Healthy hearts in pediatric heart transplant patients with an exercise and diet intervention via live video conferencing-Design and rationale.

BACKGROUND: Pediatric heart transplant (PedHtx) patients have increased cardiovascular risk profiles that affect their long-term outcomes and quality of life. We designed a 12- to 16-week diet and exercise intervention delivered via live video conferencing to improve cardiovascular health. Our methodology and baseline assessment of the first 13 enrolled patients are reported. METHODS: Inclusion criteria are as follows: (a) 8-19 years old; (b) heart transplant >12 months; (c) ability to fast overnight; (d) cardiac clearance by cardiologist; and (e) presence of an adult at home during exercise sessions for patients <14 years old. Exclusion criteria are as follows: (a) acute illness; (b) latex allergy; (c) transplant rejection <3 months ago; and (d) multi-organ transplantation. The intervention consists of one diet and three exercise sessions weekly via live video conferencing. Study visits are conducted at baseline, intervention completion, and end of maintenance period. RESULTS: A total of 13 participants (15.2 [2.3] years) have been enrolled. Median percent-predicted VO2 max was 56.8 [20.7]% (10 patients <70%). Ten patients had abnormal endothelial function (reactive hyperemia index <1.9; 1.4 [0.325]) and 11 patients had stiff arteries (pulse wave velocity ≧5.5 m/s for 15-19 years, ≧4.5 m/s for 8-14 years; 5.6 [0.7] m/s). Patients had suboptimal diets (saturated fat: 22.7 [23.8] g/d, sodium: 2771 [1557] mg/d) and were sedentary at a median of 67.5 [13.8]% of their time. CONCLUSIONS: Baseline assessment confirms that PedHtx patients have abnormal cardiac, vascular, and functional health indices, poor dietary habits, and are sedentary. These results support the rationale to test the feasibility and impact of a non-pharmacologic lifestyle intervention in this patient population.

Live Video Diet and Exercise Intervention in Overweight and Obese Youth: Adherence and Cardiovascular Health.

OBJECTIVE: To evaluate adherence of overweight and obese adolescents to a live video lifestyle intervention. The impact on vascular and functional health was also assessed. STUDY DESIGN: Twenty adolescents 14.5 ± 2.1 years of age with body mass index z-score 1.94 ± 0.43 were enrolled. The 12-week intervention included 3-times-weekly videoconference sessions with a trainer and weekly diet consultations. Adherence was evaluated by completion rate and percentage of sessions attended. Vascular health indices and traditional cardiovascular risk factors were obtained at baseline and study end. RESULTS: Seventeen participants (85%) completed the intervention. The participants attended 93 ± 11% of scheduled sessions. Reasons for absences included illness/injury (23%), school activities (21%), holidays (18%), forgetting the appointment (8%), Internet connectivity issues (7%), and family emergency (7%). Significant changes were observed in waist-hip ratio (0.87 ± 0.08 vs 0.84 ± 0.08, P = .03), total (159 ± 27 vs 147 ± 23 mg/dL, P = .004) and low-density lipoprotein cholesterol levels (91 ± 20 vs 81 ± 18 mg/dL, P = .004), volume of inspired oxygen per heartbeat at peak exercise (69 ± 16 vs 72 ± 15%, P = .01), and functional movement score (13 ± 2 vs 17 ± 1, P < .001). Participants with abnormal vascular function at baseline showed improvement in endothelial function and arterial stiffness indices (P = .01 and P = .04, respectively). CONCLUSIONS: A 12-week live video intervention promotes adherence among overweight and obese adolescents and shows promise for improving vascular and functional health. Integrating telehealth into preventive care has the potential to improve cardiovascular health in the youth at risk.

Supine cycling in pediatric exercise testing: disparity in performance measures.

Supine cycling may be an important alternative modality for exercise testing. Subtle differences in supine and upright exercise physiology have been suggested but not fully explored in the pediatric population. The aim of this study was to compare peak and submaximal metabolic data in the upright and supine exercise positions. Healthy children (N = 100) performed cardiopulmonary exercise tests using supine and upright cycle ergometry. Recruitment was governed by grant funding and not based on sample size calculations. Subjects exercised to exhaustion. Paired Student's t-tests were used to compare upright and supine data; simple linear regression analyses examined correlations between the two modalities. Peak heart rate was similar in both testing positions. Although peak oxygen uptake (peak VO2), oxygen uptake at anaerobic threshold (VO2@AT), VO2 when the respiratory exchange ratio is consistently at or above 1.0 (VO2@RER1.0), and the oxygen uptake efficiency slope were significantly higher in the upright position, no difference was considered of practical significance when applying Cohen's effect size criteria. Therefore, it may be reasonable for pediatric exercise laboratories to use established normative data and predictions for upright cycling position and apply them to metabolic measures obtained in supine exercise testing. Supine cycling with submaximal parameters may allow objective assessment of exercise capacity in children who undergo exercise echocardiography or cannot perform upright exercise testing.

VO2@RER1.0: a novel submaximal cardiopulmonary exercise index.

Maximal oxygen consumption (VO2max) is the "gold standard" by which to assess functional capacity; however, it is effort dependent. VO2@RER1.0 is defined when VO2 = VCO2. Between December 22, 1997 and November 9, 2004, 305 pediatric subjects underwent cycle ergometer cardiopulmonary exercise testing, exercised to exhaustion, and reached a peak respiratory exchange ratio > or = 1.10. Group 1 subjects achieved a peak VO2 > or = 80% of predicted VO2max; group 2 subjects achieved a peak VO2 < or = 60% of predicted VO2max; and group 3 subjects achieved a peak VO2 between 61 and 79% of predicted VO2max. Linear regression analysis was performed for VO2@RER1.0 as a function of predicted VO2 for group 1 subjects. A -2 SD regression line and equation was created. VO2@RER1.0 data from groups 2 and 3 were plotted onto the normative graph. Contingency table and relative-risk analysis showed that an abnormal VO2@RER1.0 predicted an abnormal peak VO2(positive-predictive value 83%, negative-predictive value 85%, sensitivity 84%, and specificity 84%). VO2@RER1.0 is a highly sensitive, specific, and predictive submaximal index of functional capacity. This submaximal index is easy to identify without subjectivity. This index may aid in the evaluation of subjects who cannot exercise to maximal parameters.

Correlation of subjective questionnaires with cardiac function as determined by exercise testing in a pediatric population.

BACKGROUND: Although exercise testing is an important objective method used to assess cardiopulmonary function, subjective assessment often is used as a proxy in the clinical setting. This study aimed to determine whether responses to a subjective functional capacity questionnaire administered to parents and patients in a pediatric exercise laboratory correlate with objective assessment of functional capacity, measured by peak oxygen consumption during maximal voluntary exercise testing. METHODS: Subjective questionnaire responses and exercise test results collected over 10 years were retrospectively analyzed. Symptoms and physical capabilities were assessed using a 6-point Likert scale regarding the ability to attend school/work, walk, climb stairs, and run, as well as the frequency of fatigue, palpitations, and chest pain. Values of 0 to 3 were considered abnormal, whereas values of 4-5 were regarded as normal. Exercise testing was performed on a stationary cycle ergometer with a continuous ramping protocol. Heart rate and oxygen saturation were continuously monitored. Blood pressures and electrocardiograms (ECGs) were obtained at 2-min intervals. Metabolic gas analysis was performed using a breath-by-breath method. The results of the exercise testing were normalized for body size and expressed as a percentage of predicted peak oxygen consumption (%pVO(2)). RESULTS: Very weak but statistically significant correlations (τ < 0.25; P < 0.05) between the scores of the school/work, walking, stair climbing, running, and fatigue items and %pVO(2) were found using Kendall's rank correlations. CONCLUSIONS: The subjective Likert scales used to assess basic physical capacity and cardiac-associated symptoms have limited ability to predict actual functional capacity as measured by %pVO(2) achieved. The very weak rank-order correlation between %pVO(2) achieved and the subjective reporting of the ability to attend school/work, walk, climb stairs, and run has low clinical significance and will not be useful in predicting functional capacity within the clinic setting.

Healthy Hearts via Live Videoconferencing: An Exercise and Diet Intervention in Pediatric Heart Transplant Recipients.

Background Pediatric heart transplant recipients have high-risk cardiovascular profiles that can affect their long-term outcomes; however, promoting exercise and healthy diet has not been a major focus in the field. The objective of this study was to test the feasibility and impact of a supervised exercise and diet intervention delivered via live videoconferencing in this population. Methods and Results Patients 8 to 19 years of age at least 1 year post heart transplantation were enrolled. The 12- to 16-week intervention phase included live video-supervised exercise (×3/week) and nutrition (×1/week) sessions. The 12- to 16-week maintenance phase included ×1/week live video-supervised exercise and nutrition sessions and ×2/week self-directed exercise sessions. Cardiac, vascular, nutritional, and functional health indices were obtained at baseline, after intervention, and after maintenance. Fourteen patients (median age, 15.2; interquartile range, 14.3-16.7 years) at a median of 3.3 (interquartile range, 1.5-9.7) years after heart transplant completed the intervention. Patients attended 89.6±11% of exercise and 88.4±10% of nutrition sessions during the intervention and 93.4±11% of exercise and 92.3±11% of nutrition sessions during maintenance. After intervention, body mass index percentile (median, -27%; P=0.02), endothelial function (median, +0.29; P=0.04), maximum oxygen consumption (median, +2 mL/kg per minute; P=0.002). Functional Movement Screening total score (median, +2.5; P=0.002) and daily consumption of saturated fat (median, -6 g; P=0.02) improved significantly. After maintenance, improvements in maximum oxygen consumption (median, +3.2 mL/kg per minute; P=0.02) and Functional Movement Screening total score (median, +5; P=0.002) were sustained. Conclusions In pediatric heart transplant recipients, a live video-supervised exercise and diet intervention is feasible. Our results demonstrate excellent adherence with significant improvements in cardiovascular and functional health. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02519946.

Diminished exercise capacity and chronotropic incompetence in pediatric patients with congenital complete heart block and chronic right ventricular pacing.

BACKGROUND: Chronic right ventricular (RV) pacing has been associated with decreased exercise capacity and left ventricular (LV) function in adults with congenital complete atrioventricular block (CCAVB), but not in children. OBJECTIVE: The purpose of this study was to evaluate the exercise capacity and LV function in pediatric patients with CCAVB receiving chronic RV pacing. METHODS: We prospectively evaluated pediatric patients with isolated CCAVB receiving atrial synchronous RV pacing for at least 5 years. Supine bicycle ergometry was performed, and LV ejection fraction (EF) was evaluated by echocardiography. RESULTS: Ten CCAVB subjects and 31 controls were matched for age, gender, and body surface area. CCAVB subjects had normal resting EF (63.1% ± 4.0%) and had been paced for 7.9 ± 1.4 years. Exercise testing demonstrated reduced functional capacity in CCAVB patients compared to controls with a lower VO2peak (26.0 ± 6.6 mL/kg/min vs 39.9 ± 7.0 mL/kg/min, P <.001), anaerobic threshold (15.6 ± 3.9 mL/kg/min vs 18.8 ± 2.7 mL/kg/min, P = .007), and oxygen uptake efficiency slope (1210 ± 406 vs 1841 ± 452, P <.001). Maximum heart rate (165 ± 8 bpm vs 185 ± 9 bpm, P <.001) and systolic blood pressure (159 ± 17 mm Hg vs 185 ± 12 mm Hg, P <.019) also were reduced in CCAVB patients despite maximal effort (respiratory exchange ratio 1.2 ± 0.1). EF was augmented with exercise in controls but not in CCAVB patients (13.2% ± 9.3% vs 0.2% ± 4.8% increase, P <.001). CONCLUSION: Clinically asymptomatic children with chronic RV pacing due to CCAVB have significant reductions in functional capacity accompanied by chronotropic incompetence and inability to augment EF with exercise.

Supine exercise echocardiographic measures of systolic and diastolic function in children.

BACKGROUND: Echocardiography has been used to determine ventricular function, segmental wall motion abnormality, and pulmonary artery pressure before and after peak exercise. No prior study has investigated systolic and diastolic function using echocardiography at various phases of exercise in children. The aim of this study was to determine the fractional shortening (FS), systolic-to-diastolic (S/D) ratio, heart rate-corrected velocity of circumferential fiber shortening (VCFc), circumferential wall stress (WS), ratio of mitral passive inflow to active inflow (E/A), ratio of passive inflow by pulsed-wave to tissue Doppler (E/E'), and right ventricular-to-right atrial pressure gradient from tricuspid valve regurgitation jet velocity (RVP) and time duration at various phases of exercise in children. METHODS: In an 8-month period (December 2007 to July 2008), 100 healthy children were evaluated, and 97 participants aged 8 to 17 years who performed complete cardiopulmonary exercise stress tests using supine cycle ergometry were prospectively enrolled. The participants consisted of 48 female and 49 male subjects with various body sizes, levels of exercise experience, and physical capacities. The cardiopulmonary exercise stress test consisted of baseline pulmonary function testing, continuous gas analysis and monitoring of blood pressure and heart rate responses, electrocardiographic recordings, and oxygen saturation measurement among participants who pedaled against a ramp protocol based on body weight. All participants exercised to exhaustion. Echocardiography was performed during exercise at baseline, at a heart rate of 130 beats/min, at a heart rate of 160 beats/min, at 5 min after exercise, and at 10 min after exercise. FS, S/D ratio, VCFc, WS, E/A, E', E/E', and RVP at these five phases were compared in all subjects. RESULTS: All echocardiographic parameters differed at baseline from 160 beats/min (P < .0001) except E/E', which remained at 5.4 to 5.8. Specifically, FS (from 37% to 46%), S/D ratio, VCFc (from 1.1 to 1.6), WS (from 200 to 258 g/cm(2)), E' (from 0.2 to 0.3), and RVP (from 18 to 35 mm Hg) increased from baseline to 160 beats/min and then subsequently decreased to at or near baseline, while tricuspid valve regurgitation duration decreased (from 370 to 178 msec). CONCLUSIONS: Normal values for systolic and diastolic echocardiographic measurements of function are now available. FS, VCFc, WS, and RVP increase with exercise and then return to near baseline levels. The E/E' ratio is unaltered with exercise in normal subjects.