Double Ventricular Response with Aberrant Conduction Leading to Ventricular Dysfunction

Double ventricular response (DVR), where a single P wave results in two QRS complexes, is a rare presentation of dual AV node physiology. It has been associated with ventricular dysfunction in the setting of incessant tachycardia. We present the case of an otherwise healthy adolescent who had frequent DVR without tachycardia leading to left ventricular dysfunction. Slow pathway modification led to a significant reduction in ectopy and normalization of ventricular function. This highlights that DVR without tachycardia might lead to ventricular dysfunction in pediatric patients. Slow pathway modification with reduction of ectopy may be sufficient to restore ventricular function.

(F)utility of preoperative pulmonary function testing in pectus excavatum to assess severity

PURPOSE

The utility of pulmonary function testing (PFT) in pectus excavatum (PE) has been subject to debate. Although some evidence shows improvement from preoperative to postoperative values, the clinical significance is uncertain. A high failure-to-completion rate for operative PFT (48%) was identified in our large institutional cohort. With such a high non-completion rate, we questioned the overall utility of PFT in the preoperative assessment of PE and sought to evaluate if other measures of PE severity or cardiopulmonary function could explain this finding.

METHODS

Demographics, clinical findings, and results from cardiac MRI, PFT (spirometry and plethysmography), and cardiopulmonary exercise tests (CPET) were reviewed in 270 patients with PE evaluated preoperatively between 2015 and 2018. Regression modeling was used to measure associations between PFT completion and cardiopulmonary function.

RESULTS

There were no differences in demographics, symptoms, connective tissue disorders, or multiple indices of pectus severity and cardiac deformation in PFT completers versus non-completers. While regression analysis revealed higher RVEF, LVEF, and LVEF-Z scores, lower RV-ESV/BSA, LV-ESV/BSA, and LV-ESV/BSA-Z scores, and abnormal breathing reserve in PFT completers vs. non-completers, these findings were not consistent across continuous and binary analyses.

CONCLUSIONS

We found that PFT completers were not significantly different from non-completers in most structural and functional measures of pectus deformity and cardiopulmonary function. Inability to complete PFT is not an indicator of pectus severity.

Facility-Based and Virtual Cardiac Rehabilitation in Young Patients with Heart Disease During the COVID-19 Era

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.

Microwave demonstration of Purcell effect enhanced radiation efficiency

We experimentally demonstrate a Purcell effect-based design technique for improved impedance matching, and thus enhanced the reflection coefficient from a small microwave emitter. Using an iterative process centred on comparing the phase of the radiated field of the emitter in air with that of the emitter in a dielectric environment, we optimise the structure of a dielectric hemisphere above a ground plane surrounding a small monopolar microwave emitter in order to maximise its radiation efficiency. The optimised system shows very strong coupling between the emitter and two omnidirectional radiation modes at 1.99 GHz and 2.84 GHz, yielding Purcell enhancement factors of 1762 and 411 times increase respectively, and near perfect radiation efficiency.

Cardiac Tamponade Related to a Large Pericardial Mass in a Female with Juvenile Idiopathic Arthritis

We report the case of a young female with juvenile idiopathic arthritis presenting with cardiac tamponade secondary to an unusual pericardial mass. Pericardial masses are typically incidental findings. In rare circumstances they can cause compressive physiology warranting urgent intervention. She required surgical excision which revealed a pericardial cyst encapsulating a chronic solidified hematoma. Though certain inflammatory disorders are associated with myopericarditis, to our knowledge this is the first reported case of a pericardial mass in a well-controlled young patient. We theorize her immunosuppressant therapy resulted in hemorrhage into a pre-existing pericardial cyst, suggesting the need for further follow-up in those on adalimumab therapy.

Pediatric Cardiology Fellowship Standards for Training in Exercise Medicine and Curriculum Outline

Over the past 2 decades, fundamentals of exercise medicine, including clinical exercise testing, assessment and promotion of physical activity, exercise prescription, and supervised exercise training/rehabilitation programming have demonstrated considerable clinical value in the management of children and adolescents with congenital and acquired heart disease. Although the principles of exercise medicine have become an integral component in pediatric cardiology, there are no standardized training recommendations for exercise physiology during pediatric cardiology fellowship at this time. Thus, the Pediatric Cardiology Exercise Medicine Curriculum Committee (PCEMCC) was formed to establish core and advanced exercise physiology training recommendations for pediatric cardiology trainees. The PCEMCC includes a diverse group of pediatric cardiologists, exercise physiologists, and fellowship program directors. The expert consensus training recommendations are by no means a mandate and are summarized herein, including suggestions for achieving the minimum knowledge and training needed for general pediatric cardiology practice.

Long-term exercise and pulmonary function outcomes in a contemporary cohort of children with congenital diaphragmatic hernia

OBJECTIVE

Congenital diaphragmatic hernia (CDH) survivors are at risk for long-term exercise impairment and pulmonary morbidity, but the generalizability of prior reported cohorts are limited by reduced disease severity and older surgical eras. We assessed the mid-childhood exercise and pulmonary function outcomes in a contemporary cohort of CDH survivors.

STUDY DESIGN

In this retrospective cohort study, we identified 36 consecutive pediatric CDH survivors who underwent cardiopulmonary exercise testing (CPET) and spirometry from 2014 to 2021. Inferential statistics compared survivors with age-, sex-, and size-matched healthy controls; univariate analyses identified factors associated with abnormal testing.

RESULTS

Maximal effort CPET and resting spirometry were completed by 27/36 (75%) and 31/36 (86%) subjects, respectively (median age: 8.1 years [interquartile range: 7.5, 10]; 16 females [44%]). Abnormal CPET (percent predicted [pp] peak VO₂  < 80%) was more common in the CDH cohort (12 vs. 1, p < 0.001) and associated with longer neonatal intensive care unit (NICU) stay (p = 0.02) and oxygen therapy at discharge (p = 0.03). Exercise impairment was mild (pp peak VO₂ 70%-80%), moderate (60%-70%), and severe (<60%) in 6, 4, and 2 survivors, respectively. Abnormal spirometry was more common in the CDH cohort (21 vs. 3, p < 0.001; obstructive [n = 15], restrictive [n = 6]) and associated with decreased gestational age (p = 0.046), longer mechanical ventilation in the NICU (p = 0.02), and orthopedic abnormalities (p = 0.03).

CONCLUSION(S)

Exercise capacity was normal or mildly impaired in most CDH survivors, however, approximately two-thirds demonstrated abnormal spirometry. Impaired exercise capacity and lung function were associated with severity of lung disease postnatally. These data support cardiopulmonary follow-up throughout childhood.

Effects of a zero-gravity treadmill on body composition and cardiorespiratory fitness after Achilles surgery in a Masters runner

Zero-gravity treadmills allow alterations in training load. Data are lacking on the utilization of this strategy to allow injured Masters-level athletes to return to activity and regain their fitness. A 6-week training program was designed for a 39-year-old male runner recovering from Achilles surgery using a zero-gravity treadmill. Three training sessions per week were performed with gradually increasing loads. Cardiopulmonary exercise testing and bioelectrical impedance analysis were performed before and after program completion. Following the training program, the athlete was able to return to full weight-bearing running. On cardiopulmonary exercise testing, there were improvements in peak oxygen consumption (42.9 vs 47.3 mL/min/kg; 118.6% vs 130.5% of predicted). On bioelectrical impedance analysis, there were small improvements in total weight, skeletal muscle mass, and adiposity felt to be within the standard of error for bioelectrical impedance analysis. In conclusion, load-altering exercise may be helpful for the Masters-level athlete recovering from Achilles tendon surgery.

Stable fitness during COVID-19: Results of serial testing in a cohort of youth with heart disease

Background

Little is known about how sport and school restrictions early during the novel coronavirus 2019 (COVID-19) pandemic impacted exercise performance and body composition in youth with heart disease (HD).

Methods

A retrospective chart review was performed on all patients with HD who had serial exercise testing and body composition via bioimpedance analysis performed within 12 months before and during the COVID-19 pandemic. Formal activity restriction was noted as present or absent. Analysis was performed with a paired t-test.

Results

There were 33 patients (mean age 15.3 ± 3.4 years; 46% male) with serial testing completed (18 electrophysiologic diagnosis, 15 congenital HD). There was an increase in skeletal muscle mass (SMM) (24.1 ± 9.2-25.9 ± 9.1 kg, p < 0.0001), weight (58.7 ± 21.5-63.9 ± 22 kg, p < 0.0001), and body fat percentage (22.7 ± 9.4-24.7 ± 10.4%, p = 0.04). The results were similar when stratified by age <18 years old (n = 27) or by sex (male 16, female 17), consistent with typical pubertal changes in this predominantly adolescent population. Absolute peak VO₂ increased, but this was due to somatic growth and aging as evidenced by no change in % of predicted peak VO₂. There remained no difference in predicted peak VO₂ when excluding patients with pre-existing activity restrictions (n = 12). Review of similar serial testing in 65 patients in the 3 years before the pandemic demonstrated equivalent findings.

Conclusions

The COVID-19 pandemic and related lifestyle changes do not appear to have had substantial negative impacts on aerobic fitness or body composition in children and young adults with HD.

Pediatric youth who have obesity have high rates of adult criminal behavior and low rates of homeownership

Objectives:

The social outcomes in adulthood for pediatric patients with obesity are not well-described. This study investigated lifetime criminal behavior and homeownership in youth with obesity.

Methods:

Retrospective data on all children enrolled in the weight management program from 1999 to 2009 and who completed exercise testing were collected. Demographic and public record collection included body habitus, death records, real estate transactions, and criminal conviction history with comparisons made to published normative data.

Results:

In the children with obesity studied (N = 716; 12.0 ± 3.1 years old), the now-adult patients (28.5 ± 3.7 years) had a 1.5% mortality rate (11/716). Overall, 9.6% of these adults were convicted of a felony compared to ~7% lifetime prevalence in Ohio (p = 0.03). Also, 14.7% of study patients purchased a home compared to 38.3% of Midwest adults <30 years old (p < 0.0001). Mortality, history of a criminal conviction, or homeownership was associated with any exercise or study parameter.

Conclusion:

Children with obesity appear to have greater social risk than their peers in adulthood with higher rates of criminal behavior and lower rates of homeownership. This appears to highlight the need for treatment in this vulnerable group of children and young adults.

Arrhythmia Burden and Heart Rate Response During Exercise in Anderson-Fabry Disease

Patients with Anderson-Fabry disease (AFD) have an elevated incidence of resting arrhythmias and ischemic heart disease, but their exercise arrhythmia burden and ischemic changes are not well understood. In addition, little research has been done on heart rate recovery in these patients. We retrospectively reviewed charts of patients with AFD who underwent maximal effort cardiopulmonary exercise testing (CPET) (n=44; 38.2 ± 13.8 yr; 23 men) from 2012 through 2018. Electrocardiographic, Holter monitoring, echocardiographic, cardiac magnetic resonance imaging, and patient demographic data were collected. No patient had adverse events that necessitated CPET termination, whereas 25 (57%) had ectopy during CPET, including 3 (7%) with frequent premature atrial contractions and 5 (11%) with frequent premature ventricular contractions. The ectopic burden was higher during resting electrocardiographic monitoring before exercise. In addition, 7 patients (16%) had pathologic ST-segment or T-wave changes on CPET, defined as ST-segment changes ≥2 mm. Among the patients who had concurrent cardiac magnetic resonance findings with their CPET (n=27), ST-segment or T-wave changes were associated with left ventricular myocardial mass (r=0.43, P=0.02). Chronotropic incompetence was seen during CPET in 28 patients (64%); however, only 2 patients (4%) had abnormal heart rate recovery at 1 minute. This study shows that patients with AFD can safely undergo exercise testing but have a high incidence of exercise-induced arrhythmias and ischemic changes. Ischemic electrocardiographic changes during exercise testing are associated with myocardial mass. Despite the chronotropic incompetence associated with AFD, heart rate recovery appears to be generally preserved in these patients.

Abdominal CT and MRI Findings of Portal Hypertension in Children and Adults with Fontan Circulation

Background Portal hypertension in the Fontan circulation is a function of elevated systemic venous pressure and liver fibrosis. Purpose To quantify the prevalence of radiologic evidence of portal hypertension and elevated VAST score (one point each for varices, ascites, splenomegaly, and thrombocytopenia) of 2 or greater in children and adults with Fontan circulation and to determine the association with hemodynamics and adverse outcomes. Materials and Methods This was a retrospective study of individuals with Fontan circulation who underwent abdominal MRI or CT for focal liver lesion surveillance between January 2012 and December 2019. Portal hypertension was defined as the presence of at least two of the following: varices, ascites, or splenomegaly. Fontan deterioration was defined as a composite of heart failure signs or symptoms requiring diuretic escalation, placement of a ventricular assist device, heart transplant, or death. Relationships between variables and the composite end point were assessed using univariable and multivariable logistic regression. Results A total of 123 patients (age range, 9-55 years; 32 children) were evaluated (median age, 23 years; IQR, 17-30 years; 63 male patients). Median time since diagnosis of Fontan circulation was 16 years (IQR, 12-23 years). Twenty-five of the 123 patients (20%) had radiologic evidence of portal hypertension, and 34 (28%) had a VAST score of 2 or greater. Fontan deterioration occurred in 25 of the 123 patients (20%); median follow-up duration was 0.4 year (IQR, 0.1-3.1 years). Compared with patients who had Fontan circulation without deterioration, patients with Fontan deterioration were more likely to have moderate or severe ventricular systolic dysfunction (P < .01), moderate or severe atrioventricular valve regurgitation (P < .01), higher Fontan pressure (P = .01), radiologic evidence of portal hypertension (P < .01), and VAST score of 2 or greater (P < .01). Conclusion Radiologic evidence of portal hypertension at abdominal imaging in children and adults with Fontan circulation was associated with higher venous pressures and an increased risk for Fontan deterioration. These characteristics may be used to identify patients who warrant comprehensive hemodynamic evaluation. © RSNA, 2022.

Abnormal maximal and submaximal cardiopulmonary exercise capacity in pediatric stem cell transplant recipients despite normal standard echocardiographic parameters: a pilot study

BACKGROUND

Left ventricular systolic dysfunction is a known complication of stem cell transplant (SCT). There has been minimal research to determine if subclinical cardiac dysfunction exists in SCT patients utilizing tools other than standard echocardiography, such as maximal and submaximal effort cardiopulmonary exercise testing (CPET) and vascular function studies.

OBJECTIVE

The objective of this study was to determine the rate of subclinical cardiac dysfunction in patients with normal ejection fraction after SCT, identified by abnormal values by CPET, tissue-Doppler imaging, and arterial stiffness measurements and to further describe submaximal exercise test measures in this population.

STUDY DESIGN

A prospective cohort study of SCT survivors who were at least three years post-SCT without prior anthracycline or radiation exposure and with preserved systolic function (LV ejection fraction > 50%) was performed to evaluate for abnormalities in exercise, vascular function, and diastolic function in an effort to detect subclinical dysfunction in SCT patients.

RESULTS

There were 11 patients (12.4±3.8-years-old) included in the study. No patients had diastolic dysfunction. All patients completed a maximal effort exercise test, and 73% (8/11) had abnormal peak oxygen consumption (VO₂peak), which is a measure of aerobic fitness. However, during submaximal effort CPET, 45% (5/11) had an abnormal VO₂ at anaerobic threshold (i.e. the point in exercise where aerobic transitions to anaerobic metabolism and fatigue starts), and 64% (7/11) had an abnormal oxygen uptake efficiency slope (a measure that relates VO₂peak to total ventilation). 86% (6/7) of the patients with an abnormal oxygen uptake efficiency slope ultimately had an abnormal VO₂peak. There were no vascular function abnormalities.

CONCLUSION

Pediatric survivors of SCT often have abnormal maximal and submaximal exercise capacity without vascular or cardiac dysfunction.

EKG Abnormalities in a Youth Athlete Following COVID-19: It's Not Always Myocarditis!

COVID-19 associated myocarditis following mild infections is rare while incidental findings may be more common. A young athlete fully recovered from a mild COVID-19 infection presented with inferolateral T-wave inversions and left ventricular hypertrophy on imaging. Exercise testing aided in correctly diagnosing the patient with masked systolic hypertension.

Ventilatory limitations are not associated with dyspnea on exertion or reduced aerobic fitness in pectus excavatum

Exercise intolerance and chest pain are common symptoms in patients with pectus excavatum. To assess if the anatomic extent of pectus deformities determined by the correction index (CI) is associated with a pulmonary impairment at rest and during exercise we performed a retrospective review on pectus patients in our center who completed a symptom questionnaire, cardiopulmonary exercise test (CPET), pulmonary function tests (PFT), and chest magnetic resonance imaging. Of 259 patients studied, dyspnea on exertion and chest pain was reported in 64% and 41%, respectively. Peak oxygen uptake (VO₂ ) was reduced in 30% and classified as mild in two-thirds. A pulmonary limitation during exercise was identified in less than 3%. Ventilatory limitations on PFT was found in 26% and classified as mild in 85%. Obstruction was the most common abnormal pattern (11%). There were no differences between patients with normal or abnormal PFT patterns for the CI, VO_2, or percentage reporting dyspnea or chest pain. Scatter plots demonstrated significant but weak inverse relationships between the CI and lung volumes at rest and during exercise. Multivariable linear regression modeling evaluating predictors of VO₂ demonstrated positive associations with the forced expiratory volume at one second and a negative association with the CI. We conclude that resting PFT patterns have poor correlation with the anatomic extent of the pectus defect, symptomatology or aerobic fitness. Pulmonary limitations on CPET are uncommon and lung volumes during exercise are only minimally associated with the CI.

Left Atrial Strain in the Repaired Tetralogy of Fallot Population: Comparisons to Biventricular Function, Native T1 Values, Exercise Parameters and Healthy Controls

BACKGROUND

Non-invasive imaging markers in patients with repaired tetralogy of Fallot (rTOF) are still being investigated to inform clinical decision making. Atrial function is a prognostic indicator in many acquired and congenital heart diseases. We sought to examine the relationship between cardiac MRI (CMR)-derived indices of left atrial (LA) function, native left ventricular (LV) T1 values, biventricular systolic function, and exercise capacity in rTOF.

METHODS

Sixty-six patients with rTOF without prior pulmonary valve replacement who underwent CMR (median age 18.5 years) were identified. Twenty-one adult rTOF patients (age range 19-32 years) were compared with 20 age-matched healthy volunteers (age range 19-34 years). LA reservoir, conduit, and pump global longitudinal strain (GLS) and strain rate (SR) were determined by tissue tracking. Native LV T1 values were measured on rTOF patients. Pearson correlations were performed to determine bivariate associations.

RESULTS

Adult rTOF patients had higher pump GLS, pump:conduit, and pump:reservoir GLS ratios, and lower conduit:reservoir GLS ratio, LV ejection fraction (EF), and right ventricular EF compared to controls (p < 0.001 for each comparison). LA conduit:reservoir GLS and pump:reservoir GLS had correlations to native LV T1 (ρ = 0.26, p = 0.03 and ρ = - 0.26, p = 0.03, respectively). LA reservoir SR had positive correlation to RV EF (ρ = 0.27, p = 0.03). There were no statistically significant correlations between LA function and exercise capacity.

CONCLUSIONS

LA function is altered in adolescent and young adult patients with rTOF indicating worse diastolic function and relates to increasing native LV T1 values. Future studies are indicated to investigate the progression of adverse atrial-ventricular interactions and poor outcomes in this population.

Peripheral venous pressure changes during exercise are associated with adverse Fontan outcomes

OBJECTIVE

Elevated central venous pressure (CVP) plays an important role in the development of adverse Fontan outcomes. Peripheral venous pressure (PVP) has been validated as a surrogate for CVP in Fontan patients. We hypothesised that PVP in response to exercise will be associated with a greater prevalence of Fontan morbidity.

METHODS

Adult Fontan patients had cardiopulmonary exercise testing (CPET) with PVP monitoring in the upper extremity between 2015 and 2018. PVP at rest, during unloaded cycling and at peak exercise was compared between those with and without adverse Fontan outcomes including arrhythmia, unscheduled hospital admissions, heart failure requiring diuretics, need for reintervention and a composite outcome of the above morbidities, heart transplantation and death.

RESULTS

Forty-six patients with a mean age at CPET of 26.9±9.5 years. During exercise, PVP increased from 13.6±3.5 mm Hg at rest, to 16.5±3.9 mm Hg during unloaded cycling, to 23.0±5.5 mm Hg at peak exercise. Unloaded and peak PVP were more strongly associated than resting PVP with all adverse outcomes, except reintervention (composite outcome: resting PVP: OR 2.8, p=0.023; unloaded PVP: OR 6.1, p=0.001; peak PVP: OR 4.0, p<0.001). Cut-offs determined using ROC curve analysis had high specificity for the composite outcome (88% unloaded PVP ≥18 mm Hg; 89% peak PVP ≥25 mm Hg).

CONCLUSION

Higher PVP at unloaded and peak exercise was strongly associated with a higher prevalence of adverse Fontan outcomes. Minimally invasive PVP monitoring during CPET may serve as a useful tool for risk stratifying individuals with a Fontan.

Hepatic Steatosis in Patients With Single Ventricle and a Fontan Circulation

Background

Hepatic steatosis, caused by nonalcoholic fatty liver disease, is a leading cause of chronic liver disease. The interplay between hepatic steatosis and the development of liver disease following the Fontan procedure is not well understood. This study examined the prevalence and associations of hepatic steatosis in patients with a Fontan circulation.

Methods and Results

This was a single‐center retrospective study of 95 patients with a Fontan circulation with liver magnetic resonance imaging performed between 2012 and 2019. The average age at magnetic resonance imaging was 21.5±8.5 years. The percent liver fat signal was determined using magnetic resonance chemical shift‐encoded proton density fat fraction imaging. Hepatic steatosis was defined as liver fat ≥5% and was present in 10.5% of the cohort. The presence of hepatic steatosis was associated with higher body mass index (29±4 versus 24±6 kg/m², P=0.006), a higher frequency of obesity (50% versus 12%, P=0.015), lower high‐density lipoprotein cholesterol (35±9 versus 43±14 mg/dL, P=0.050), and greater subcutaneous fat thickness (2.6±0.7 versus 1.8±1.0 cm, P=0.043). There was no association between hepatic steatosis and cardiovascular imaging or hemodynamic variables from cardiac catheterization.

Conclusions

Risk factors for hepatic steatosis in patients with Fontan circulation include obesity and dyslipidemia, similar to what is seen in the general population. Fontan hemodynamics were not associated with hepatic steatosis.

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.

Body Composition and Exercise Performance in Youth With a Fontan Circulation: A Bio-Impedance Based Study

Background Adults with a Fontan circulation tend to have myopenia and elevated adiposity when measured by dual energy x-ray absorptiometry. Bioelectrical impedance analysis is an alternative validated approach to assess body composition. We used bioelectrical impedance analysis to compare body composition between pediatric patients with a Fontan circulation and control individuals without heart disease. Methods and Results A retrospective chart review identified all patients aged <22 years with a Fontan circulation who presented for cardiopulmonary exercise testing and bioelectrical impedance analysis from April 2019 to January 2020. Data were compared with control subjects tested during the same period. We studied 47 patients with a Fontan circulation (53% boys; 15±3.1 years) and 165 controls (48% boys; 14.4±2.5 years). Fontan status was associated with shorter height, but similar age, sex, and overall body mass. Patients with Fontan had lower lean body mass (-12.0±22%, Z-score -0.5±1, P=0.005), skeletal muscle mass (-13.6±1.4%; Z-score, -0.5±1; P=0.004), skeletal muscle indexed to height (-10.3±13.3%; Z-score, -0.5±1; P=0.005), and higher percent body fat (+13.8±18.6%; Z-score, 0.4±1.2; P=0.03). Greater skeletal muscle mass was associated with higher peak oxygen consumption (r2=0.52, P<0.0001) and oxygen pulse (r2=0.68, P<0.0001). Patients who had suffered a late complication (ie, heart transplant referral or evidence of extracardiac organ dysfunction) of the Fontan operation (13 of 47, 27.7%) had lower skeletal muscle mass (P=0.048) and higher body fat percentage (P=0.003). Conclusions The Fontan circulation is associated with marked myopenia and increased adiposity. Higher muscle mass was associated with better exercise capacity. Fontan complications are associated with lower muscle mass and increased adiposity.

Implementation of a Pediatric Chest Pain Local Consensus Guideline Decreases the Total Tests Performed Without Negatively Affecting the Yield of Abnormal Cardiac Results

Pediatric chest pain is common and though usually benign often leads to unnecessary diagnostic testing. There is limited evidence as to whether a local consensus guideline can decrease testing frequency without negatively affecting the overall yield. In addition, it is unknown whether the addition of pulmonary function testing to a cardiopulmonary exercise test increases the diagnostic yield in pediatric patients with chest pain. A retrospective chart review was performed on all new pediatric patients who presented with chest pain at our academic center's pediatric cardiology clinic 18 months before and after the implementation of a standard management guideline. Data from the encounter-associated echocardiogram, cardiopulmonary exercise test, and pulmonary function test, when available, were analyzed. There were no significant differences in patient volume or demographic characteristics in the 18 months before (n = 768) and after (n = 778) guideline implementation. There were significant reductions in the number of ordered echocardiograms (n = 131; 17% vs. n = 75; 9.6%, p < 0.001) and cardiopulmonary exercise tests (n = 46; 6% vs. n = 29; 4%, p = 0.04) with no concerning pathology discovered in either group. Associated pulmonary function testing performed prior to with exercise testing discovered abnormalities in 19% of the total patients tested. The implementation of a local consensus guideline for pediatric chest pain results in fewer unnecessary tests ordered. There was no concerning pathology before or after guideline implementation, therefore conclusions regarding the diagnostic yield of these guidelines are unfeasible. The addition of pulmonary function testing to cardiopulmonary exercise tests increases the potential diagnostic yield in these patients.

Cardiac magnetic resonance derived atrial function in patients with a Fontan circulation

To assess atrial function in Fontan patients using cardiac MRI (CMR) and determine the relationships between atrial function, hemodynamics, and clinical outcomes. Two center chart review identified all Fontan patients with technically adequate CMR to assess atrial function within 1 year of cardiac catheterization and age-matched controls with CMR. Atrial reservoir, conduit, and pump global longitudinal strain and strain rate measurements were determined by CMR. Univariate and stepwise multivariable analysis were conducted to detect associations of atrial function measures with ventricular end diastolic pressure (EDP), cardiac index (CI), exercise capacity, liver stiffness and a composite outcome of heart transplantation, ventricular assist device or death. The study cohort was comprised of 33 Fontan patients and 30 age-matched controls. Fontan patients had lower atrial reservoir and conduit strain, and lower reservoir, conduit, and pump strain rate compared to age-matched controls. Atrial conduit strain was negatively associated with EDP and lower atrial pump-to-conduit strain ratio was associated with lower cardiac index in multivariable analysis. Lower atrial pump strain was associated with lower exercise capacity (per 1% increase: β = 2.3 ± 0.9, p = 0.03) and higher liver stiffness (per 1% increase: β =  - 0.12 ± 0.03, p = 0.002). Higher atrial pump strain (HR per 1% increase = 0.53 [95% confidence interval 0.22, 0.83], p = 0.002) and ventricular ejection fraction (HR per 1% increase = 0.90 [95% confidence interval 0.80, 0.98], p = 0.02) were associated with lower risk for the composite adverse outcome. Atrial function is impaired in Fontan patients and is associated with worse CI, EDP, exercise performance, liver stiffness, and a higher risk for adverse outcomes.

Modified Ventricular Global Function Index Correlates With Exercise Capacity in Repaired Tetralogy of Fallot

Background

Cardiac MRI (CMR) derived ventricular global function index (GFI), a ratio of stroke volume to the sum of mean ventricular cavity and myocardial volumes, has demonstrated improved prediction of clinical outcomes in adults with atherosclerotic disease over ejection fraction. We sought to assess CMR derived GFI and a novel modification that accounts for unique loading conditions in patients with repaired tetralogy of Fallot (rTOF) and determine its correlation with exercise performance.

Methods and Results

Seventy‐five patients with rTOF who underwent CMR were identified. Clinical variables were recorded and biventricular GFI calculated. A right ventricular (RV) effective GFI (eGFI) was derived by incorporating effective stroke volume. Thirty‐five pediatric patients were matched with 29 age‐matched healthy controls. Twenty‐five patients completed cardiopulmonary exercise tests within 6 months of CMR. Stepwise regression models were used to determine univariate and multivariable predictors of indexed and percent predicted peak VO₂. Median age at CMR was 20 years (interquartile range, 13–28). Pediatric rTOF patients had lower RV eGFI (P < 0.001), RV ejection fraction (P=0.002), but higher indexed RV end‐diastolic and end‐systolic volumes (P < 0.001, P < 0.001) compared with controls. Univariate analysis demonstrated a correlation between indexed peak VO₂ with RV eGFI (R²=0.32, P=0.004), but with neither RVGFI, RV ejection fraction, indexed RV volumes nor RV mass. RV eGFI remained significantly associated with indexed peak VO₂ during multivariable modeling.

Conclusions

Reduced RV eGFI was associated with reduced exercise capacity in rTOF patients, while RV GFI, RV ejection fraction, indexed RV volumes and mass were not. Our modification of the GFI, RV eGFI, may be a valuable non‐invasive marker of cardiac function in rTOF.

Left atrial dysfunction in sickle cell anemia is associated with diffuse myocardial fibrosis, increased right ventricular pressure and reduced exercise capacity

Increased extracellular volume (ECV) by CMR is a marker of interstitial myocardial fibrosis and is associated with diastolic dysfunction in sickle cell anemia (SCA). Left atrial (LA) dysfunction and stiffness contribute to the development of diastolic heart failure in other settings. We aimed to evaluate LA function and stiffness associations with ECV, tricuspid regurgitation jet velocity (TRV) and exercise abnormalities in SCA. In a prospective study, individuals with SCA underwent CMR, echocardiography and exercise test. ECV was measured using MOLLI sequence. Atrial strain was studied in the 4- and 2-chamber views. LA stiffness was calculated as the ratio of echocardiographic E/e’-to-LA reservoir strain. Twenty-four participants with SCA were included (median age 20 years). ECV was increased in participant with SCA compared to our lab normal values (mean 0.44 ± 0.08 vs 0.26 ± 0.02, P < 0.0001). Six (25%) had LA LGE. ECV positively correlated with LA stiffness (r = 0.45, p = 0.04). There was a negative correlation between LA stiffness and %predicted VO2 (r = −0.50, p = 0.04). LA stiffness was moderately associated with increased TRV (r = 0.55, p < 0.005). LA stiffness is associated with ECV, exercise impairment and increased TRV. This study sheds insights on the interaction between LA function, RV hypertension, and myocardial fibrosis in SCA.

Reaching the paediatric chest pain audience outside of ambulatory clinic using internet-based education

Paediatric chest pain is common, yet there remain significant barriers to educating and reassuring patients and their families. In July 2014, a blog titled 6 Questions to Ask When Your Child Complains of Chest Pain was posted to the Cincinnati Children's Hospital Medical Center website to help educate children and parents about paediatric chest pain. The enhanced interactions through internet-based resources create the opportunity to address chest pain in a way that both educate and provide reassurance. Through the reassurance, there is the potential to meaningfully reduce patient stress all while also decreasing medical costs and potential medical visits.

Abnormal submaximal cardiopulmonary exercise parameters predict impaired peak exercise performance in sickle cell anemia patients

PURPOSE

Sickle cell anemia (SCA) patients frequently have many comorbidities, including diastolic dysfunction (DD) and exercise intolerance. SCA patients often cannot reach maximal effort on exercise testing; little is known regarding whether submaximal exercise parameters can predict abnormal maximal exercise results in SCA patients and if there are any possible associations with DD.

METHODS

A prospective longitudinal study was performed in SCA patients. All patients had a resting cardiac MRI (CMR), cardiopulmonary exercise test (CPET) with cycle ergometry using a ramp protocol, and an echocardiogram. Exercise data were compared with age-, gender-, and size-matched normal controls.

RESULTS

Compared with normal controls, the SCA group (n = 19) had lower mean max oxygen consumption (VO₂ ; 1378 ± 412 mL/min vs 2237 ± 580, P < 0.01) and workload (117 ± 37.6 watts vs 175 ± 50.5 watts, P = 0.0003). When evaluating the submaximal exercise parameters, there was lower VO₂ at the anaerobic threshold (AT; 950 ± 311.7 vs 1460 ± 409.9, P < 0.01) and oxygen uptake efficiency slope (OUES) at AT (1512 ± 426.2 vs 2080 ± 339, P < 0.01). The max VO₂ strongly correlated with VO₂ at AT (r = 0.9, P < 0.01) and OUES (r = 0.83, P < 0.01) at AT. The VO₂ at AT correlated with hematocrit (r = 0.77, P < 0.05). The OUES correlated with left ventricular ejection fraction by CMR (r = 0.55, P = 0.01), hematocrit (r = 0.52, P = 0.02), and lateral E/e' (r = -0.54, P = 0.01).

CONCLUSIONS

SCA patients have abnormal submaximal exercise measures compared with controls, which is strongly associated with abnormal maximal exercise results. The degree of submaximal abnormality correlates with DD abnormalities by echocardiography. These data expand the scope of functional cardiovascular abnormalities in SCA.

Cardiac morphology for the millennial cardiology fellow: Nomenclature and advances in morphologic imaging

Cardiology fellows-in-training, both in adult and pediatric hospitals, need structured education in regards to congenital heart disease (CHD) nomenclature. With improved survival of patients with CHD, it is not uncommon for these patients to seek care in multiple adult and pediatric hospitals. A deep understanding of CHD nomenclature would aid in providing accurate medical and surgical care for these patients. In this forum, we share our experience with such structured education and also comment on recent advances in morphologic imaging that would aid in understanding the nomenclature.

Cardiopulmonary fitness assessment on maximal and submaximal exercise testing in patients with Fabry disease

The cardiopulmonary exercise test (CPET) is a valuable tool to assess a patient's aerobic fitness and cardiac function, including the response to stress. There have been few studies using CPET to evaluate cardiopulmonary exercise capacity in patients with Fabry disease. We performed a retrospective chart review of patients with Fabry disease from 2001 to 2016, compared to age, gender, and size-matched normal controls. A total of 18 patients were evaluated using the Bruce protocol (treadmill) and 11 patients were evaluated with the ramp protocol (cycle ergometer). The Fabry group demonstrated significantly lower heart rate at peak exercise (151.2 ± 22.5 vs. 178.6 ± 16.2, p < .05), max indexed VO₂ (23.7 ± 7 vs. 33.9 ± 8.4, p < .05), and peak index oxygen pulse (12.1 ± 3 vs. 15.2 ± 4.2, p < .05). When the groups were further separated into treadmill or cycle ergometry testing only, there remained statistically significant differences in peak indexed oxygen pulse, heart rate at peak exercise, and max indexed VO₂ . There was a statistically significant difference between the Fabry patients evaluated by treadmill testing for systolic blood pressure at peak exercise that was not seen in the cycle ergometry group. Additionally, when looking at the patients who had concurrent cardiac MRI (cMRI) with their CPET, there was a positive correlation with max indexed VO₂ and right ventricular end-diastolic volume (r = .55, p = .007) and end-systolic volume (r = .59, p = .007). Patients with Fabry disease have impaired cardiopulmonary exercise capacity as measured by CPET. Additionally, in patients with Fabry disease there is a positive correlation with functional capacity and right ventricular volumes on cMRI.

Diastolic dysfunction is associated with exercise impairment in patients with sickle cell anemia

BACKGROUND

Left ventricular diastolic dysfunction (DD) is an independent risk factor for mortality in sickle cell anemia (SCA) and is associated with increased extracellular volume (ECV) on cardiac MRI (CMR). Exercise impairment is common in SCA, but its causes and prognostic value are not well understood.

OBJECTIVE

To study the effects of DD and ECV on cardiopulmonary exercise test (CPET) in patients with SCA.

METHODS AND RESULTS

As part of a prospective study to characterize the cardiomyopathy of SCA (NCT02410811), 20 children and adults with SCA underwent CMR, echocardiography, and cycle ergometer CPET (age range 8-43 years). Maximum exercise was reached in 18 patients and 17 (94%) had reduced exercise capacity (%predicted VO₂ less than 80%). Six patients had DD and none had systolic dysfunction. Patients with DD had lower exercise capacity compared to patients with normal diastolic function (%predicted VO₂ 48.2 ± 9.1% vs. 61.2 ± 11.7%; P = 0.01). The z-score of left ventricular lateral E/e' ratio, which is a marker of DD, was negatively associated with %predicted VO₂ (r = -0.61, P = 0.01). All patients with moderate-to-severe exercise impairment (%predicted VO₂  < 60%) had lateral E/e' z-score > 2. In a multivariate analysis, lateral E/e' z-score was independently associated with %predicted VO₂ (P = 0.02). All participants had elevated ECV but the degree of elevation was not associated with exercise parameters.

CONCLUSION

Left ventricular DD is associated with decreased exercise capacity in SCA. Interventions to prevent or delay DD could improve exercise capacity, quality of life, and long-term outcomes in SCA.

Widespread Vasculopathy in a Patient with Morquio A Syndrome

Morquio A syndrome (mucopolysaccharidosis IV type A), an autosomal recessive lysosomal storage disorder caused by a defective N-acetylgalactosamine 6-sulfatase gene, leads to lysosomal accumulation of keratan sulfate and chondroitin 6-sulfate. This accumulation affects multiple systems and causes notable cardiovascular manifestations, such as thickening of the left-sided valves, ventricular hypertrophy, and intimal stenosis of the coronary arteries. There have been few reports of vasculopathy in this population. We present the case of a 58-year-old woman with Morquio A syndrome who was found to have aortic dilation on a routine screening echocardiogram. Magnetic resonance images revealed multiple tortuous, dilated arteries in her head, neck, and abdomen. The diffuse vasculopathy seen in this patient should prompt further study to determine whether this is an underreported phenomenon of clinical significance or an unusual finding in this rare disorder.