Heart rate variability is reduced in COVID-19 survivors and associated with physical activity and fatigue.

Reduced heart rate variability (HRV) and fatigue are common after COVID-19 infection and both are potentially influenced by physical activity (PA). We compared resting HRV, PA from accelerometers and questionnaires, and self-reported fatigue in 41 COVID-19 survivors (~8 months postinfection, 38 ± 17 years) with 41 matched controls. Differences in HRV were observed on acceleration capacity (p = 0.041), deceleration capacity (p = 0.032), high-frequency peak frequency (p = 0.019), absolute low-frequency power (p = 0.042), relative very low-frequency power (p = 0.012), SD2 (from Poincare plot; p = 0.047), and DFA2 (slope of long-term detrended fluctuation analysis; p = 0.004). Fatigue was greater in COVID-19 survivors (p < 0.001) with no differences in PA. Moderate-vigorous physical activity (MVPA) (Standardized Beta = -0.427, p = 0.003) and steps per day (Standardized Beta = -0.402, p = 0.007) were associated with DFA2 in COVID-19 survivors after controlling for age, sex, and body fat percentage. Fatigue was correlated to less MVPA (Spearman's rho = 0.342, p = 0.031) and fewer steps per day (rho = 0.329, p = 0.038) in COVID-19 survivors, and was indirectly linked to HRV through these PA mediators (Estimate = -0.20; p = 0.040). We present a model showing the complex relations between HRV, PA, and fatigue that provides the foundation for strategies to improve outcomes and rehabilitation after COVID-19 infection.

Impact of a paediatric cardiac rehabilitation programme upon patient quality of life.

INTRODUCTION: Cardiac rehabilitation programmes for paediatric patients with congenital heart disease (CHD) have been shown to promote emotional and physical health without any associated adverse events. While prior studies have demonstrated the effectiveness of these types of interventions, there has been limited research into how the inclusion of psychological interventions as part of the programme impacts parent-reported and patient-reported quality of life. MATERIALS AND METHODS: Patients between the ages of 7 and 24 years with CHD completed a cardiac rehabilitation programme that followed a flexible structure of four in person-visits with various multidisciplinary team members, including paediatric psychologists. Changes in scores from the earliest to the latest session were assessed regarding exercise capacity, patient functioning (social, emotional, school, psychosocial), patient general and cardiac-related quality of life, patient self-concept, and patient behavioural/emotional problems. RESULTS: From their baseline to final session, patients exhibited significant improvement in exercise capacity (p = 0.00009). Parents reported improvement in the patient's emotional functioning, social functioning, school functioning, psychosocial functioning, cognitive functioning, communication, and overall quality of life. While patients did not report improvement in these above areas, they did report perceived improvement in certain aspects of cardiac-related quality of life and self-concept. DISCUSSION: This paediatric cardiac rehabilitation programme, which included regular consultations with paediatric psychologists, was associated with divergent perceptions by parents and patients on improvement related to quality of life and other aspects of functioning despite improvement in exercise capacity. Further investigation is recommended to identify underlying factors associated with the differing perceptions of parents and patients.

Quantifying Activity Levels After Sport-Related Concussion Using Actigraph and Mobile (mHealth) Technologies.

CONTEXT: Interest in identifying the effects of physical and mental activity on recovery after sport-related concussion is growing. Clinical studies of concussed athletes' activities require well-validated methods for tracking their intensity and timing. OBJECTIVE: To develop and validate a novel multimodal approach to monitoring activity postconcussion using mobile (mHealth) technologies. DESIGN: Cohort study. SETTING: Translational research unit. PATIENTS OR OTHER PARTICIPANTS: A total of 40 high school and collegiate football players were evaluated at preseason and followed longitudinally after either concussion (n = 25; age = 17.88 ± 1.74 years, height = 182.07 ± 8.08 cm, mass = 98.36 ± 21.70 kg) or selection as a nonconcussed control (n = 15; age = 18.27 ± 1.83 years, height = 180.01 ± 7.19 cm, mass = 93.83 ± 24.56 kg). MAIN OUTCOME MEASURE(S): Participants wore a commercial actigraph and completed a daily mobile survey for 2 weeks. Analyses focused on comparisons between groups for actigraph-based physical activity and self-reported physical and mental activity during the follow-up period. RESULTS: For the first 2 days postinjury, objective measures showed fewer daily steps in concussed (6663 ± 2667 steps) than in control (11 148 ± 3381 steps) athletes (P < .001), and both objective and self-reported measures indicated less moderate to vigorous physical activity in concussed (27.6 ± 32.6 min/d and 25.0 ± 43.6 min/d, respectively) than in control (57.3 ± 38.6 min/d and 67.5 ± 40.1 min/d, respectively) athletes (both P values < .05). Correlations between objective and self-reported measures of moderate to vigorous physical activity were moderate across select 1-week and 2-week averages. We observed no group differences in self-reported mental activities. CONCLUSIONS: Physical activity after sport-related concussion varied widely across athletes but on average was reduced during the acute and early subacute postinjury periods for both objective and self-reported measures. The lack of differences in mental activities between groups may reflect limited change in mental exertion postconcussion or difficulty accurately measuring mental activities. Assessing concussed athletes' activities using actigraphy and self-reported scales may help monitor their compliance with activity recommendations and be useful in studies aimed at better understanding the effects of physical activity on concussion recovery.

Intrauterine growth restriction is not associated with decreased exercise capacity in adolescents with congenital heart disease.

OBJECTIVE: Multiple studies demonstrate the association of intrauterine growth restriction (IUGR) with impaired aerobic fitness in adolescents and adults. To our knowledge, there are no studies including individuals with the history of both IUGR and congenital heart disease (CHD). Thus, we sought to evaluate the impact of IUGR on exercise capacity in adolescents with CHD. STUDY DESIGN: We conducted a retrospective chart review of patients <18 years of age who underwent cardiopulmonary exercise testing (CPET) between August 1, 2003 and July 1, 2016. Individuals with birth weight <10th percentile for gestational age were defined as IUGR. Patients with IUGR were matched with non-IUGR patients by cardiac diagnosis and age at CPET. We excluded patients >18 years of age at time of CPET, those without a documented birth weight, gestational age, or Race. RESULTS: A total of 282 patients were included with CHD present in 86 IUGR cases and 86 controls. There was no difference in percent predicted exercise duration (IUGR: 65.2% ± 31.2, non-IUGR: 67.4% ± 27.2; P = .67). Resting heart rate, chronotropic index, percent-predicted peak oxygen consumption, and pulmonary function were similar between groups. Regression analyses confirmed that IUGR was not independently associated with difference in percent-predicted exercise duration. CONCLUSIONS: Intrauterine growth restriction is not associated with the differences in the measurements of exercise capacity in adolescents with CHD. These findings contrast earlier studies, showing decreased fitness in individuals with low birth weight but without CHD. To our knowledge, this is the first study to examine the impact of IUGR on exercise capacity in patients with CHD.

Toward translating near-infrared spectroscopy oxygen saturation data for the non-invasive prediction of spatial and temporal hemodynamics during exercise.

Image-based computational fluid dynamics (CFD) studies conducted at rest have shown that atherosclerotic plaque in the thoracic aorta (TA) correlates with adverse wall shear stress (WSS), but there is a paucity of such data under elevated flow conditions. We developed a pedaling exercise protocol to obtain phase contrast magnetic resonance imaging (PC-MRI) blood flow measurements in the TA and brachiocephalic arteries during three-tiered supine pedaling at 130, 150, and 170 % of resting heart rate (HR), and relate these measurements to non-invasive tissue oxygen saturation [Formula: see text] acquired by near-infrared spectroscopy (NIRS) while conducting the same protocol. Local quantification of WSS indices by CFD revealed low time-averaged WSS on the outer curvature of the ascending aorta and the inner curvature of the descending aorta (dAo) that progressively increased with exercise, but that remained low on the anterior surface of brachiocephalic arteries. High oscillatory WSS observed on the inner curvature of the aorta persisted during exercise as well. Results suggest locally continuous exposure to potentially deleterious indices of WSS despite benefits of exercise. Linear relationships between flow distributions and tissue oxygen extraction calculated from [Formula: see text] were found between the left common carotid versus cerebral tissue [Formula: see text] and the dAo versus leg tissue [Formula: see text]. A resulting six-step procedure is presented to use NIRS data as a surrogate for exercise PC-MRI when setting boundary conditions for future CFD studies of the TA under simulated exercise conditions. Relationships and ensemble-averaged PC-MRI inflow waveforms are provided in an online repository for this purpose.

Cardiopulmonary Exercise Testing in Fontan Patients With and Without Isomerism (Heterotaxy) as Compared to Patients With Primary Ciliary Dyskinesia and Subjects With Structurally Normal Hearts.

Isomerism, also known as heterotaxy, is a clinical entity that impacts multiple organ systems both anatomically and functionally. The airways and lungs are involved in a great number of these patients, leading to increased sinopulmonary symptoms, increased need for oxygenation, and increased postoperative ventilatory support. Additionally, these patients often have congenital heart disease requiring Fontan palliation. What has not been previously described, and is the focus of this study, is the results of cardiopulmonary exercise testing in those who have undergone Fontan palliation with and without isomerism. We have now compared these finding with those from patients with primary ciliary dyskinesia, as many patients with isomerism have ciliary dyskinesia. We identified patients having the Fontan circulation with and without isomerism who had undergone cardiopulmonary exercise testing, comparing the findings from healthy individuals undergoing exercise, and a comparable number of individuals with primary ciliary dyskinesia but no congenital heart disease. We were able to include a total of 68 patients in our study, with 17 in each of the four groups. Cardiopulmonary exercise testing yielded the best results in healthy patients. All patients with the Fontan circulation demonstrated mixed pulmonary disease, although those with isomerism had greater FVC and FEV1. Exercise times did not differ, although peak consumption of oxygen was greater in those with isomerism. Those with ciliary dyskinesia had only obstructive pulmonary disease and had the lowest FEF25-75 between all groups. Those with isomerism had a lesser degree of obstructive pulmonary disease when compared to those with primary ciliary dyskinesia. Patients with the Fontan circulation with and without isomerism have relatively subtle differences in their cardiopulmonary exercise testing, with both groups demonstrating restrictive lung disease. In regard to obstructive lung disease, those with isomerism tend to be more similar to the patients with primary ciliary dyskinesia than those with the Fontan circulation but without isomerism. The results are likely limited by selection bias and highlight the need for multicentric efforts to characterize cardiopulmonary exercise testing in those patients with pulmonary isomerism.

Can a Home-based Cardiac Physical Activity Program Improve the Physical Function Quality of Life in Children with Fontan Circulation?

OBJECTIVE: Patients after Fontan operation for complex congenital heart disease (CHD) have decreased exercise capacity and report reduced health-related quality of life (HRQOL). Studies suggest hospital-based cardiac physical activity programs can improve HRQOL and exercise capacity in patients with CHD; however, these programs have variable adherence rates. The impact of a home-based cardiac physical activity program in Fontan survivors is unclear. This pilot study evaluated the safety, feasibility, and benefits of an innovative home-based physical activity program on HRQOL in Fontan patients. METHODS: A total of 14 children, 8-12 years, with Fontan circulation enrolled in a 12-week moderate/high intensity home-based cardiac physical activity program, which included a home exercise routine and 3 formalized in-person exercise sessions at 0, 6, and 12 weeks. Subjects and parents completed validated questionnaires to assess HRQOL. The Shuttle Test Run was used to measure exercise capacity. A Fitbit Flex Activity Monitor was used to assess adherence to the home activity program. RESULTS: Of the 14 patients, 57% were male and 36% had a dominant left ventricle. Overall, 93% completed the program. There were no adverse events. Parents reported significant improvement in their child's overall HRQOL (P < .01), physical function (P < .01), school function (P = .01), and psychosocial function (P < .01). Patients reported no improvement in HRQOL. Exercise capacity, measured by total shuttles and exercise time in the Shuttle Test Run and calculated VO2 max, improved progressively from baseline to the 6 and 12 week follow up sessions. Monthly Fitbit data suggested adherence to the program. CONCLUSION: This 12-week home-based cardiac physical activity program is safe and feasible in preteen Fontan patients. Parent proxy-reported HRQOL and objective measures of exercise capacity significantly improved. A 6-month follow up session is scheduled to assess sustainability. A larger study is needed to determine the applicability and reproducibility of these findings in other age groups and forms of complex CHD.

Pain Response after Maximal Aerobic Exercise in Adolescents across Weight Status.

INTRODUCTION: Pain reports are greater with increasing weight status, and exercise can reduce pain perception. It is unknown, however, whether exercise can relieve pain in adolescents of varying weight status. The purpose of this study was to determine whether adolescents across weight status report pain relief after high-intensity aerobic exercise (exercise-induced hypoalgesia (EIH)). METHODS: Sixty-two adolescents (15.1 ± 1.8 yr, 29 males) participated in the following three sessions: 1) pressure pain thresholds (PPT) before and after quiet rest, clinical pain (McGill Pain Questionnaire), and physical activity levels (self-report and ActiSleep Plus Monitors) were measured, 2) PPT were measured with a computerized algometer at the fourth finger's nailbed, middle deltoid muscle, and quadriceps muscle before and after maximal oxygen uptake test (V˙O2max Bruce Treadmill Protocol), and 3) body composition was measured with dual-energy x-ray absorptiometry. RESULTS: All adolescents met criteria for V˙O2max. On the basis of body mass index z-score, adolescents were categorized as having normal weight (n = 33) or being overweight/obese (n = 29). PPT increased after exercise (EIH) and were unchanged with quiet rest (trial × session, P = 0.02). EIH was similar across the three sites and between normal-weight and overweight/obese adolescents. Physical activity and clinical pain were not correlated with EIH. Overweight/obese adolescents had similar absolute V˙O2max (L·min(-1)) but lower relative V˙O2max (mL·kg(-1)·min(-1)) compared with normal-weight adolescents. When adolescents were categorized using FitnessGram standards as unfit (n = 15) and fit (n = 46), the EIH response was similar between fitness levels. CONCLUSIONS: This study is the first to establish that both overweight and normal-weight adolescents experience EIH. EIH after high-intensity aerobic exercise was robust in adolescents regardless of weight status and not influenced by physical fitness.

Effect of Fontan fenestration on regional venous oxygen saturation during exercise: further insights into Fontan fenestration closure.

Fontan fenestration closure is a topic of great debate. The body of data regarding the risks and benefits of fenestration closure is limited yet growing. Previous studies have demonstrated that Fontan patients have less exercise capacity than those with normal cardiovascular anatomy. Differences also have been noted within various subgroups of Fontan patients such as whether Fontan is fenestrated or not. This study aimed to compare trends in regional oxygen saturations using near-infrared spectroscopy (NIRS) in patients with Fontan circulations during ramping exercise to further delineate differences between patients with and without a fenestration. It was hypothesized that Fontan patients with fenestrations have better exercise times, higher absolute regional oxygen venous saturations, and smaller arteriovenous differences than Fontan patients without fenestrations. For this study, 50 consecutive Fontan patients and 51 consecutive patients with normal cardiovascular anatomy were recruited. Placement of NIRS probes was performed to obtain regional oxygen saturations from the brain and the kidney. Readings were obtained at 1-min intervals during rest, exercise, and recovery. A standard Bruce protocol was used with a 5-min recovery period. Absolute regional tissue oxygenation values (rSO2) and arterial-venous oxygen saturation differences (AVDO2) calculated as arterial oxygen saturation (SPO2)--rSO2 for normal versus Fontan patients and for fenestrated versus unfenestrated Fontan patients were compared using independent t tests. When normal and Fontan patients were compared, the Fontan patients had a significantly shorter duration of exercise (9.3 vs 13.2 min; p < 0.001). No statistically significant difference in rSO2 change or AVDO2 was evident at the time of peak exercise, at 2 min into the recovery, or at 5 min into the recovery. A small oxygen debt also was paid back to the brain in the Fontan patients after exercise, as evidenced by a narrower AVDO2 than at baseline. The comparison of Fontan patients with and without fenestration showed no statistically significant difference in exercise time, rSO2 change, or AVDO2. The Fontan patients were noted to have shorter exercise times than the normal patients and also appeared to have an alteration in postexertional regional blood flow. However, when the various Fontan subtypes were compared by presence or absence of a fenestration, no significant differences were noted with regard to change in regional oxygen saturation or arteriovenous oxygen saturation. Thus, for patients with Fontan physiology, closure of the fenestration does not seem to have an impact on the dynamics of regional oxygen extraction during exercise or recovery.

Restrictive versus nonrestrictive physiology following repair of tetralogy of Fallot: is there a difference?

BACKGROUND: Long-term outcome in repaired tetralogy of Fallot (TOF) is related to chronic pulmonary insufficiency (PI), right ventricular (RV) dilation, and deterioration of RV function. The aim of this study was to characterize clinical differences between restrictive and nonrestrictive RV physiology in young patients with repaired TOF. METHODS: Patients were prospectively enrolled from February 2008 to August 2009. Each had a clinic visit, brain natriuretic peptide assessment, exercise test, cardiac magnetic resonance study, and echocardiographic examination with assessment of regional myocardial mechanics. Consistent antegrade diastolic pulmonary arterial flow with atrial contraction identified restrictive RV physiology. RESULTS: Twenty-nine patients (median age, 12 years; range, 8-33 years; nine male patients) were studied. Twelve had restrictive RV physiology. The median time since initial TOF repair was 12 years (range, 5-27 years). Restrictive physiology appeared more prevalent after transannular patch repair and was not influenced by other demographic features. The restrictive group had more PI (46% vs 28%, P = .002), larger RV end-diastolic volumes (128 vs 98 mL/m(2), P = .046), but similar ejection fractions, brain natriuretic peptide levels, New York Heart Association classes, and exercise capacity. RV basal and mid free wall peak diastolic strain rate differed between groups, negatively correlating with exercise time and positively correlating with PI in patients with restrictive physiology. CONCLUSIONS: Restrictive RV physiology correlates with a larger right ventricle and increased PI after TOF repair but does not negatively affect other markers of myocardial health. Diastolic regional RV myocardial mechanics, particularly diastolic velocity and peak diastolic strain rate, differ for postoperative TOF patients with restrictive and nonrestrictive RV physiology; longitudinal study is necessary to understand the relationship of regional myocardial mechanics and patients' clinical status.

Restrictive lung disease is an independent predictor of exercise intolerance in the adult with congenital heart disease.

BACKGROUND/OBJECTIVES: Following repair of congenital heart disease (CHD), adult patients are at risk for reduced exercise capacity. Restrictive lung disease (RLD) may contribute to reduced exercise capacity in this population. The aim of this study was to determine the prevalence of RLD and its impact on exercise tolerance in the adult with CHD. METHODS: One hundred consecutive adult patients with CHD, who underwent routine cardiopulmonary exercise testing with spirometry, were evaluated. Clinical data were obtained by retrospective chart review. RESULTS: Patients from 10 major diagnostic groups were identified. The median age for the cohort was 31 years (range 18-63) and included 43 males and 57 females. Most patients, 79%, had at least one previous surgical procedure. Based on spirometry and flow/volume loops, 50 patients were classified as normal pulmonary function, 44 patients had patterns suggestive of RLD, 4 suggestive of mixed (obstructive and restrictive), and 2 indeterminate. Risk factors associated with RLD include history of multiple thoracotomies (odds ratio = 9.01, P =.05) and history of atrial arrhythmias (odd ratio = 4.25, P =.05). Overall, 56% of the patients had abnormal exercise capacity. Spirometry suggestive of RLD was a significant risk factor for decreased exercise capacity (odds ratio = 3.65, P =.03). Patients with spirometry suggesting RLD also had lower exercise duration (P =.004) and a higher New York Heart Association Functional Class (P =.02). History of previous surgery and decreased heart rate reserve were also significant risk factors for decreased exercise capacity. CONCLUSION: Abnormal spirometry suggestive of RLD is common in the adult with CHD and is a significant risk factor for decreased exercise tolerance in this population. Further studies are needed to evaluate the relationship between RLD and exercise intolerance and its relationship to mortality in the adult with CHD.

Near-infrared spectroscopic monitoring during cardiopulmonary exercise testing detects anaerobic threshold.

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 [Formula: see text] 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.

Near infrared spectroscopy describes physiologic payback associated with excess postexercise oxygen consumption in healthy controls and children with complex congenital heart disease.

Exercise creates a physiologic burden with recovery from such effort crucial to adaptation. Excess postexercise oxygen consumption (EPOC) refers to the body's increased metabolic need after work. This investigation was designed to determine the role of near infrared spectroscopy (NIRS) in the description of exercise recovery in healthy controls (NL) and children with congenital heart disease (CHD). Subjects were recruited with exercise testing performed to exhaustion. Exercise time (EXT), heart rate (HR), and oxygen consumption (VO(2)) were measured. Four-site NIRS (brain, kidney, deltoid, and vastus lateralis) were measured during exercise and into recovery to establish trends. Fifty individuals were recruited for each group (NL = 26 boys and 24 girls; CHD = 33 boys and 17 girls). Significant differences existed between EXT, VO(2), and peak HR (P < 0.01). NIRS values were examined at four distinct intervals: rest, peak work, and 2 and 5 min after exercise. Significant cerebral hyperemia was seen in children with CHD post exercise when compared to normal individuals in whom redistribution patterns were directed to somatic muscles. These identified trends support an immediate compensation of organ systems to re-establish homeostasis in peripheral beds through enhanced perfusion. Noninvasive NIRS monitoring helps delineate patterns of redistribution associated with EPOC in healthy adolescents and children with CHD.

Objectively assessed physical activity and sedentary behaviour does not differ between children and adolescents with and without a congenital heart defect: a pilot examination.

OBJECTIVES: To objectively evaluate and describe physical activity levels in children with a stable congenital heart defect and compare those levels with children who do not have a congenital heart defect. METHODS: We matched 21 pairs of children for gender and grade in school and gave them an accelerometer-based motion sensor to wear for 7 consecutive days. RESULTS: Physical activity levels did not differ between children with and without a congenital heart defect. During the 7 days of monitoring, children in this study spent most of their time in sedentary behaviours, that is, 6.7 hours of the 13 monitored hours, 54 minutes in moderate-intensity physical activity, and 12 minutes in vigorous-intensity physical activity. Less than one-fifth of all participants, with or without a congenital heart defect, accumulated sufficient physical activity to meet current physical activity recommendations for children and adolescents. CONCLUSION: Children with a stable congenital heart defect have activity behaviours that are similar to children without a congenital heart defect. Habitual physical activity in children with a congenital heart defect should be encouraged early on in life to develop strong physical activity habits that will hopefully follow them across their lifespan.

Near infrared spectroscopy: guided tilt table testing for syncope.

Syncope is transient loss of consciousness. Neurocardiogenic syncope (NCS) is the most common cause of syncope. Head-up tilt-table test (HUTT) has been used to demonstrate physiologic events during graded orthostatic challenge in individuals with significant handicap from NCS. Near-infrared spectroscopy (NIRS) provides a noninvasive, continuous method to monitor trends of regional tissue oxygenation (rSO2). We hypothesize that multisite NIRS monitoring will show differential desaturation patterns in the brain and renal vascular beds during postural stresses. All patients age 7-21 years old scheduled to undergo HUTT were recruited. Two probes for NIRS monitoring were placed on the forehead and above the left paravertebral level at the T10 to L1 space. These leads were attached to the Somanetics monitor (Somanetics, Troy MI). Tissue saturations (rSO2) obtained at two sites were recorded at rest, during the test, and throughout a 5-min recovery period. All data routinely obtained in HUTT were included in the research study database. Thirteen patients were recruited. The average age was 12.9 years. Five patients had a positive tilt-table test. The patients with syncope had rSO2 trends distinctly different from the normal subjects. In these patients, cerebral rSO2 showed a sudden decreasing trend from hypoperfusion, soon followed by various clinical symptoms. The cerebral rSO2 trend, which showed a dramatic increase, was paralleled by renal rSO2. These rSO2 trends were progressive until the patient was brought back to the supine position, which resulted in the rSO2 in both beds returning to baseline. Multisite NIRS-guided HUTT shows differential trends in the different vascular beds during postural gravitational stresses, and these patterns underlie the systemic oxygen consumption to flow-coupling dynamics observed during syncope.

Cerebral hemodynamics in the presence of decreased systemic venous compliance in patients with Fontan physiology may limit anaerobic exercise capacity.

Patients who have had the Fontan procedure report poor exercise performance. Fontan subjects can tolerate a higher level of sub maximal activity than might be anticipated from VO2, suggesting a different mechanism of exercise limitation. Near-infrared spectroscopy (NIRS) provides a non-invasive, continuous method to monitor regional tissue oxygenation (rSO2) and thereby a window into regional oxygen supply-demand relationships. We hypothesized that Fontan patients would have altered rSO2 trends from normal population that might reflect the mechanisms of exercise limitation. All the patients without structural or acquired heart disease and Fontan patients were eligible for inclusion if they were ordered to undergo cardiopulmonary exercise testing (CPET). Four-site regional rSO2 were recorded continuously during exercise. The difference between the oxyhemoglobin saturation measured by pulse oximetry (SpO2) and NIRS (rSO2) was computed as the regional arterial-venous saturation difference (AVDO2). A total of 33 normal subjects and five Fontan subjects scheduled for CPET were recruited. None of the Fontan subjects had a fenestration of the conduit. In the cerebral circulation, the Fontan patients have a significantly higher initial slope of increasing AVDO2 compared with normals. After vAT, the AVDO2 slope is flat for Fontan patients (p = 0.02). There is also a substantially larger rebound of cerebral rSO2 than in normal subjects after QT (p < 0.0001). Reduced anaerobic exercise capacity in Fontan patients may be secondary to limitation of cerebral blood flow, secondary to low systemic venous compliance due to absence of a sub-pulmonary ventricle, and augmented hyperventilatory response during exercise.

Evaluation of Cooper 12-minute walk/run test as a marker of cardiorespiratory fitness in young urban children with persistent asthma.

OBJECTIVE: To evaluate Cooper 12-minute run/walk test (CT12) as a one-time estimate of cardiorespiratory fitness and marker of fitness change compared with treadmill fitness testing in young children with persistent asthma. DESIGN: A cohort of urban children with asthma participated in the asthma and exercise program and a subset completed pre- and postintervention fitness testing. SETTING: Treadmill fitness testing was conducted by an exercise physiologist in the fitness laboratory at an academic children's hospital. CT12 was conducted in a college recreation center gymnasium. PARTICIPANTS: Forty-five urban children with persistent asthma aged 7 to 14 years participated in exercise interventions. A subset of 19 children completed pre- and postintervention exercise testing. INTERVENTIONS: Participants completed a 9-week exercise program where they participated in either swimming or golf 3 days a week for 1 hour. A subset of participants completed fitness testing by 2 methods before and after program completion. MAIN OUTCOME MEASURES: CT12 results (meters), maximal oxygen consumption ((.)Vo2max) (mL x kg(-1) x min(-1)), and treadmill exercise time (minutes). RESULTS: CT12 and maximal oxygen consumption were moderately correlated (preintervention: 0.55, P = 0.003; postintervention: 0.48, P = 0.04) as one-time measures of fitness. Correlations of the tests as markers of change over time were poor and nonsignificant. CONCLUSION: In children with asthma, CT12 is a reasonable one-time estimate of fitness but a poor marker of fitness change over time.

Measurement of regional tissue bed venous weighted oximetric trends during exercise by near infrared spectroscopy.

BACKGROUND: Cardiopulmonary exercise testing (CPET) is limited to children able to tolerate the equipment. Modification of instrumentation to reduce invasiveness will open CPET to a wider population. Near Infrared Spectroscopy (NIRS) devices measure regional oxyhemoglobin saturation (rSO2). We aim to predict anaerobic threshold (AT) during CPET using multiorgan NIRS monitoring. METHODS AND RESULTS: Nineteen subjects were recruited. NIRS probes were placed on the forehead, para vertebral space, vastus lateralis, and deltoid muscle (rSO2 C, rSO2 R, rSO2 L and rSO2 A). rSO2 was recorded at six second intervals at rest, exercise, and through a five minute recovery period. The AT was computed using the v-slope method. AT was also predicted using NIRS data by identifying the inflection point of the rSO2 trends for all the four sites. AT can be estimated by the point of slope change of rSO2 R, rSO2 C and the four-site composite measure. CONCLUSIONS: Multisite NIRS monitoring of visceral organs is a potential predictor of AT. This allows for monitoring in all forms of exercise over a wide age range.

Moderate and vigorous exercise programs in children with asthma: safety, parental satisfaction, and asthma outcomes.

BACKGROUND: Previous research suggests that physical activity programs may improve fitness and reduce symptoms in children with asthma, but few studies have included severe asthmatics and focused on safety and parental satisfaction with the programs. OBJECTIVE: To examine safety, parental satisfaction, and pre- to post-intervention changes in symptoms and quality of life (QOL) in a pilot study of the impact of vigorous physical activity (swimming) and moderate-intensity activity (golf) on inner-city children with asthma. DESIGN/METHODS: Children with asthma (7-14 years old) residing in Milwaukee's highest asthma prevalence zip codes were randomized to a 9-week swimming or golf program. Pre- and post-intervention data were obtained on safety, parental satisfaction, asthma symptoms, quality of life, and urgent asthma physician visits. RESULTS: Twenty-eight children in the swimming group and 17 in the golf group completed the program. Combined group analysis (N = 45) revealed that only six symptom exacerbations occurred during 1,125 person-sessions of swimming and golf (all resolved with bronchodilator therapy), 92% of parents were very or extremely satisfied with the program, and post-exercise decreases were observed in asthma symptom severity scores (9.3-7.3, P < 0.001), improved parental QOL (4.9-5.4, P < 0.001), and reduced urgent physician visits for asthma (1.3-0.2 visits per person, P = 0.04). The study lacked sufficient power to perform intergroup comparisons. CONCLUSIONS: Findings from this pilot study indicate that vigorous (swimming) and moderate-intensity (golf) physical activity programs are well-tolerated, safe, and achieve high parental satisfaction. Participants and parents reported reduced childhood asthma symptoms and physician office visits and improved parental QOL. These findings suggest a potentially beneficial role for moderate to vigorous physical activity in childhood asthma.

Chest pain: characteristics of children/adolescents.

Chest pain (CP) in children/adolescents is a common referral for the pediatric cardiologist. A group of 263 patients (141 males/122 females, mean age = 13.4 years, range = 5-22 years) with the primary complaint of CP underwent evaluation in the cardiac stress lab at Children's Hospital of Wisconsin. Echocardiograms at rest were obtained in 70% of patients with no significant cardiac abnormalities identified. Endurance time (EXT) and oxygen consumption (VO(2)/kg) were below predicted in 26% and 46%, respectively. Reactive airway disease (RAD) as a preexisting condition was reported in 19% of patients, but abnormal resting pulmonary function (PFTs) were found in 26% (n = 68), with 48/68 never having the diagnosis of RAD. At risk of overweight (BMI >85th percentile), was seen in 28% of the cohort, with 16% identified as being overweight (BMI >95th percentile). A significant difference in RAD (p < 0.01) was seen in African Americans (AA) and decreased EXT (p = 0.01) was seen in Hispanics (H). VO(2)/kg was significantly reduced in both AA and H (p < 0.01). These results identify both racial and age-related differences in the etiology of CP in children. Most importantly, true cardiac pathology is extremely rare. AOW, deconditioning, and respiratory compromise play important roles in CP. The need for comprehensive cardiopulmonary monitoring is emphasized by these findings.