) were enrolled. The exercise capacity of biventricular patients was not statistically superior to that of Fontan patients (predicted peak VO2 83.5 +/- 21% vs 76.0 +/- 17.5%, p = 0.34), although chronotropic function and ventilatory efficiency were significantly better in the former. The peak exercise capacity varied widely within each group, and there was considerable overlap between biventricular and Fontan patients. Within groups, imaging studies did not reliably predict exercise capacity. Most patients in each group had subnormal peak VO2, and there was a trend toward impaired performance with increasing age regardless of type of repair. In conclusion, biventricular repair may not guarantee superior exercise performance over single-ventricle palliation in PA/IVS. Regardless of repair type, aerobic capacity may deteriorate with age and is not reliably predicted by noninvasive imaging. These findings underscore the need for a quantitative, proactive approach to the assessment and preservation of exercise function.

Impact of cardiac rehabilitation on the exercise function of children with serious congenital heart disease.

OBJECTIVES: The exercise capacity of children with congenital heart disease (CHD) is often depressed. This depression is thought to be attributable to (1) residual hemodynamic defects and (2) deconditioning secondary to physical inactivity. We hypothesized that this latter component would be ameliorated by a formal cardiac rehabilitation program designed specifically for children. The objective of this study was to characterize the effect of a cardiac rehabilitation program on the exercise performance of children with CHD and to define the physiologic mechanisms that might account for any improvements that are observed. METHODS: Nineteen patients with CHD who were referred for exercise testing and found to have a peak oxygen consumption (VO2) and/or peak work rate <80% of predicted were enrolled in the study. Sixteen patients (11 Fontan patients, 5 with other CHD) completed the program and had postrehabilitation exercise tests, results of which were compared with the prerehabilitation studies. RESULTS: Improvements were found in 15 of 16 patients. Peak VO2 rose from 26.4 +/- 9.1 to 30.7 +/- 9.2 mL/kg per min; peak work rate from 93 +/- 32 to 106 +/- 34 W, and the ventilatory anaerobic threshold from 14.2 +/- 4.8 to 17.4 +/- 4.5 mL/kg per min. The peak heart rate and peak respiratory exchange ratio did not change, suggesting that the improvements were not attributable merely to an increased effort. In contrast, the peak oxygen pulse rose significantly, from 7.6 +/- 2.8 to 9.7 +/- 4.1 mL/beat, an improvement that can be attributed only to an increase in stroke volume and/or oxygen extraction at peak exercise. No patient experienced rehabilitation-related complications. CONCLUSION: Cardiac rehabilitation can improve the exercise performance of children with CHD. This improvement is mediated by an increase in stroke volume and/or oxygen extraction during exercise. Routine use of formal cardiac rehabilitation may greatly reduce the morbidity of complex CHD.