Comparison of cardiovascular adjustments to exercise in adolescents 8 to 15 years of age after correction of tetralogy of fallot, ventricular septal defect or atrial septal defect

Cardiopulmonary functional capacity in Taiwanese children with ventricular septal defects

BACKGROUND

Children with ventricular septal defects (VSDs) are considered to have no difference in cardiopulmonary functional capacity with healthy children of the same age; however, studies have shown contradictory findings. The aim of this study was to assess whether Taiwanese children with VSDs exhibited cardiopulmonary deficits.

METHODS

This is a retrospective cohort study with the data collected from January 2010 to December 2021. All patients and controls (age-, sex-, and body mass index -matched) underwent cardiopulmonary exercise testing (CPET) and pulmonary function test.

RESULTS

In total, 157 VSD patients (80 patients with surgically closed VSDs, 77 patients with unrepaired VSDs) and 157 healthy controls were recruited. Pulmonary function test showed significant among-group differences in maximal voluntary ventilation (MVV) (p = 0.015). The surgically closed group had lower MVV compared to the control group. Regarding CPET, we found VSD patients had lower peak oxygen uptake than the controls (surgically closed group: 30.84 ± 6.27 ml/kg/min; unrepaired group: 32.00 ± 5.95 ml/kg/min; control group: 36.76 ± 6.50 ml/kg/min, p < 0.001). There was also significant among-group differences in aerobic capacity (surgically closed group: 21.20 ± 4.39 ml/kg/min; unrepaired group: 21.68 ± 4.47 ml/kg/min; control group: 26.25 ± 4.33 ml/kg/min, p < 0.001). In addition, the surgically closed group had lower heart rate average at anaerobic threshold than the control group (surgically closed group: 138.11 ± 16.42 bpm; control group: 145.78 ± 15.53 bpm, p = 0.002).

CONCLUSION

Taiwanese children with VSD, whether surgically closed or not, have poorer cardiopulmonary performance than age-matched healthy children, and the results of the surgically closed group were even worse.

Procedural and short-term outcomes of transcatheter closure of ventricular septal defect using lifetech multifunctional occluder: initial experience

The Lifetech Multifunctional occluder is a versatile device with an improved delivery and flexibility that reduces the risk of atrioventricular block. This is a retrospective, descriptive, pilot study done in 25 patients who underwent transcatheter closure of ventricular septal defect using Lifetech Multifunctional occluder from February 2017 to January 2018.The average age was 9.32 ± 7.20 years, with a range from 1 to 32 years. Procedural success was 100% with no case needing a change of device size. Closure rate on follow up was at 42% (10/24), 52% (12/23), and 81% (17/21) at 1 day, 1 month, and 6 months, respectively. At 6-month follow up, pre-procedure tricuspid regurgitation disappeared by 38%. However, the incidence of new onset tricuspid regurgitation to trace was 16% (2) and mild 8% (1). Pre-procedure mild aortic regurgitation remained the same status throughout the 6-month follow up. Closure of the defect did not improve or worsen the aortic regurgitation. Post-transcatheter closure of ventricular septal defect with mild infundibular hypertrophy, the 1-year-old patient had resolution of the infundibular hypertrophy after 6 months but our 9-year-old patient had persistence of the mild infundibular hypertrophy even after 6 months. One patient (4%) developed transient widened QRS complexes post-transcatheter closure that resolved after 1 month. In total, 92% of the patients had no periprocedural complications. While one patient each had an inadvertent urinary bladder puncture and device embolisation.Our retrospective review of the procedural and short-term outcomes of transcatheter closure of ventricular septal defect sizes 2-10 mm, using the Lifetech Multifunctional occluder, appears to be safe and effective. However, long-term follow up is warranted.

Atrial septal defect and exercise capacity: value of cardio-pulmonary exercise test in assessment and follow-up

Nearly four decades ago, the World Health Organization stated that functional capacity explorations best reflected the impact of a chronic disease on quality of life. Today, cardio-pulmonary exercise test (CPET) is recommended in the follow-up of patients with congenital heart diseases (CHDs). Indeed, the maximum oxygen uptake (VO_2max) and the ventilatory efficiency (VE/VCO₂ slope) correlate with both the prognosis and the quality of life in this population. Atrial septal defects (ASDs) represent the second most frequent CHD and are usually considered as simple CHDs. However, the exercise capacity of ASD patients may be impaired. Therefore, the CPET provides important information in assessment and follow-up of patients with ASDs, for both children and adults. Exercise capacity of patients with unrepaired ASDs depends on the importance of the shunt, the right ventricular (RV) function and volume overload, the level of pulmonary arterial pressure, and the occurrence of arrhythmias. For repaired ASDs, exercise capacity also depends on the delay before closure and the type of procedure (catheter or surgery). In most cases, the exercise capacity is nearly normal and CPET contributes to promote sports participation. In addition, a regular CPET follow-up is necessary to evaluate the occurrence, severity and physiological mechanisms of comorbidities, i.e., heart failure, pulmonary hypertension and arrhythmia. Furthermore, CPET follow-up in patients with ASDs may detect early onset of muscular deconditioning, for which cardiac rehabilitation may be considered.

Heart rate variability is impaired in adults after closure of ventricular septal defect in childhood: A novel finding associated with right bundle branch block

BACKGROUND

Ventricular septal defects (VSDs) generally have benign long-term prognoses, but recent studies have indicated increased pulmonary vascular resistance. A potential tool for monitoring pulmonary artery pressure is heart rate variability, and therefore, the aim of this study was to assess heart rate variability in adults with a surgically repaired or unrepaired VSD.

METHODS

In a long-term, follow-up study, three groups were included; VSD-patients operated in early childhood, patients with an open VSD, and controls. For each patient, 24-hour Holter monitoring was performed and heart rate variability was assessed.

RESULTS

In total, 30 participants with a surgically closed VSD, 30 participants with an unrepaired VSD, and 36 controls were included. In the closed VSD group, there was a higher proportion of participants, who had low sNN50 (p = 0.005) and low sNN6% (p = 0.017) than in the other two groups. Similar differences were found when sNN50 was divided into increases and decreases (p = 0.007 and p = 0.005, respectively) as well as sNN6% (p = 0.014 and p = 0.014, respectively). Lastly, there was a higher proportion of patients in the closed VSD group with low rMSSD than in the other two groups (p = 0.005). For the closed VSD group, the proportion of participants with low total sNN50 (p = 0.046) and low total sNN6% (p = 0.046) were higher among participants with a complete right bundle branch block (RBBB) than among participants with no or an incomplete RBBB.

CONCLUSIONS

Adults who had surgical VSD closure in early childhood had impaired heart rate variability and, particularly, participants with complete RBBB had lower heart rate variability.

Impaired cardiac output during exercise in adults operated for ventricular septal defect in childhood: a hitherto unrecognised pathophysiological response

BACKGROUND

Recent studies have demonstrated that surgical ventricular septal defect closure in childhood is associated with reduced functional capacity and disruption of the right ventricular force-frequency relationship during exercise. To further describe long-term cardiac function, we performed a non-invasive assessment of cardiac index during exercise in adults having undergone surgery for ventricular septal defect in early childhood.

METHODS

A total of 20 patients (surgical age 2.1±1.4 years, age at examination 22.1±2.2 years) and 20 healthy, matched controls (23.4±2.1 years at examination) underwent continuous supine bicycle ergometry during MRI. Their blood flow was recorded in the ascending aorta and the pulmonary trunk at increasing exercise levels. Cardiac index, retrograde flow, and vessel diameters were determined by blinded, post hoc analyses.

RESULTS

The patient group had normal cardiac index at rest (2.9±0.7 L/minute/m2), which was comparable with that of the controls (3.0±0.6 L/minute/m2); however, they had a lower increase in cardiac index during exercise (reaching 7.3±1.3 L/minute/m2 at submaximal exercise) compared with controls (8.2±1.2 L/minute/m2), p<0.05. Patients had a significantly higher ascending aorta retrograde flow than controls at rest and throughout exercise. In the pulmonary artery, the retrograde flow was minimal at rest in both groups, but increased significantly in patients during exercise compared with controls.

CONCLUSIONS

Young adults with a surgically closed ventricular septal defect have a reduced cardiac index during exercise compared with healthy, young adults. The impaired cardiac index appears to be related to an increasing retrograde flow in the pulmonary artery with progressive exertion.

Physical performance and physical activity in grown-up congenital heart disease

Aim

To review exercise performance and exercise habits in patients with congenital heart disease (CHD).

Background and methods

Physical exercise and physical activity has shown beneficial effects on the physical, psychological and social level in adult patients with cardiovascular disease. Favourable effects have also been documented in children with CHD. Exercise testing is preferentially performed on a treadmill in children, with the measurement of gas exchange.

Results

An overview of the literature showed that formal exercise testing has frequently documented reduced or suboptimal values for aerobic exercise performance in children with left-to-right shunts (atrial septal defect, ventricular septal defect), valvular heart disease and obstructive anomalies (aortic stenosis, pulmonary stenosis, coarctation of the aorta). Subnormal values for exercise tolerance have also been observed in patients with successfully repaired cyanotic heart disease (tetraology of Fallot, transposition of the great arteries, Fontan operation). An important contributing factor to the impaired exercise performance is the hypoactive lifestyle, as often observed in patients with CHD. This frequently results from parental or environmental overprotection.

Conclusion

These patients should be stimulated to be physically active, unless medical restriction is imposed. Fortunately, this represents only a small fraction of the total number of congenital heart defects for which sports participation is allowed.

Reduced long-term exercise capacity in young adults operated for ventricular septal defect

BACKGROUND

Ventricular septal defects are normally closed in early childhood, and post-surgically the patients are considered as healthy and fit as their peers. However, data are inconsistent. We exercise-tested a cohort of ventricular septal defect-operated patients and a group of matched controls to evaluate long-term physical fitness.

METHODS

Cardiopulmonary exercise capacity was tested on an ergometer cycle in 30 patients and 30 healthy age and gender-matched controls. Pulmonary ventilation and gas exchange were simultaneously measured breath-by-breath with Jaeger MasterScreen CPX® (CareFusion, San Diego, United States of America). During the test session, respiratory gas exchange was measured along with heart rate, blood pressure, and electrocardiogram. The endpoints were peak oxygen uptake, maximal workload, and ventilatory anaerobic threshold. The International Physical Activity Questionnaire and the SF-36 were applied for Health-Related Quality-of-Life assessment.

RESULTS

Ventricular septal defect-operated adults had a markedly lower peak oxygen uptake: mean 38.0(±8.2 ml O2/kg/minute) versus 47.9(±6.5 ml O2/kg/minute) in controls, p<0.01. Furthermore, ventilatory anaerobic threshold was impaired in ventricular septal defect patients: mean 25.3(±7.8 ml O2/kg/minute) versus 35.2(±7.7 ml O2/kg/minute) in controls, p<0.01. Maximal workload was reduced: mean 3.3(±0.7 W/kg) versus 4.0(±0.5 W/kg) in the control group, p<0.01. Lastly, ventricular septal defect patients had a significantly lower peak heart rate: mean 182(±8.8 beats/minute) versus 188(±9.0 beats/minute) in controls, p=0.03. Regarding Health-Related Quality of Life, the ventricular septal defect group had significantly lower scores in physical functioning, role physical, and social functioning.

CONCLUSION

Young adults with a surgically closed ventricular septal defect had a markedly reduced cardiopulmonary exercise capacity and a lower peak heart rate compared with controls.

Pulmonary cusp augmentation in repair of tetralogy of Fallot

BACKGROUND

pulmonary insufficiency after transannular patch repair of tetralogy of Fallot is associated with a poorer outcome.

OBJECTIVE

to compare the results of 2 techniques of transannular patch repair.

METHODS

93 patients with tetralogy of Fallot and hypoplasia of the right ventricular outflow tract underwent repair between 1990 and 2004 by 2 different techniques. Their ages ranged from 6 months to 12 years. The conventional transannular patch repair was used in 38 patients and 55 had transannular patch repair with pulmonary cusp augmentation.

RESULTS

mortality rates were 13.16% after conventional transannular patch repair and 0% after transannular patch repair with pulmonary cusp augmentation. Follow-up periods were 13-18 years (mean, 15.7±1.64 years) and 5-14 years (mean, 10.8±2.07 years), respectively. The early and midterm results demonstrated significantly more pulmonary insufficiency in the conventional repair group. Transannular patch repair with pulmonary cusp augmentation had longer bypass and operative times, but it was associated with a lower operative mortality than conventional repair. The long-term results showed differences in pulmonary insufficiency, cardiothoracic ratio, and rate of reoperation for pulmonary valve replacement.

CONCLUSION

reconstruction of the native pulmonary valve accompanied by pulmonary cusp augmentation can reduce postoperative pulmonary insufficiency and has a more favorable long-term outcome.

Exercise performance and activity level in children with transposition of the great arteries treated by the arterial switch operation

The exercise capacity of children after arterial switch for transposition of the great arteries (TGA) is known to be at the lower limit of normal. We aimed to ascertain whether this results from compromised hemodynamics or deconditioning. A total of 17 children with TGA (12 male and 5 female children; age 12.1 + or - 2.0 years) treated with the arterial switch operation were compared with 20 age-matched controls (13 male and 7 female children; age 12.8 + or - 2.4 years) regarding their peak exercise capacity, peak workload, and peak heart rate, as assessed by cycle ergometry. The children's physical activity level was monitored for a 7-day period using a pedometer and diary, and a questionnaire was used to assess physical activity participation and overprotection. The results demonstrated that TGA children showed a significantly reduced peak exercise capacity (47.4 + or - 6.4 vs 41.1 + or - 6.6 ml/kg/min; p <0.05), maximal workload (3.7 + or - 0.5 vs 3.1 + or - 0.6 W/kg; p <0.01), and maximal heart rate (189 + or - 9 vs 180 + or - 14 beats/min; p <0.05) compared to the controls. No significant differences were found in the physical activity pattern or overprotection. In conclusion, given the comparable physical activity level, but reduced exercise capacity in the TGA children, these children most likely fall short in their exercise performance because of restrictive hemodynamics rather than deconditioning from reduced daily life activity.

Exercise performance after surgery for pulmonary atresia and intact ventricular septum

The objective of this study was to assess exercise performance in subjects born in Sweden between 1980 and 1995 and undergoing surgery for pulmonary atresia and intact ventricular septum and to identify determinants of exercise performance. Twenty-seven subjects, 16 with biventricular repair and 11 with univentricular palliation, and 28 age- and sex-matched controls completed cardiopulmonary exercise and lung function testing. Peak oxygen uptake was determined using a symptom-limited ramp bicycle exercise protocol. Regression analysis was performed to identify predictors of peak oxygen uptake (V'O(2)), The index group had lower peak V'O(2) (1.4 [median 0.8; range 2.5] l/min) than controls (1.9 [0.7; 3.1]; p < 0.05). Subjects without ventriculocoronary arterial communications (VCAC), corrected to biventricular circulation, had higher peak V'O(2), than the remaining index subjects. Decreased total lung capacity, low minute ventilation, and high physiologic dead space measured at peak exercise were all independent determinants of low peak V'O(2) Exercise capacity is generally decreased in subjects with pulmonary atresia and intact ventricular septum, although there are marked interindividual differences. Good exercise capacity was found in subjects without VCAC who had undergone biventricular repair. Decreased lung function was an unfavourable predictor of exercise capacity.

Exercise capacity and participation of children with a ventricular septal defect

Existing data on exercise performance in children with a ventricular septal defect (VSD) are scarce and inconclusive. We aimed to elucidate whether and why exercise capacity and physical activity level are decreased in children with VSD. Children 9 to 17 years of age with a surgically (operated, n = 13) or conservatively (unoperated, n = 14) managed VSD were compared with healthy peers (controls, n = 15) regarding (1) anthropometric and spirometric measurements; (2) cycle ergometric performance in terms of peak oxygen uptake, peak heart rate, and peak workload; and (3) mean daily energy expenditure. All subjects completed a questionnaire on physical activity participation, overprotection, and self-perceived fitness and health. Anthropometric variables were comparable among groups, whereas lung function at rest was mildly decreased in the 2 VSD subgroups. Exercise testing succeeded in all 42 subjects; valid results were obtained in 39. Weight- and body fat-adjusted peak oxygen uptake, peak workload, and energy expenditure were not significantly different among groups. Peak heart rate emerged as significantly lower in operated subjects, which was not attributable to poorer effort. Physical fitness and general health were rated comparably among groups, whereas participation in sports was markedly lower in children with VSD. Discouragement from engaging in (strenuous) exercise occurred equally infrequently in children with VSD and controls. In conclusion, children with patent or surgically closed VSDs have a normal exercise capacity, despite a mild chronotropic limitation in the latter. Previous cardiac surgery did not influence these children's exercise performance. These children consider themselves healthy, they exhibit a normal habitual physical activity level, and they are not withheld from (strenuous) exercise.

Coronary artery pattern and age impact exercise performance late after the arterial switch operation

OBJECTIVE

The impact of coronary artery pattern on exercise performance after the arterial switch operation is unknown. The purpose of this study was to evaluate the relationship between coronary artery pattern and exercise performance late after the arterial switch operation.

METHODS

Patients who underwent the arterial switch operation and were referred for exercise stress testing between January of 1996 and April of 2005 were included. Univariate and multivariate analyses were performed to identify risk factors for lower maximum heart rate and percent of predicted peak oxygen consumption.

RESULTS

Fifty-three patients were included; 72% were male. The median age at the arterial switch operation was 5 days (1 day to 3.6 years); 32% had concurrent ventricular septal defect repair. The time from the arterial switch operation to exercise stress testing was 14.1 years (7.7-20.6 years). There were 37 patients with the usual coronary artery pattern, and 16 patients (30%) with variant coronary artery patterns. At exercise stress testing, there was no difference in respiratory exchange ratio (1.16 +/- 0.1 for both), indicating similar effort. Compared with patients with the usual coronary artery pattern, patients with variant coronary artery patterns had a significantly lower maximum heart rate (177 +/- 16 beats/min [89% predicted] vs 186 +/- 11 beats/min [93% predicted], respectively, P = .04). Percent of predicted peak oxygen consumption was not significantly different between patients with the usual coronary pattern and patients with variant coronary artery patterns (89% +/- 20% vs 80% +/- 17%, respectively, P = .12). In multivariate analysis, variant coronary artery patterns (P = .03) and ventricular septal defect (P = .004) were predictors of significantly lower maximum heart rate and were associated with a trend toward lower percent of predicted peak oxygen consumption (P < .09). Longer follow-up time was the strongest predictor of lower percent of predicted peak oxygen consumption (P < .001).

CONCLUSIONS

Variant coronary artery patterns are associated with chronotropic impairment, and longer follow-up time is the strongest predictor of diminished aerobic capacity late after arterial switch operation.

Indications for Heart Transplantation in Pediatric Heart Disease

Background— Since the initial utilization of heart transplantation as therapy for end-stage pediatric heart disease, improvements have occurred in outcomes with heart transplantation and surgical therapies for congenital heart disease along with the application of medical therapies to pediatric heart failure that have improved outcomes in adults. These events justify a reevaluation of the indications for heart transplantation in congenital heart disease and other causes of pediatric heart failure.

Methods and Results— A working group was commissioned to review accumulated experience with pediatric heart transplantation and its use in patients with unrepaired and/or previously repaired or palliated congenital heart disease (children and adults), in patients with pediatric cardiomyopathies, and in pediatric patients with prior heart transplantation. Evidence-based guidelines for the indications for heart transplantation or retransplantation for these conditions were developed.

Conclusions— This evaluation has led to the development and refinement of indications for heart transplantation for patients with congenital heart disease and pediatric cardiomyopathies in addition to indications for pediatric heart retransplantation.

Physical Activity Patterns of Children After Neonatal Arterial Switch Operation

BACKGROUND

Physical inactivity is a major atherosclerosis risk factor. The exercise tolerance is usually excellent after neonatal arterial switch operation, but those patients in whom coronary anomalies remain the main late complication, risk developing atherosclerotic coronary disease owing to perceived physical activity restrictions.

METHODS

We investigated physical activity patterns of 52 unselected children 7 to 14 years after neonatal arterial switch operation for transposition of the great arteries by 24-hour continuous heart rate monitoring. The percentage of heart rate reserve was used to measure the amounts of activities. Comparisons were made with 35 children with repaired atrial or ventricular septal defect and with 127 age-matched healthy children.

RESULTS

Children after arterial switch operation accumulated 167.3 +/- 70.6, 25.3 +/- 12.9, and 15.7 +/- 11.3 minutes a day (mean +/- SD) of light, moderate, and vigorous physical activities, respectively. At the same activity levels, children with repaired septal defect accumulated 165.2 +/- 82.2, 26.2 +/- 11.7, and 16.2 +/- 9.1 minutes a day, and their healthy peers 164.8 +/- 74.5, 31.8 +/- 13.9, and 21.9 +/- 11.3 minutes a day. Both cardiac groups were significantly less active than the control group when considering moderate (p = 0.026) and vigorous activities (p = 0.006). Only 19% and 27% of the children after arterial switch operation engaged, respectively, in more than 30 minutes a day of moderate activity and 20 minutes a day of vigorous activity.

CONCLUSIONS

Children after arterial switch operation, just like other cardiac children, do not meet the guidelines for physical activity. We should encourage regular physical activity to offset adult sedentary behavior and to prevent atherosclerotic cardiovascular disease in those patients whose long-term function of the coronary arteries remains a matter of concern.

Long-term assessment and serial evaluation of cardiorespiratory exercise performance and cardiac function in patients with atrial switch operation for complete transposition

BACKGROUND

At present, a considerable number of patients survive who underwent an atrial switch operation for correction of complete transposition. Our study aimed to assess their long-term exercise performance and the serial evolution of cardiac function.

METHODS

We studied 22 patients 5 to 17 years after an atrial switch operation, and followed them serially for 3.5 +/- 2 years after the first evaluation. Cardiorespiratory exercise function was assessed by analysis of gas exhange and by determination of the ventilatory anaerobic threshold. Echocardiography was performed on all evaluations.

RESULTS

All patients were in Class I of the classification of the New York Heart Association at all assessments. Ventilatory anaerobic threshold, however, was significantly lower than normal. It averaged 77.9% +/- 13.7 of the normal mean value at the initial evaluation, and remained stable when re-evaluated later (76.2 +/- 13.7%). At the initial study, the increase in oxygen uptake during graded exercise was below the 95% confidence limit in 6 of the patients, and was below this level in 10 patients at re-assessment. The subnormal values for oxygen uptake during submaximal exercise were associated with moderate to severe haemodynamic dysfunction. At echocardiography, 15 of 17 patients studied twice had mild to moderate right ventricular dilation and tricuspidregurgiation, which remained virtually the same at reasssesment. A stable sinus rhythm was initially present in 17 patients, and persisted in 15 patients during follow-up.

CONCLUSION

At medium term follow-up, cardiorespiratory exercise performance remains stable in patients after atrial switch repair. Serial exercise testing appears useful, because in individual patients in the present study, a decreasing exercise tolerance correlated with development of haemodynamic sequels.

Oxygen uptake versus exercise intensity: a new concept in assessing cardiovascular exercise function in patients with congenital heart disease

OBJECTIVE

To assess the relation between exercise intensity and oxygen uptake during graded exercise in paediatric patients who underwent surgical repair of congenital heart disease, and to compare it with conventional measures of aerobic exercise function.

DESIGN

Cross sectional study. Exercise testing was performed on a treadmill and gas exchange was measured on a breath by breath basis.

PATIENTS

29 patients who underwent an atrial switch operation for transposition of the great arteries (TGA) (mean (SD) age at testing 10.3 (2.5) years) and 30 patients who underwent total repair of tetralogy of Fallot (TF) (age 12.1 (3.3) years) performed graded exercise testing. Exercise responses were compared with data obtained in 24 normal controls (age 11.4 (2.6) years).

RESULTS

The slope of oxygen uptake versus exercise intensity averaged 1.50 (0. 64) ml O(2)/min(2)/kg in the patients with TGA and 1.68 (0.75) ml O(2)/min(2)/kg after TF repair, both lower (p < 0.005) than in normal controls (2.42 (0.68) ml O(2)/min(2)/kg). The lower slope of oxygen uptake was correlated with a subnormal value for ventilatory anaerobic threshold, which averaged 78.0 (13.3)% of normal in TGA and 85.1 (10.6)% in TF. This was associated with a steeper slope (p = 0.001) of carbon dioxide output versus oxygen uptake above the ventilatory anaerobic threshold in TGA (1.26 (0.20)) and TF (1.20 (0. 18)) compared with the normal controls (1.05 (0.13)), and also a steeper slope of ventilation versus carbon dioxide in TGA (47.0 (15. 4)) and TF (41.5 (13.7)) than in the controls (30.3 (8.5)).

CONCLUSIONS

Calculation of the steepness of the slope of oxygen uptake versus exercise intensity is a valid measurement of oxygen flow to the exercising tissues, which may be limited in congenital heart disease.

Evaluation of right ventricular systolic pressure during incremental exercise by Doppler echocardiography in adults with atrial septal defect

STUDY OBJECTIVES

Pulmonary hypertension is the most important complication in patients with atrial septal defect (ASD), but its role in limiting exercise has not been examined. This study sought to evaluate exercise performance in adults with ASD and determine the contribution of elevated pulmonary artery pressure in limiting exercise capacity.

DESIGN

We used Doppler echocardiography during exercise in 10 adults (aged 34 to 70 years) with isolated ASD (New York Heart Association class I, II) and an equal number of matched control subjects. Incremental exercise was performed on an electrically braked upright cycle ergometer. Expired gases and VE were measured breath-by-breath. Two-dimensional and Doppler echocardiographic images were obtained at rest prior to exercise to determine ASD size, stroke volume (SV), shunt ratio (Qp:Qs), right ventricular outflow tract (RVOT) size, and right ventricular systolic pressure at rest (RVSPr). Doppler echocardiography was repeated at peak exercise to measure right ventricular systolic pressure during exercise (RVSPex).

RESULTS

Resting echocardiography revealed that RVOT was larger (21+/-4 vs 35+/-8 mm, mean+/-SD; p=0.0009) and RVSPr tended to be higher (17+/-8 vs 31+/-8 mm Hg; p=0.08) in ASD; however, left ventricular SV was not different (64+/-23 vs 58+/-23 mL; p>0.05), compared with control subjects. Despite normal resting left ventricular function, ASD patients had a significant reduction in maximum oxygen uptake (VO2max) (22.9+/-5.4 vs 17.3+/-4.2 mL/kg/min; p=0.005). RVSPex was higher (19+/-8 vs 51+/-10 mm Hg; p=0.001) and the mean RVSP-VO2 slope (1+/-2 vs 18+/-3 mm Hg/L/min; p=0.003) and intercept (17+/-4 vs 27+/-4 mm Hg; p=0.05) were higher in the ASD group. VO2max correlated inversely with both RVSPr (r=-0.69; p=0.007) and RVSPex (r=-0.67; p=0.01).

CONCLUSION

These findings suggest that adults with ASD have reduced exercise performance, which may be associated with an abnormal increase in pulmonary artery pressure during exercise.

Role of right ventricular and pulmonary functional abnormalities in limiting exercise capacity in adults with congenital heart disease

This study evaluates right ventricular (RV) and pulmonary function during exercise in adults with congenital heart disease (CHD). Thirty-one patients with CHD involving the right side of the heart underwent symptom-limited bicycle exercise testing with simultaneous expired gas analysis and measurement of RV ejection fraction (EF). Twenty-one age-matched normal controls underwent the identical exercise protocol. Maximal oxygen consumption was lower in the CHD than in normal controls (19.5 +/- 6.4 vs 30.5 +/- 0.8 ml/kg/min, p = 0.0001 patients vs controls). Both heart rate (156 +/- 25 vs 171 +/- 13 beats/min, p = 0.01) and oxygen pulse (9.3 +/- 3.7 vs 12.3 +/- 3.7 ml/beat, p = 0.01), an indirect measure of stroke volume, were found to be lower in the CHD group at peak exercise. Pulmonary dysfunction was evidenced in the CHD group by decreased forced expiratory volume, forced vital capacity and maximum voluntary ventilation, and by a higher ventilation/expired carbon dioxide ratio at peak exercise (37.2 +/- 6.9 vs 33.0 +/- 5.4, p = 0.02), suggesting an increase in dead space ventilation. Maximal oxygen consumption was lower in patients whose RVEF decreased with exercise (17.6 +/- 5.4 vs 22.8 +/- 6.4 ml/kg/min, p = 0.03 "decrease RVEF" group vs "increase RVEF" group). Maximal oxygen consumption correlated with the change in RVEF only in the group whose RVEF decreased with exercise (r = 0.5, p = 0.03). In the group that had increased RVEF with exercise, maximal oxygen consumption correlated with forced expiratory volume (r = 0.7, p = 0.02). Thus, adults with CHD have a reduced functional capacity compared with normal controls. This phenomenon appears to be associated with both RV and pulmonary abnormalities.

Pre- and postoperative exercise capacity associated with hemodynamics in adult patients with atrial septal defect: a retrospective study

OBJECTIVE

This study evaluated the pre- and postoperative exercise capacity in adult patients with atrial septal defect (ASD) associated with hemodynamic variables.

METHODS

Adults (70) with ASD underwent symptom-limited exercise tests. Peak O2 uptake (Peak VO2) and % peak VO2, that is the percentage of predicted value, were measured. These patients were divided into three groups according to pulmonary-to-systemic flow ratio (Qp/Qs) and systolic pulmonary arterial pressure (PAs); Group A: Qp/Qs < or = 3, PAs < or = 50 mm Hg, Group B: Qp/Qs > 3, any PAs, Group C: Qp/Qs < or = 3, PAs > 50 mm Hg. Exercise test was repeated in 22 patients after surgical closure of ASD (mean 4.6 +/- 2.0 months).

RESULTS

Peak VO2 was significantly lower in group B (P < 0.01) and group C (P < 0.01) than in group A (19.3 +/- 5.7, 17.6 +/- 3.6, 27.6 +/- 6.3 ml/min/kg, respectively). In patients except those in group C, there were a weak negative correlation between PAs and % peak VO2 (r = 0.61) and a significant negative correlation between Qp/Qs and % peak VO2 (r = 0.86). Postoperative peak VO2 increased significantly in group A (27.2 +/- 5.1-31.1 +/- 5.1 ml/min/kg, P < 0.05) and group B (16.7 +/- 3.3-21.5 +/- 2.1 ml/min/kg, P < 0.01). However, there was no significant difference between pre- and postoperative peak VO2 in group C (16.8 +/- 1.3-17.8 +/- 2.8 ml/min/kg, NS).

CONCLUSIONS

In ASD patients except those with small or moderate left-to-right shunt and high pulmonary arterial pressure, there was a significant negative correlation between Qp/Qs and peak VO2 corrected by age and gender. Patients with large left-to-right shunt and/or high pulmonary arterial pressure had reduced exercise capacity. However, exercise capacity in patients with large left-to-right shunt increased after closure of ASD regardless of whether they had high pulmonary arterial pressure.

Cardiorespiratory response to exercise after venous switch operation for transposition of the great arteries

STUDY OBJECTIVES

This study reports on the cardiorespiratory response to graded exercise in patients after venous switch operation for transposition of the great arteries.

DESIGN

Several small studies have documented a diminished exercise tolerance after Mustard repair for transposition of the great arteries, little information exists, however, about long-term cardiorespiratory exercise performance in patients who have had the Senning procedure.

PATIENTS

This prospective study reports on the serial long-term (mean, 11 +/- 2.8 years) cardiopulmonary exercise performance of 43 patients (age, 12 +/- 3.1 years) who underwent a Senning procedure, with no significant postoperative abnormalities. Forty-three matched healthy children were also studied as a control group.

MEASUREMENTS AND RESULTS

All underwent exercise testing (Bruce protocol) with metabolic gas exchange to determine parameters at 3 min, anaerobic threshold, similar heart rate (150 beats/min), and peak exercise. Time of exercise was 10.5 +/- 1.9 min in patients and 13.4 +/- 2 min in control subjects (p = 0.0001). Overall, patients reached 73% of peak oxygen uptake achieved by control subjects (32.6 +/- 5.6 vs 44.7 +/- 6 mL/kg/min). Chronotropic response (188 +/- 15.7 vs 166.5 +/- 19.6 beats/min [p = 0.0001]) and oxygen pulse (7.4 +/- 2.9 vs 10.7 +/- 4.2 mL/beat [p = 0.0002]) were lower in patients at peak exercise. Patients had a greater respiratory response to exercise: both respiratory rate and ventilatory equivalent for carbon dioxide were significantly higher at all stages of exercise. Exercise capacity assessed by peak oxygen uptake was correlated with time elapsed since surgical repair (r = 0.48; p = 0.001).

CONCLUSIONS

It is concluded that even in asymptomatic patients, exercise endurance and respiratory response are generally altered as much as 11 +/- 2.8 years after venous switch operation, although early surgical repair is predictive of a better long-term functional result.

Role of exercise in the management of cardiovascular disease in children and youth

Most cardiovascular disease in children and youth is the result of congenital anomalies. Surgical techniques for repair of these defects have improved greatly since they were first developed, and a high percentage of patients become healthy, active adults. Less frequently, other types of cardiovascular disease may be acquired sometime after birth. In patients with either congenital or acquired heart disease, there is often some degree of exercise limitation. Appropriately, there is an increasing interest in the use of exercise testing and training in the clinical management of both congenital and acquired cardiovascular disease in children and youth. This review describes the exercise responses of patients with various forms of cardiovascular disease and discusses the use of exercise training to improve the well-being of these children and adolescents.

Lung function in VSD patients after corrective heart surgery

Static lung volumes, lung elasticity, and airway patency indices were measured in 47 children operated on for ventricular septal defect (VSD). Open-heart surgery was performed at the age of 0.6-12.0 years (median 4.1 years). In the first group (34 subjects), after primary repair of the VSD, there was an increase in lung recoil pressure at 100% of total lung capacity (TLC) (128% of the predicted value) and a reduction in specific airway conductance (sGaw) (75% of the predicted value). In the second group (13 patients), who had had previous pulmonary artery banding at 0.2-4.0 years (median 0.7 year) there was an increased functional residual capacity/TLC ratio (111% of predicted value), reduced sGaw (69% of predicted value), and reduced maximum expiratory flow at 25% of vital capacity (79% of predicted value). Lung volumes were insignificantly reduced in both groups. The frequency of lung function disturbances was similar in the two groups (71% of patients in the former group and 77% of patients in the latter group). A linear positive correlation between specific airway conductance and the mean pulmonary artery pressure (mPAP) (r = 0.793, p < 0.006) was observed in children with an mPAP <30 mmHg prior to open-heart surgery. A positive correlation between static recoil pressure at full inflation and mPAP (r = 0.545, p < 0.03) was found in children with an mPAP > 30 mmHg. The severity of congenital heart disease prior to surgery and the influence of the timing of the surgical procedures may cause the differences in lung function tests between the groups.

Serial cardiorespiratory exercise testing in patients with congenital heart disease

Aerobic capacity of patients with different forms of congenital heart disease was serially evaluated in 79 patients and the evolution was correlated with the lesion and the level of daily activity. The patients were divided into six groups: patients with a small ventricular septal defect (VSD) with mini shunt (n = 14), mild pulmonary valve stenosis with gradient < 40 mm Hg (PS) (n = 12), mild to moderate aortic valve stenosis (gradient 36 +/- 17 mmHg) (AS) (n = 12), patients 4.7 +/- 2.1 years after repair of tetralogy of Fallot (PO-TF) (n = 16), patients 2.2 +/- 2.9 years after closure of a high flow/high gradient VSD (PO-VSD) (n = 13), and patients 2.6 +/- 1.7 years after Fontan repair (Fontan-PO) (n = 12). Aerobic capacity was assessed by determination of the ventilatory anaerobic threshold (VAT). VAT reflects the highest aerobic exercise level prior to a disproportionate increase of CO2 and ventilation relative to O2 uptake; it is independent of patient motivation. Data are expressed as percentage of normal O2 uptake at VAT, determined in 234 age/gender matched controls. The habitual level of physical activity was assessed by a standardised questionnaire. Aerobic capacity in all subgroups of patients, even with very mild defects, was at or below the lower limit of normal. Children left unrestricted from physical exercise (VSD, PS, PO-VSD) had no change over the study period. However, aerobic capacity of patients with medically imposed physical restrictions (AS) and significant residual haemodynamic lesions (PO-TF, Fontan) decreased with age.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiopulmonary performance during exercise in patients with repaired tetralogy of Fallot with absent pulmonary valve

In patients with tetralogy of Fallot and absent pulmonary valve, the dilated pulmonary arteries sometimes result in bronchial compression and pulmonary symptoms due to airway obstruction, recurrent pulmonary infection, and development of bronchiectasis. After complete intracardiac repair, residual pulmonary disease may be expected to result in impaired cardiopulmonary performance during exercise. To assess this hypothesis, nine patients with tetralogy of Fallot and absent pulmonary valve underwent exercise testing and were compared to 38 patients with tetralogy of Fallot repaired using a transannular patch. All patients were exercised to maximum volition using a 1 minute incremental treadmill protocol with monitoring of pulmonary functions and expired gases. Maximal heart rate, maximal oxygen consumption, oxygen consumption at anaerobic threshold, and maximal respiratory exchange ratio were similar for the two groups. There was no significant difference for ventilation and gas exchange parameters at rest or at maximal exercise, and values for both groups were below the predicted normal for healthy subjects. Breathing reserve, however, did tend to be somewhat lower in the group with tetralogy of Fallot with absent pulmonary valve. In summary, despite significant preoperative symptoms, cardiopulmonary performance during exercise in patients with tetralogy of Fallot and absent pulmonary valve is similar to patients with tetralogy of Fallot repaired with a transannular patch.

Oxygen uptake transient kinetics during constant-load exercise in children after operations of ventricular septal defect, tetralogy of Fallot, transposition of the great arteries, or tricuspid valve atresia

Cardiovascular function accounts for endurance performance and, by a rapid increase in oxygen supply at the onset of exercise, contributes to short-lasting intensive exertion prevailing in many kinds of sports activities. This study determined the time for oxygen uptake (VO2) to reach one half of its asymptotic level above rest, and the respective oxygen deficit following the onset of a constant-load exercise corresponding to 80% to 90% of the maximal oxygen uptake (VO2max) in 35 children after surgical closure of a ventricular septal defect, after corrective surgery for tetralogy of Fallot, or after the Senning, Mustard, or Fontan procedures. In addition, VO2max and maximal blood lactate were determined. The half-time of VO2 response and oxygen deficit was lowest in patients after closure of a ventricular septal defect, whereas children had the most unfavorable VO2 transient kinetics after Fontan operation or with a transannular patch after correction of tetralogy of Fallot. A negative correlation was evaluated between half-time of VO2 response and VO2max, whereas maximal blood lactate varied independently of VO2max. It is concluded that many children with decreased VO2max after cardiac surgery also have unfavorable VO2 transient kinetics. In addition to being less qualified for endurance performance, they are also less prepared for short-lasting intensive energy expenditure. Therefore, the primary aim of training in these children is to improve the economy of motion of the respective tasks.

Time course of oxygen uptake and heart rate during Bruce treadmill test in patients following surgery for tetralogy of Fallot

Exercise performance was examined in 14 patients with a prior history of surgical repair for tetralogy of Fallot. Using a Bruce protocol, we evaluated the time course of oxygen uptake and heart rate in these patients and compared them with a standard curve obtained from 63 sex- and age-matched healthy children. Five of the 14 patients had unusual findings. The heart rate increased rapidly in four of them, while the oxygen uptake increased gradually (95% confidence lower limit). It is hypothesized that a reduction in stroke volume during exercise was responsible for these abnormal findings. The remaining unusual finding was in a patient who was known to have myocardial fibrosis and vacuolization. In this particular case, the time course of oxygen uptake and heart rate were both below the 95% coefficient of variation from the beginning to the end of exercise. In patients who have undergone surgical repair for tetralogy of Fallot, the analysis of oxygen uptake time course and the heart rate may provide valuable information for the long-term follow-up.

Cardiorespiratory exercise capacity after surgical closure of atrial septal defect is influenced by the age at surgery

To study the influence of age at the time of the operation on long-term functional performance in children undergoing surgery for atrial septal defect (ASD) of the secundum type, exercise tolerance was assessed in 24 patients and values were compared with those of normal subjects. Patients were divided into two groups: 11 patients had surgery before the age of 5 years (group 1) and 13 patients had surgery at a later age (group 2). There were no significant differences between groups 1 and 2 with regard to the pulmonary-to-systemic flow ratio, pulmonary artery pressure, and the interval between surgery and exercise testing. Performance capacity was assessed by determination of the ventilatory threshold during submaximal exercise. The mean value for the ventilatory threshold in group 1 was normal (99.4 +/- 15.1% of the age-predicted normal value). In the children who were more than 5 years of age at the time of the operation, the ventilatory threshold was below normal (84.5 +/- 10.9% of the age-predicted normal value). Furthermore, in group 2 more patients (77%) had values that were below normal (below the 95% confidence limit of the age-predicted normal value) compared with group 1 (27%). It is concluded that functional performance capacity is better when surgical closure of ASD is performed in early childhood and before the age of 5 years rather than at a later age.