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Cardiac rehabilitation (CR) is an important tool for improving fitness and quality of life in those with heart disease (HD). Few pediatric centers use CR to care for these patients, and virtual CR is rarely used. In addition, it is unclear how the COVID-19 era has changed CR outcomes. This study assessed fitness improvements in young HD patients participating in both facility-based and virtual CR during the COVID-19 pandemic. This retrospective single-center cohort study included new patients who completed CR from March 2020 through July 2022. CR outcomes included physical, performance, and psychosocial measures. Comparison between serial testing was performed with a paired t test with P < 0.05 was considered significant. Data are reported as mean ± standard deviation. There were 47 patients (19 ± 7.3 years old; 49% male) who completed CR. Improvements were seen in peak oxygen consumption (VO2, 62.3 ± 16.1 v 71 ± 18.2% of predicted, p = 0.0007), 6-min walk (6 MW) distance (401 ± 163.8 v 480.7 ± 119.2 m, p = < 0.0001), sit to stand (16.2 ± 4.9 v 22.1 ± 6.6 repetitions; p = < 0.0001), Patient Health Questionnaire-9 (PHQ-9) (5.9 ± 4.3 v 4.4 ± 4.2; p = 0.002), and Physical Component Score (39.9 ± 10.1 v 44.9 ± 8.8; p = 0.002). Facility-based CR enrollees were less likely to complete CR than virtual patients (60%, 33/55 v 80%, 12/15; p = 0.005). Increases in peak VO2 (60 ± 15.3 v 70.2 ± 17.8% of predicted; p = 0.002) were seen among those that completed facility-based CR; this was not observed in the virtual group. Both groups demonstrated improvement in 6 MW distance, sit-to-stand repetitions, and sit-and-reach distance. Completion of a CR program resulted in fitness improvements during the COVID-19 era regardless of location, although peak VO2 improved more for the in-person group. [ABSTRACT FROM AUTHOR]

Cardiopulmonary exercise testing (CPET) provides clinicians with information vital to the management of pediatric cardiology patients. CPET can also be used to measure cardiorespiratory fitness (CRF) in these patients. CRF is a robust marker of overall health in children. However, a complete understanding of CRF in pediatric cardiology patients is limited by lack of large, standardized CPET databases. Our purpose was to develop a standardized CPET database, describe available data at our institution, and discuss challenges and opportunities associated with this project. CPETs performed from 1993 to present in an urban pediatric hospital were collected and compiled into a research database. Historical data included demographic and clinical variables and CPET outcomes, and additional variables were calculated and coded to facilitate analyses in these cohorts. Patient diagnoses were coded to facilitate sub-analyses of specific cohorts. Quality assurance protocols were established to ensure future database contributions and promote inter-institutional collaborations. This database includes 10,319 CPETs (56.1% male), predominantly using the Bruce Protocol. Patients ranging from ages 6 to 18 years comprise 86.8% of available CPETs. Diagnosis classification scheme includes patients with structurally normal hearts (n = 3,454), congenital heart disease (n = 3,614), electrophysiological abnormalities (n = 2,082), heart transplant or cardiomyopathy (n = 833), and other diagnoses (n = 336). Historically, clinicians were provided with suboptimal interpretive resources for CPET, often generalizing inferences from these resources to non-representative clinical populations. This database supports representative CRF comparisons and establishes a framework for future CRF-based registries in pediatric patients referred for CPET, ultimately improving clinical decision-making regarding fitness in these populations. [ABSTRACT FROM AUTHOR]

Exercise function is well characterized in adults with hypertrophic cardiomyopathy (HCM); however, there is a paucity of data in children and young adults with HCM. Here we sought to characterize exercise function in young people with HCM, understand limitations in exercise function by correlating exercise function parameters with echocardiogram parameters and identify prognostic value of exercise parameters. We performed a retrospective, single-center cohort study characterizing exercise function in patients < 26 years old with HCM undergoing cardiopulmonary exercise testing (CPET). Patients with syndromic HCM or submaximal effort were excluded. We compared exercise function in this cohort to population normal values and measured changes in exercise function over time. We correlated exercise function parameters with echocardiographic parameters and investigated the relationship between exercise test parameters and a clinical composite outcome comprised of significant ventricular arrhythmia, death, or heart transplantation. We identified 229 CPETs performed by 117 patients (mean age at time of first CPET 15.6 ± 3.2 years). Mean %-predicted peak VO2, O2 pulse, and peak heart rate were statistically significantly depressed compared to population normal values and exercise function gradually worsened over time. Abnormal exercise testing correlated closely with echocardiographic indices of diastolic dysfunction. There was a trend toward increased incidence of poor clinical outcome in patients with abnormal exercise function. While adverse clinical outcomes were rare, normal exercise function appears to be a marker of low risk for adverse clinical outcomes in this population. [ABSTRACT FROM AUTHOR]

Previous studies of outcome after operative correction of interrupted aortic arch (IAA) have focused on mortality and rates of reintervention. We sought to investigate the clinical status of children and adolescents after surgery for IAA. A cross-sectional study of subjects with IAA between the ages of 8 and 18 years was performed with the subjects undergoing simultaneous genetic testing, electrocardiogram, cardiac magnetic resonance imaging, cardiopulmonary exercise testing, and assessment of health status and health-related quality of life as well as concurrent retrospective cohort study reviewing their postoperative use of medical care, including operative and transcatheter reinterventions, noncardiac surgeries, and hospitalizations. Twenty-one subjects with IAA with median age of 9 years were studied. Reintervention rates were 38% for left-ventricular outflow tract, 33% for AA, and 24% for both. Rates of reintervention were highest in the first year of life and decreased in subsequent years. Left-ventricular ejection fraction was preserved (72 ± 6%). Maximal oxygen consumption, maximal work, and forced vital capacity were both significantly decreased from age and sex norms (p < 0.0001). Health status and quality of life were both severely decreased. Subjects with IAA demonstrate a significant burden of operative and transcatheter intervention and large magnitude deficits in exercise performance, health status, and health-related quality of life.

After the arterial switch operation (ASO) for transposition of the great arteries (TGA), many patients have an impaired exercise tolerance. Exercise tolerance is determined with cardiopulmonary exercise testing by peak oxygen uptake (VO2peak). Unlike VO2peak, the oxygen uptake efficiency slope (OUES) does not require a maximal effort for interpretation. The value of OUES has not been assessed in a large group of patients after ASO. The purpose of this study was to determine OUES and VO2peak, evaluate its interrelationship and assess whether exercise tolerance is related to ventricular function after ASO. A cardiopulmonary exercise testing, assessment of physical activity score and transthoracic echocardiography (fractional shortening and left/right ventricular global longitudinal peak strain) were performed to 48 patients after ASO. Median age at follow-up after ASO was 16.0 (IQR 13.0–18.0) years. Shortening fraction was normal (36 ± 6%). Left and right global longitudinal peak strain were reduced: 15.1 ± 2.4% and 19.5 ± 4.5%. This group of patients showed lower values for all cardiopulmonary exercise testing parameters compared to the reference values: mean VO2peak% 75% (95% CI 72–77) and mean OUES% 82(95% CI 77–87); without significant differences between subtypes of TGA. A strong-to-excellent correlation between the VO2peak and OUES was found (absolute values: R = 0.90, p < 0.001; normalized values: R = 0.79, p < 0.001). No correlation was found between cardiopulmonary exercise testing results and left ventricle function parameters. In conclusion, OUES and VO2peak were lower in patients after ASO compared to reference values but are strongly correlated, making OUES a valuable tool to use in this patient group when maximal effort is not achievable. [ABSTRACT FROM AUTHOR]

Survivors of palliative surgery for single ventricle heart disease (SVHD) are at risk of poor neurodevelopmental outcomes and reduced exercise capacity. In healthy populations, reduced exercise capacity is related to decreased cognition suggesting a possible relationship between exercise capacity and neurodevelopment. Using cardiopulmonary exercise testing (CPET) and neuropsychological testing (NPT) as indicators of exercise capacity and neurodevelopment, respectively, we hypothesized that in SVHD, higher CPET measures are related to better NPT performance. Patients were retrospectively identified. CPET variables included VO2max, anaerobic threshold, peak heart rate, ventilatory efficiency, and respiratory exchange ratio. NPT instruments were divided into domains measuring attention, executive functioning, adaptive functioning, and emotional functioning. Linear regression was used to test for associations between CPET and NPT. 23 subjects with SVHD met inclusion criteria. On both CPET and NPT, the cohort scored worse than healthy, age-matched subjects. Higher VO2max and anaerobic threshold were associated with better parent-rated overall adaptive functioning (p = 0.01 and p = 0.02, respectively). Higher peak heart rate was related to better sustained visual attention (p = 0.01). In SVHD, CPET measures indicating better exercise capacity were positively associated with a subset of scores on NPT. Larger, multisite studies implementing cardiorespiratory fitness intervention and incorporating cognitive outcome measures will be needed to better characterize the relationship between neurodevelopment and functional capacity in this population. Results may assist in providing anticipatory guidance and optimizing post-Fontan developmental trajectories. [ABSTRACT FROM AUTHOR]

Previous pediatric exercise test criteria for aortic stenosis severity were based on cardiac catheterization assessment, whereas current criteria are based on echocardiographic valve gradients. We sought to correlate exercise test criteria with echocardiographic assessment of severity. We report 65 studies, 51 patients (mean age of 13 ± 4 years; 75% males), with aortic stenosis (AS) who had a maximal exercise test between 2005 and 2016. We defined three groups based on resting mean Doppler gradient across their aortic valve: severe AS (n = 10; gradient of ≥ 40 mmHg), moderate AS (n = 20; gradient 25–39 mmHg), and mild AS (n = 35; gradient ≤ 24 mmHg). We studied symptoms (chest pain) during exercise, resting electrocardiogram changes (left ventricular hypertrophy [LVH]), complex arrhythmias during exercise, change in exercise systolic blood pressure (SBP; delta SBP = peak SBP-resting SBP), exercise duration, work, echocardiogram parameters (LVH), and ST–T wave changes with exercise. Additionally, we compared work and delta SBP during exercise with 117 control males and females without heart disease. Severe AS patients have statistically significant differences when compared with mild AS in ST–T wave depression during exercise, LVH on resting electrocardiogram, and echocardiogram. There was a significant difference in delta SBP between severe AS and normal controls (delta SBP 21.6 vs. 46.2 mmHg), and between moderate AS and normal controls (delta SBP 32 vs. 46.2 mmHg). There were no significant complications during maximal exercise testing. Children with echocardiographic severe and moderate AS have exercise testing abnormalities. Exercise test criteria for severity of AS were validated for echocardiographic criteria for AS severity. [ABSTRACT FROM AUTHOR]

Exercise performance is variable and often impaired in patients with repaired tetralogy of Fallot (rTOF). We sought to identify factors associated with exercise performance by comparing high to low performers on cardiopulmonary exercise testing (CPET) in patients with rTOF. We conducted a cross-sectional study of subjects presenting for CPET who underwent echocardiograms at rest and peak exercise. Patients with pacemakers and arrhythmias were excluded. Right ventricular (RV) global longitudinal strain was used as a measure of systolic function. Pulmonary insufficiency (PI) was assessed with the diastolic systolic ratio and the diastolic systolic time-velocity integral ratio by Doppler interrogation of the pulmonary artery. CPET measures included percent-predicted maximum VO2\% mVO2, percent-predicted maximum work and oxygen pulse. High versus low performers were identified as those achieving \% mVO2 of at least 80% or falling below, respectively. Differences in echocardiographic parameters from rest to peak exercise were examined using mixed-effects regression models. Compared to the low performers (n = 17), high performers (n = 12) were younger (12.8 ± 3.3 years vs. 18.3 ± 4.8 years), had normal chronotropic response (peak heart rate > 185 bpm) with greater heart rate reserve and superior physical working capacity. High performers also had a greater reduction in PI at peak exercise, despite greater PI severity at rest. Oxygen pulse was comparable between groups. For both groups, there was no association of PI severity and RV systolic function at rest with exercise parameters. There was no group difference in the magnitude of change in RV strain and diastolic parameters from rest to peak exercise. Chronotropic response to exercise appears to be an important parameter with which to assess exercise performance in rTOF. Chronotropic health should be taken into consideration in this population, particularly given that RV function and PI severity at rest were not associated with exercise performance. [ABSTRACT FROM AUTHOR]

Adult congenital heart disease (ACHD) patients often require repeat cardiothoracic surgery, which may result in significant morbidity and mortality. Currently, there are few pre-operative risk assessment tools available. In the general adult population, pre-operative cardiopulmonary exercise testing (CPET) has a predictive value for post-operative morbidity and mortality following major non-cardiac surgery. The utility of CPET for risk assessment in ACHD patients requiring cardiothoracic surgery has not been evaluated. Retrospective chart review was conducted on 75 ACHD patients who underwent CPET less than 12 months prior to major cardiothoracic surgery at Children’s Hospital of Wisconsin. Minimally invasive procedures, cardiomyopathy, acquired heart disease, single ventricle physiology, and heart transplant patients were excluded. Demographic information, CPET results, and peri-operative surgical data were collected. The study population was 56% male with a median age of 25 years (17-58). Prolonged post-operative length of stay correlated with increased ventilatory efficiency slope (VE/VCO2 slope) (P = 0.007). Prolonged intubation time correlated with decreased peak HR (P = 0.008), decreased exercise time (P = 0.002), decreased heart rate response (P = 0.008) and decreased relative peak oxygen consumption (P = 0.034). Post-operative complications were documented in 59% of patients. While trends were noted between post-operative complications and some measurements of exercise capacity, none met statistical significance. Future studies may further define the relationship between exercise capacity and post-operative morbidity in ACHD patients. [ABSTRACT FROM AUTHOR]

Tetralogy of Fallot is the most common form of cyanotic congenital heart disease. As a result of the surgical strategies employed at the time of initial repair, chronic pulmonary regurgitation (PR) is prevalent in this population. Despite sustained research efforts, patient selection and timing of pulmonary valve replacement (PVR) to address PR in young asymptomatic patients with repaired tetralogy of Fallot (rToF) remain a fundamental but as yet unanswered question in the field of congenital heart disease. The ability of the heart to compensate for the chronic volume overload imposed by PR is critical in the evaluation of the risks and benefits of PVR. The difficulty in clarifying the functional impact of PR on the cardiovascular capacity may be in part responsible for the uncertainty surrounding the timing of PVR. Cardiopulmonary exercise testing (CPET) may be used to assess abnormal cardiovascular response to increased physiologic demands. However, its use as a tool for risk stratification in asymptomatic adolescents and young adults with rToF is still ill-defined. In this paper, we review the role of CPET as a potentially valuable adjunct to current risk stratification strategies with a focus on asymptomatic rToF adolescents and young adults being considered for PVR. The role of maximal and submaximal exercise measurements to identify young patients with a decreased or borderline low peak VO resulting from impaired ventricular function is explored. Current knowledge gaps and research perspectives are highlighted. [ABSTRACT FROM AUTHOR]

The first patients to undergo a successful arterial switch operation (ASO) for d-transposition of the great arteries (D-TGA) are now entering their fourth decade of life. Past studies of ASO survivors' exercise function have yielded conflicting results. We therefore undertook this study to describe the current function of ASO survivors, to identify factors related to inferior exercise performance and to determine whether their exercise function tends to deteriorate over time. A retrospective cohort study was designed examining all patients with D-TGA after the ASO who underwent comprehensive cardiopulmonary exercise testing (CPET). Patients with palliative surgery prior to ASO, ventricular hypoplasia or severe valvar dysfunction were excluded from the study. Data from CPETs in which the peak respiratory exchange ratio was <1.09 were also excluded. We identified 113 patients who met entry criteria and had 186 CPX at our institution between 1/2002 and 1/2013; 41 patients had at least 2 qualifying CPX. Mean age at the time of the initial test was 17 ± 1 year. Peak oxygen consumption (VO2) averaged 84 ± 2 % predicted. Peak VO2 was lower among patients with repaired ventricular septal defects (82 ± 4 vs. 86 ± 3 % predicted; p < 0.05) and among patients with ≥ moderate right-sided obstructive lesions (77 ± 5 vs. 87 ± 3 % predicted; p < 0.05). Surgery prior to 1991 was also associated with a lower peak VO2 (81 ± 3 vs. 87 ± 3 % predicted; p < 0.01). The mean % predicted peak heart rate was 92 ± 1 %, with no significant difference between any of the subgroups. Non-diagnostic exercise-induced STT changes developed in 10 patients (12 studies). In the subgroup with at least 2 exercise tests, the annual decline in % predicted peak VO2 was quite slow (−0.3 % points/year; p < 0.01 vs. expected normal age-related decline). The exercise capacity of ASO survivors is well preserved and is only mildly reduced compared to normal subjects. Moreover, there is only a slight deterioration in exercise capacity over time. VSD repair, residual right-sided obstructive lesions, and earlier surgical era are associated with worse exercise performance. Peak heart rate was preserved with no significant change in follow up testing. [ABSTRACT FROM AUTHOR]

Cardiopulmonary exercise testing (CPET) is a common method of evaluating patients with a Fontan circulation. Equations to calculate predicted CPET values are based on children with normal circulation. This study aims to create predictive equations for CPET variables solely based on patients with Fontan circulation. Patients who performed CPET in the multicenter Pediatric Heart Network Fontan Cross-Sectional Study were screened. Peak variable equations were calculated using patients who performed a maximal test (RER > 1.1) and anaerobic threshold (AT) variable equations on patients where AT was adequately calculated. Eighty percent of each cohort was randomly selected to derive the predictive equation and the remaining served as a validation cohort. Linear regression analysis was performed for each CPET variable within the derivation cohort. The resulting equations were applied to calculate predicted values in the validation cohort. Observed versus predicted variables were compared in the validation cohort using linear regression. 411 patients underwent CPET, 166 performed maximal exercise tests and 317 had adequately calculated AT. Predictive equations for peak CPET variables had good performance; peak VO, R = 0.61; maximum work, R = 0.61; maximum O pulse, R = 0.59. The equations for CPET variables at AT explained less of the variability; VO at AT, R = 0.15; work at AT, R = 0.39; O pulse at AT, R = 0.34; VE/VCO at AT, R = 0.18; VE/VO at AT, R = 0.14. Only the models for VE/VCO and VE/VO at AT had significantly worse performance in validation cohort. Of the 8 equations for commonly measured CPET variables, six were able to be validated. The equations for peak variables were more robust in explaining variation in values than AT equations. [ABSTRACT FROM AUTHOR]

Previous studies of outcome after operative correction of interrupted aortic arch (IAA) have focused on mortality and rates of reintervention. We sought to investigate the clinical status of children and adolescents after surgery for IAA. A cross-sectional study of subjects with IAA between the ages of 8 and 18 years was performed with the subjects undergoing simultaneous genetic testing, electrocardiogram, cardiac magnetic resonance imaging, cardiopulmonary exercise testing, and assessment of health status and health-related quality of life as well as concurrent retrospective cohort study reviewing their postoperative use of medical care, including operative and transcatheter reinterventions, noncardiac surgeries, and hospitalizations. Twenty-one subjects with IAA with median age of 9 years were studied. Reintervention rates were 38 % for left-ventricular outflow tract, 33 % for AA, and 24 % for both. Rates of reintervention were highest in the first year of life and decreased in subsequent years. Left-ventricular ejection fraction was preserved (72 ± 6 %). Maximal oxygen consumption, maximal work, and forced vital capacity were both significantly decreased from age and sex norms ( p < 0.0001 ). Health status and quality of life were both severely decreased. Subjects with IAA demonstrate a significant burden of operative and transcatheter intervention and large magnitude deficits in exercise performance, health status, and health-related quality of life. [ABSTRACT FROM AUTHOR]

Cardiopulmonary exercise testing (CPET), particularly maximal oxygen consumption (VOmax), has been used to assess the outcome for patients with palliated congenital heart disease (CHD). Small studies correlating VOmax with noninvasive imaging measures of ventricular function have led to the hypothesis that VOmax reflects cardiac performance. In other settings, physical training is associated with increased VOmax. The authors hypothesized that habitual exercise correlates with VOmax to a greater degree than ventricular function in a relatively healthy cohort of patients with palliated CHD. The habitual exercise behavior of 208 subjects with conotruncal abnormalities (tetralogy of Fallot, truncus arteriosus, and interrupted aortic arch) at the time of previously performed, study-based CPET and cardiac magnetic resonance imaging (CMR) were retrospectively assessed via questionnaire. The association of VOmax with habitual exercise duration and CMR measures of ventricular function was tested. Of 208 subjects, 89 (43 %) completed questionnaires, and 78 % of the 89 patients had a concurrent CMR. The mean VOmax was 76 ± 21 % of that predicted. The CMR-assessed left ventricular ejection fraction was 67.6 ± 7.4 %. The hours of habitual exercise per week correlated with VOmax ( p < 0.001; r = 0.14). No association was found between right and left ventricular ejection fraction, cardiac index, or right ventricular end-diastolic volume and VOmax. In this study, VOmax correlated with habitual exercise to a greater degree than CMR measurements of ventricular function. These findings highlight the importance of considering the contribution of noncardiac factors when exercise data in both clinical and research settings are interpreted. The contribution of these factors to clinical outcomes deserves further study. [ABSTRACT FROM AUTHOR]

Cardiopulmonary exercise testing (CPET) provides assessment of the integrative responses involving the pulmonary, cardiovascular, and skeletal muscle systems. Application of exercise testing remains limited to children who are able to understand and cooperate with the exercise protocol. Near-infrared spectroscopy (NIRS) provides a noninvasive, continuous method to monitor regional tissue oxygenation (rSO2). Our specific aim was to predict anaerobic threshold (AT) during CPET noninvasively using two-site NIRS monitoring. Achievement of a practical noninvasive technology for estimating AT will increase the compatibility of CPET. Patients without structural or acquired heart disease were eligible for inclusion if they were ordered to undergo CPET by a cardiologist. Data from 51 subjects was analyzed. The ventilatory anaerobic threshold (VAT) was computed on $$ {\text{V}}_{{{\text{CO}}_{2} }} $$ and respiratory quotient post hoc using the standard V-slope method. The inflection points of the regional rSO2 time-series were identified as the noninvasive regional NIRS AT for each of the two monitored regions (cerebral and kidney). AT calculation made using an average of kidney and brain NIRS matched the calculation made by VAT for the same patient. Two-site NIRS monitoring of visceral organs is a predictor of AT. [ABSTRACT FROM AUTHOR]