Exercise testing after the Fontan operation

Health related quality of life among Rheumatic Fever and Rheumatic Heart Disease patients in India

Background

Measurement of health-related quality of life (HRQOL) of people with chronic illnesses has become extremely important as the mortality rates associated with such illnesses have decreased and survival rates have increased. Thereby, such measurements not only provide insights into physical, mental and social dimensions of patient’s health, but also allow monitoring of the results of interventions, complementing the traditional methods based on morbidity and mortality.

Objective

The present study was conducted to describe the HRQOL of patients suffering from Rheumatic Fever (RF) and Rheumatic Heart Disease (RHD), and to identify socio-demographic and clinical factors as predictors of HRQOL.

Methodology

A cross-sectional study was conducted to assess the HRQOL among 702 RF and RHD patients using EuroQol 5-dimensions 5-levels instrument (EQ-5D-5L), EuroQol Visual Analogue Scale and Time Trade off method. Mean EQ-5D-5L quality of life scores were calculated using EQ5D index value calculator across different stages of RF and RHD. Proportions of patients reporting problems in different attributes of EQ-5D-5L were calculated. The impact of socio-economic determinants on HRQOL was assessed.

Results

The mean EQ-5D-5L utility scores among RF, RHD and RHD with Congestive heart failure patients (CHF) were estimated as 0.952 [95% Confidence Interval (CI): 0.929–0.975], 0.820 [95% CI: 0.799–0.842] and 0.800 [95% CI: 0.772–0.829] respectively. The most frequently reported problem among RF/RHD patients was pain/discomfort (33.8%) followed by difficulty in performing usual activities (23.9%) patients, mobility (22.7%) and anxiety/depression (22%). Patients with an annual income of less than 50,000 Indian National Rupees (INR) reported the highest EQ-5D-5L score of 0.872, followed by those in the income group of more than INR 200,000 (0.835), INR 50,000–100,000 (0.832) and INR 100,000–200,000 (0.828). Better HRQOL was reported by RHD patients (including RHD with CHF) who underwent balloon valvotomy (0.806) as compared to valve replacement surgery (0.645).

Conclusion

RF and RHD significantly impact the HRQOL of patients. Interventions aiming to improve HRQOL of RF/RHD patients should focus upon ameliorating pain and implementation of secondary prevention strategies for reducing the progression from ARF to RHD and prevention of RHD-related complications.

Contributions of residual hypoxemia to exercise hyperventilation in Fontan patients

It is unsettled whether increased exercise ventilation in Fontan subjects is due to increased pulmonary dead space or augmented ventilatory drive. Twenty-six Fontan patients underwent symptom-limited treadmill cardiopulmonary exercise testing. Two groups of age- and sex- matched subjects served as controls: the biventricularly repaired (Bi, n = 18), and the "true" control (C, n = 29) groups. Peak oxygen uptake (V̇O_2peak) was not different among groups (41.0 +/- 8.4 ml/min/kg, 43.5 +/- 6.6 ml/min/kg, and 45.9 +/- 11.6 ml/min/kg for Fontan, Bi, and C groups, respectively, p = 0.16). Fontan subjects, however, showed steeper alveolar ventilation/carbon-dioxide (V̇A/V̇CO₂) regression slope (35.5 +/- 5.3, 28.7 +/- 3.8, and 29.5 +/- 3.0 l/ml, for Fontan, Bi, and C groups, respectively, p<0.0001), and lower end-expiratory carbon-dioxide fraction (FetCO_2VAT) at ventilatory threshold (VAT) (4.4 +/- 0.5%, 5.5 +/- 0.5%, and 5.5 +/- 0.4%, for Fontan, Bi, and C groups, respectively, p<0.001). The dead-space ventilation fraction at VAT was similar among groups (0.33 +/- 0.06, 0.33 +/- 0.04, 0.35 +/- 0.05 for Fontan, Bi, and C groups, respectively, p = 0.54). In Fontan subjects, arterial oxygen saturation at rest (SaO_2rest) was correlated with V̇A/V̇CO₂ regression slope (r = -0.41, p = 0.04) and with FetCO_2VAT (p = -0.53, p<0.01). We conclude that Fontan patients show exercise hyperventilation due to augmented central and/or peripheral ventilatory drive, which is further augmented by residual hypoxemia.

Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association

It has been 50 years since Francis Fontan pioneered the operation that today bears his name. Initially designed for patients with tricuspid atresia, this procedure is now offered for a vast array of congenital cardiac lesions when a circulation with 2 ventricles cannot be achieved. As a result of technical advances and improvements in patient selection and perioperative management, survival has steadily increased, and it is estimated that patients operated on today may hope for a 30-year survival of >80%. Up to 70 000 patients may be alive worldwide today with Fontan circulation, and this population is expected to double in the next 20 years. In the absence of a subpulmonary ventricle, Fontan circulation is characterized by chronically elevated systemic venous pressures and decreased cardiac output. The addition of this acquired abnormal circulation to innate abnormalities associated with single-ventricle congenital heart disease exposes these patients to a variety of complications. Circulatory failure, ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, protein-losing enteropathy, and plastic bronchitis are potential complications of the Fontan circulation. Abnormalities in body composition, bone structure, and growth have been detected. Liver fibrosis and renal dysfunction are common and may progress over time. Cognitive, neuropsychological, and behavioral deficits are highly prevalent. As a testimony to the success of the current strategy of care, the proportion of adults with Fontan circulation is increasing. Healthcare providers are ill-prepared to tackle these challenges, as well as specific needs such as contraception and pregnancy in female patients. The role of therapies such as cardiovascular drugs to prevent and treat complications, heart transplantation, and mechanical circulatory support remains undetermined. There is a clear need for consensus on how best to follow up patients with Fontan circulation and to treat their complications. This American Heart Association statement summarizes the current state of knowledge on the Fontan circulation and its consequences. A proposed surveillance testing toolkit provides recommendations for a range of acceptable approaches to follow-up care for the patient with Fontan circulation. Gaps in knowledge and areas for future focus of investigation are highlighted, with the objective of laying the groundwork for creating a normal quality and duration of life for these unique individuals.

Prognostic power of cardiopulmonary exercise testing in Fontan patients: a systematic review

Objective

Exercise impairment is common in Fontan patients. Our aim is to systematically review previous literature to determine the prognostic value of exercise capacity in older adolescent and adult Fontan patients with respect to late outcome. Additionally, we reviewed the determinants of exercise capacity in Fontan patients and changes in exercise capacity over time.

Methods

PubMed, CINAHL, Embase, The Cochrane Library and Scopus were searched systematically for studies reporting exercise capacity and late outcome such as mortality, cardiac transplantation and hospitalisation. Studies were eligible for inclusion if more than 30 patients were included and mean age was ≥16 years.

Results

Four thousand and seven hundred and twenty-two studies were identified by the systematic search. Seven studies fulfilled the inclusion and exclusion criteria. The total number of patients was 1664 adult Fontan patients. There were 149 deaths and 35 heart transplantations. All eligible studies were retrospective cohort studies. The correlation between exercise capacity and late outcome was identified, and HRs were reported.

Conclusion

In Fontan patients, the best predictors of death and transplantation were a decline in peak VO₂, heart rate variables and exercise oscillatory ventilation. Peak VO₂ was not strongly predictive of mortality or hospitalisation in Fontan patients. Several variables were strong and independent predictors of hospitalisation and morbidity.

Model-Based Comparison of the Normal and Fontan Circulatory Systems-Part III

BACKGROUND

For patients with the Fontan circulatory arrangement, angiotensin-converting enzyme inhibition, guanylate cyclase activation, phosphodiesterase 5 inhibition, and endothelin receptor antagonism have so far resulted in little or no improvement in [Formula: see text] or peak cardiac index (CI), suggesting that our understanding of the factors that most impact the exercise hemodynamics is incomplete.

METHODS

To facilitate comparisons with clinical reports of the exercise performance of preadolescent Fontan patients, we rescaled our previously reported computational models of a two-year-old normal child and similarly aged Fontan patient, extended our Fontan model to capture the nonlinear relationship between flow and resistance quantified from previous computational fluid dynamic analyses of the total cavopulmonary connection (TCPC), and added respiration as well as skeletal muscle contraction.

RESULTS

(1) Without respiration, the computational model for both the normal and the Fontan cannot attain the values for CI at peak exercise reported in the clinical literature, (2) because flow through the TCPC is much greater during inspiration than during expiration, the effect on the CI of the dynamic (flow-related) TCPC resistance is much more dramatic during exercise than it is in breath-hold mode at rest, and (3) coupling breathing with skeletal muscle contraction leads to the highest augmentation of cardiac output, that is, the skeletal muscle pump is most effective when the intrathoracic pressure is at a minimum-at peak inspiration.

CONCLUSIONS

Novel insights emerge when a Fontan model incorporating dynamic TCPC resistance, full respiration, and skeletal muscle contraction can be compared to the model of the normal.

Relationship Between Habitual Exercise and Performance on Cardiopulmonary Exercise Testing Differs Between Children With Single and Biventricular Circulations

Increasing habitual exercise has been associated with improved cardiopulmonary exercise testing (CPET) performance, specifically maximal oxygen consumption in children with operatively corrected congenital heart disease. This has not been studied in children following Fontan palliation, a population in whom CPET performance is dramatically diminished. A single-center cross-sectional study with prospective and retrospective data collection was performed that assessed habitual exercise preceding a clinically indicated CPET in children and adolescents with Fontan palliation, transposition of the great arteries following arterial switch operation (TGA), and normal cardiac anatomy without prior operation. Data from contemporaneous clinical reports and imaging studies were collected. The association between percent predicted VO_2max and habitual exercise duration adjusted for known covariates was tested. A total of 175 subjects (75 post-Fontan, 20 with TGA, and 80 with normal cardiac anatomy) were enrolled. VO_2max was lower in the Fontan group than patients with normal cardiac anatomy (p < 0.0001) or TGA (p < 0.0001). In Fontan subjects, both univariate and multivariate analysis failed to demonstrate a significant association between habitual exercise and VO_2max (p = 0.6), in sharp contrast to cardiac normal subjects. In multivariate analysis, increasing age was the only independent risk factor associated with decreasing VO_2max in the Fontan group (p = 0.003). Habitual exercise was not associated with VO_2max in subjects with a Fontan as compared to biventricular circulation. Further research is necessary to understand why their habitual exercise is ineffective and/or what aspects of the Fontan circulation disrupt this association.

Assessing ST Segment Changes and Ischemia During Exercise Stress Testing in Patients with Hypoplastic Left Heart Syndrome and Fontan Palliation

While exercise stress testing (EST) is an important tool, little is known about its use for determining ischemia in patients with hypoplastic left heart syndrome (HLHS) and Fontan palliation. We sought to determine the frequency of ST segment changes during EST in HLHS patients after Fontan and examine results of further testing performed in response to ST changes. A single-center chart review of HLHS patients post-Fontan from January 1995 to December 2012 was performed. Data collected included demographics, indications for EST, resting electrocardiogram findings, EST and echocardiogram results and outcomes. ESTs were evaluated for ST segment changes concerning for ischemia. Results of additional testing performed based on concerning EST findings were collected. Twenty-seven patients underwent 64 ESTs (mean 2.4 ESTs/patient). Median age at first EST was 9.6 years (range 6.2-16.4). EST was concerning for ischemia in 13 patients (48 %) on 25 (39 %) ESTs. Based on EST results, two patients had stress sestamibi testing, two underwent coronary angiography, and one had both. No reversible perfusion defects or coronary artery obstructions were demonstrated. No patient who underwent EST has died. ST segment depression was not associated with ventricular dysfunction prior to EST or at the end of follow-up (p > 0.05). In patients with HLHS post-Fontan palliation, ST segment depression on EST is common. In patients who underwent further testing, no evidence of ischemia or coronary abnormalities was found. Additional testing may not be necessary in all patients.

The prevalence of arrhythmias, predictors for arrhythmias, and safety of exercise stress testing in children

Exercise testing is commonly performed in children for evaluation of cardiac disease. Few data exist, however, on the prevalence, types of arrhythmias, predictors for arrhythmias, and safety of exercise testing in children. A retrospective review of all patients ≤21 years undergoing exercise testing at our center from 2008 to 2012 was performed. Patients with clinically relevant arrhythmias were compared to those not experiencing a significant arrhythmia. 1,037 tests were performed in 916 patients. The mean age was 14 ± 4 years, 537 (55 %) were male, 281 (27 %) had congenital heart disease, 178 (17 %) had a history of a prior arrhythmia, and 17 (2 %) had a pacemaker or ICD. 291 (28 %) patients had a rhythm disturbance during the procedure. Clinically important arrhythmias were noted in 34 (3 %) patients and included: 19 (1.8 %) increasing ectopy with exercise, 5 (0.5 %) VT, 5 (0.5 %) second degree AV block, 3 (0.3 %) SVT, and 2 (0.2 %) AFIB. On multivariate logistic regression, variables associated with the development of clinically relevant arrhythmias included severe left ventricular (LV) dysfunction on echo (OR 1.99, CI 1.20-3.30) and prior history of a documented arrhythmia (OR 2.94, CI 1.25-6.88). There were no adverse events related to testing with no patient requiring cardioversion, defibrillation, or acute anti-arrhythmic therapy. A total of 28 % of children developed a rhythm disturbance during exercise testing and 3 % were clinically important. Severe LV dysfunction and a history of documented arrhythmia were associated with the development of a clinically important arrhythmia.

Exercise capacity in the Fontan circulation

The Fontan operation can create a stable circulation from childhood through early adulthood. However, the absence of a sub-pulmonary pumping chamber leads to a physiology in which exercise capacity is limited and decreases with age starting in adolescence. The limitation in exercise capacity is more pronounced at peak levels of exercise, but is still present during more modest levels of activity. The underlying causes of exercise impairment relate to both central cardiovascular factors (oxygen delivery) and peripheral factors (oxygen extraction). Interventions to improve cardiac preload and to improve lean muscle mass may help to improve exercise capacity and, perhaps, will alter the "natural history" of the progressive decline.

Health related quality of life of children with rheumatic heart diseases: reliability of the Brazilian version of the Pediatric Quality of Life Inventory™ Cardiac Module scale

BACKGROUND

This study aimed to translate the 'Pediatric Quality of Life Inventory™ (PedsQL™ 3.0) Cardiac Module' into Portuguese, adapt it to Brazilian culture, and assess its psychometric properties (validity and reproducibility), and to calculate health-related quality of life scores on the PedsQL 4.0 and PedsQL™ 3.0 Cardiac Module Scales for a group of patients 5 to 18 years old with rheumatic heart disease.

METHODS

The methods suggested by the authors of the original version of the questionnaire included 1) translation by an expert panel; 2) translation back into English and revision by the authors of the original version; 3) pilot study with seven children and parents in each of three age ranges (5 to 7, 8 to 12, and 13 to 18 years old); and 4) assessment of the measurement properties. In this stage, the PedsQL™ 3.0 Cardiac Module and the PedsQL 4.0 Generic Scale were applied to a sample comprising 109 children and adolescents with rheumatic heart disease and their parents or caregivers. The version for parents or caregivers was administered separately on the same day.

RESULTS

The values of Cronbach's alpha for all scales assessed in the questionnaire (heart problems and treatment [symptoms], problems with perceived physical appearance, treatment anxiety, cognitive problems, and communication problems) varied from 0.6 to 0.8, indicating good internal consistency. Correlation was found between the scores for the Cardiac Module and the Generic Scale (0.36-0.86), demonstrating convergent validity (Spearman's correlation coefficient, p < 0.01). The symptoms, problems with perceived physical appearance, and cognitive and communication problem domains were able to distinguish between groups of patients with mild and moderate/severe heart disease (Student's t-test, p < 0.05). The intraclass correlation of the interobserver reproducibility was adequate (0.76 to 0.94 among the patients [children/adolescents] and 0.76 to 0.84 among their caregivers). The correlation between the patients' scores and their parents' scores varied from 0.50 to 0.86 (Pearson's correlation coefficient, p < 0.01).

CONCLUSIONS

The Brazilian version of the PedsQL™ 3.0 Cardiac Module was shown to be reliable. The application of this questionnaire in practice will be very useful for all professionals charged with the care of children and adolescents with heart diseases.

Habitual exercise correlates with exercise performance in patients with conotruncal abnormalities

Cardiopulmonary exercise testing (CPET), particularly maximal oxygen consumption (VO2max), has been used to assess the outcome for patients with palliated congenital heart disease (CHD). Small studies correlating VO2max with noninvasive imaging measures of ventricular function have led to the hypothesis that VO2max reflects cardiac performance. In other settings, physical training is associated with increased VO2max. The authors hypothesized that habitual exercise correlates with VO2max to a greater degree than ventricular function in a relatively healthy cohort of patients with palliated CHD. The habitual exercise behavior of 208 subjects with conotruncal abnormalities (tetralogy of Fallot, truncus arteriosus, and interrupted aortic arch) at the time of previously performed, study-based CPET and cardiac magnetic resonance imaging (CMR) were retrospectively assessed via questionnaire. The association of VO2max with habitual exercise duration and CMR measures of ventricular function was tested. Of 208 subjects, 89 (43 %) completed questionnaires, and 78 % of the 89 patients had a concurrent CMR. The mean VO2max was 76 ± 21 % of that predicted. The CMR-assessed left ventricular ejection fraction was 67.6 ± 7.4 %. The hours of habitual exercise per week correlated with VO2max (p < 0.001; r (2) = 0.14). No association was found between right and left ventricular ejection fraction, cardiac index, or right ventricular end-diastolic volume and VO2max. In this study, VO2max correlated with habitual exercise to a greater degree than CMR measurements of ventricular function. These findings highlight the importance of considering the contribution of noncardiac factors when exercise data in both clinical and research settings are interpreted. The contribution of these factors to clinical outcomes deserves further study.

Cross-sectional study of motor development among children after the Fontan procedure

OBJECTIVES

To determine the gross motor skills of school-aged children after the Fontan procedure and compare the locomotor and object control skills with normative data. Study design This study followed a cross-sectional design.

SETTING

This study was based on hospital outpatient visit, with accelerometry conducted at home. Patients This study included 55 patients, including 22 girls in the age group of 6-10 years, 5.1 years after Fontan. Main outcome measures Test of Gross Motor Development - Version 2, daily activity by accelerometer, medical history review, child and parent perceptions of activity.

RESULTS

Being involved in active team sports increased locomotor percentile score by 10.3 points (CI: 4.4, 16.1). Preference for weekend outdoor activities (6.9, CI: 2.0, 11.8), performing at least 30 minutes of moderate-to-vigorous physical activity daily (24.5, CI: 7.3, 41.8), and reporting that parents seldom criticise the child's physical activity (21.8, CI: 8.9, 34.8) were also associated with higher locomotor percentile scores (p < 0.01). Object control percentile scores were higher (p < 0.03) with involvement in formal instruction (5.9, CI: 1.1, 10.6) and being restricted to "activities within comfortable limits" (27.6, CI: 7.7, 47.5). Older chronological age (r = 0.28), a more complicated medical history (r = 0.36), and older age at Fontan (r = 0.28) were associated with greater skill delay (p < 0.04).

CONCLUSIONS

Children after Fontan attain basic motor skills at a later age than their peers, and deficits continue for more complex skills as age increases, suggesting a need for longitudinal monitoring of gross motor skill development through the elementary school years. Future research might investigate whether a gross motor skill rehabilitation programme can provide these children with the motor skills needed to successfully participate in a physically active lifestyle with peers.

Functional capacity following univentricular repair--midterm outcome

OBJECTIVE

Previous studies have seldom compared functional capacity in children following Fontan procedure alongside those with Glenn operation as destination therapy. We hypothesized that Fontan circulation enables better midterm submaximal exercise capacity as compared to Glenn physiology and evaluated this using the 6-minute walk test.

DESIGN AND PATIENTS

Fifty-seven children aged 5-18 years with Glenn (44) or Fontan (13) operations were evaluated with standard 6-minute walk protocols.

RESULTS

Baseline SpO(2) was significantly lower in Glenn patients younger than 10 years compared to Fontan counterparts and similar in the two groups in older children. Postexercise SpO(2) fell significantly in Glenn patients compared to the Fontan group. There was no statistically significant difference in baseline, postexercise, or postrecovery heart rates (HRs), or 6-minute walk distances in the two groups. Multiple regression analysis revealed lower resting HR, higher resting SpO(2) , and younger age at latest operation to be significant determinants of longer 6-minute walk distance. Multiple regression analysis also established that younger age at operation, higher resting SpO(2) , Fontan operation, lower resting HR, and lower postexercise HR were significant determinants of higher postexercise SpO(2) . Younger age at operation and exercise, lower resting HR and postexercise HR, higher resting SpO(2) and postexercise SpO(2) , and dominant ventricular morphology being left ventricular or indeterminate/mixed had significant association with better 6-minute work on multiple regression analysis. Lower resting HR had linear association with longer 6-minute walk distances in the Glenn patients.

CONCLUSIONS

Compared to Glenn physiology, Fontan operation did not have better submaximal exercise capacity assessed by walk distance or work on multiple regression analysis. Lower resting HR, higher resting SpO(2) , and younger age at operation were factors uniformly associated with better submaximal exercise capacity.

The oxygen uptake efficiency slope in children with congenital heart disease: construct and group validity

OBJECTIVE

The oxygen uptake efficiency slope (OUES) has been proposed as an independent and objective alternative to the peak oxygen uptake (VO(2peak)), which does not require maximal exercise. The aim of this study was to investigate the construct and group validity of the OUES in children with congenital heart disease (CHD).

METHODS

Thirty-one patients with CHD, of which 16 patients (mean age ± SD 11.2 ± 2.7 years) with a Fontan repair and 15 patients (mean age ± SD 13.2 ± 3.6 years) with surgical repair of tetralogy of Fallot (ToF) completed a symptom-limited cardiopulmonary exercise test. The OUES was calculated and normalized for body surface area at three different exercise intensities: (1) using 100% of the exercise data; (2) using the first 75% of the exercise data; and (3) using exercise data up to the ventilatory threshold (VT). Furthermore, peak oxygen uptake (VO(2peak)), VT, ventilatory efficiency (V(E)/VO(2)-slope), and ventilatory drive (V(E)/VCO(2)-slope) were calculated and compared with values of 46 healthy children (mean age ± SD 12.2 ± 2.4 years).

RESULTS

In all three groups, the OUES values determined at the three different exercise intensities were not significantly different from each other. Moreover, the OUES was significantly reduced in the children with CHD, with significantly lower values in the Fontan patients compared to ToF. Strong correlations were found between the OUES and both the VO(2peak) and VT in Fontan and ToF patients.

DISCUSSION

The OUES provides a valid measure of cardiopulmonary fitness in children with CHD, which is independent of exercise intensity and strongly correlated with VO(2peak) and VT (construct validity). Furthermore, the OUES is capable of differentiating between healthy children and children with CHD and between Fontan and ToF patients (group validity). Therefore, the OUES may be a valid, effort-independent parameter of cardiopulmonary fitness in children with CHD.

Relation of systemic venous return, pulmonary vascular resistance, and diastolic dysfunction to exercise capacity in patients with single ventricle receiving fontan palliation

Fontan patients have a reduced exercise capacity, primarily owing to limitations in the ability to augment pulmonary blood flow and stroke volume. To date, the mechanism of peak exercise pulmonary blood flow restriction has not been elucidated. We performed a single-center, prospective, crossover trial of supine and upright exercise in Fontan patients and healthy controls to determine the mechanisms of exercise limitation in the Fontan-palliated patient. A total of 29 Fontan patients and 16 control subjects completed the protocol. The duration of exercise, percentage of predicted peak oxygen consumption (VO(2)) and peak work were reduced in the Fontan group, regardless of posture (p < or = 0.03). The percentage of predicted oxygen pulse, a surrogate for pulmonary stroke volume, was not increased with supine posture in the Fontan cohort (upright, 82.3 + or - 18.8% vs supine, 82.4 + or - 19.7%; p = 0.6). In both groups, the percentage of predicted peak VO(2) was lower with supine exercise than with upright exercise (p < or =0.002). Diastolic dysfunction was present in 57% of the Fontan patients and was associated with a reduced percentage of predicted peak VO(2) (p = 0.04) and supine peak work (p = 0.008). Six Fontan patients who underwent supine exercise with indwelling catheters failed to demonstrate the expected decrease in pulmonary vascular resistance characteristically seen with peak exercise (at rest, 2.8 + or - 0.7 mm Hg/L/min/m(2) vs at peak, 2.8 + or - 0.9 mm Hg/L/min/m(2); p = 0.9). In conclusion, supine exercise in Fontan patients does not result in an increased VO(2) or oxygen pulse, suggesting that inadequate venous return might not be the primary limitation of exercise capacity in this population. Diastolic dysfunction and relatively excessive peak exercise pulmonary vascular resistance might be more important factors in Fontan exercise limitation.

Quality-of-life concerns differ among patients, parents, and medical providers in children and adolescents with congenital and acquired heart disease

OBJECTIVES

Mortality rates in pediatric patients with heart disease have decreased dramatically in recent decades, resulting in an increasing number of survivors with morbidities that impact quality of life. The purpose of this study was to assess and compare how heart disease affects the quality of life of the pediatric cardiac patient from the perspectives of the patient, parent, and health care provider.

METHOD

Individual focus groups were conducted with children (8-12 years of age) with heart disease, adolescents (13-18 years of age) with heart disease, parents of children with heart disease, parents of adolescents with heart disease, and health care providers of pediatric patients with heart disease. A structured focus group technique was used to develop a list of potential items that might affect quality of life. Participants chose the 5 most important items from the list. These items were then categorized into preidentified dimensions (physical, psychological, social, school, and other). The percentages of the total votes for all items were calculated and distributions of responses across dimensions within group and within dimension across groups were reported and compared qualitatively.

RESULTS

Patient and parent groups identified similar items as important. Providers identified different items. The physical limitation item received the largest percentage of total votes in all groups (9%-20%). Analysis across dimension revealed that those items related to the physical dimension received the highest percentage of total votes among all groups (30.2%-51.2%). Analysis within dimension revealed that patients endorsed items in the physical dimension more frequently than parents or providers. Within the psychological dimension, the children selected the fewest items relative to all other groups (7.2% vs 21.3%-37.8%), whereas health care providers endorsed these items more frequently than patients or parents (child or parent of child groups 7.2%-21.3% vs health care provider group 28.8%; adolescent or parent of adolescent groups 29.6% vs health care provider group 37.8%). Differences were noted between the child and adolescent groups in the psychological (child versus adolescent: 7.2% vs 29.6%) and school (child versus adolescent: 11.2% vs 2.1%) dimensions.

CONCLUSIONS

Patients and parents generally agreed on how heart disease affects the quality of life of children and adolescents, whereas health care providers had a different opinion.

Decreased exercise performance with age in children with hypoplastic left heart syndrome

OBJECTIVE

Children born with hypoplastic left heart syndrome (HLHS) may experience cardiac dysfunction after staged surgery or transplantation, which may worsen with age. We examined the hypothesis that exercise testing can address cardiovascular capacity and suggest interventions to improve quality of life.

STUDY DESIGN

Children with HLHS > or = 8 years old performed treadmill or bicycle ergometric testing at 4 centers. Results were compared with norms for age and sex.

RESULTS

Of the 42 participants, the mean age was 12.9 years (range, 8.5-17.0 years), 64% were boys, 20 had staged surgery, and 34 completed metabolic assessment. The percent of predicted maximal oxygen uptake (mVO2) was higher in younger children. Children aged 8 to 12 years achieved 70% of predicted mVO2; children aged 13 to 17 years achieved 60% of predicted mVO2 (P = .02). The percent of predicted peak heart rate trended higher in younger patients (83% versus 75%, P = .07). Electrocardiographic changes were more common in older children. In treadmill testing, patients who had a transplant had better exercise performance than patients who underwent staged surgery in percent of predicted exercise time (82% versus 54%, P < .0001) and peak rate-pressure product (241 x 10(3) versus 195 x 10(3), P = .02). The percent of predicted mVO2 did not differ between patients who had a transplant (66%) and patients who underwent staged surgery (61%, P = .25).

CONCLUSION

Children with HLHS showed considerable age-related decline in exercise performance, regardless of surgical strategy.

Exercise limitation in patients with Fontan circulation: a review

The aim of the current literature study was to perform a literature review of the factors contributing to exercise limitation and physiological response to exercise in patients with Fontan circulation. In patients with Fontan circulation, peak oxygen uptake ranged from about 14.4 to 32.3 ml/min/kg, and showed a slowed acceleration in the kinetics of oxygen uptake at the onset of exercise. Peak heart rate during exercise was decreased to an average of 153 +/- 10 bpm and arterial oxygen saturation was also decreased at peak exercise, with an average of 89.5 +/- 1.94%. Cardiac output was subnormal, owing to reduced stroke volume, heart rate response and affected pulmonary venous return. Ventilatory anaerobic threshold was below normal values. Moreover, the ventilatory equivalent for carbon dioxide was found to be higher. Patients with Fontan circulation possess a unique physiological response to exercise. Although there is a wide range in exercise capacity among patients, all patients have reduced tolerance to exercise. Cardiac, pulmonary, and muscular factors might play a role in reduced exercise capacity and this distinct response to exercise.

Physical activity levels in children and adolescents are reduced after the Fontan procedure, independent of exercise capacity, and are associated with lower perceived general health

OBJECTIVES

To determine physical activity levels in paediatric patients who underwent the Fontan procedure, and their relationship to functional status and exercise capacity.

STUDY DESIGN

We studied 147 patients (ages 7-18 years) at a median of 8.1 years after Fontan, as part of the Pediatric Heart Network cross-sectional study of Fontan survivors. Assessment included medical history, self-reported physical activity, parent-completed Child Health Questionnaire (CHQ), cardiopulmonary exercise testing and physical activity level measured by accelerometry (MTI Actigraph).

RESULTS

Measured time spent in moderate and vigorous activity was markedly below normal at all ages, particularly in females, and was not significantly related to self-reported activity levels, or to maximum Vo2, Vo2 at anaerobic threshold or maximum work rate on exercise testing. Lower measured activity levels were significantly related to lower perceived general health but not to self-esteem, physical functioning, social impact of physical limitations or overall physical or psychosocial health summary scores. Reduced exercise capacity was more strongly related than measured activity levels to lower scores in general health, self-esteem and physical functioning.

CONCLUSIONS

Physical activity levels are reduced after Fontan, independent of exercise capacity, and are associated with lower perceived general health but not other aspects of functional status.

Health-related quality of life: A closer look at related research in patients who have undergone the Fontan operation over the last decade

The advancements in surgical technique and perioperative care have significantly improved the survival of children with single ventricle (SV) congenital heart disease (CHD) over the past decade. The population who have undergone the Fontan operation are growing into adulthood and facing many unique challenges. Past research has focused on functional and neurodevelopmental outcomes with inferences made to health-related quality of life (HRQOL). With the population who have undergone the Fontan operation surviving into adulthood, little research has been directed toward the self-report of HRQOL in adolescents and young adults after surgical palliation. Questions still remain on how these patients will transition into adulthood and whether they will live normal productive lives. This article reviews the literature related to HRQOL in the SV subgroup of CHD. In addition, an overview of newly developed disease-specific HRQOL instruments is presented as well as limitations and future research in HRQOL of the SV Fontan population.

Exercise capacity and impact of exercise training in patients after a Fontan procedure: a review

After a successful Fontan procedure, children and adolescents should improve their exercise capacity. However, several studies have shown that these children have a reduced maximal oxygen consumption compared with healthy children. The lower exercise performance in these patients was mainly explained by a reduced cardiorespiratory functional capacity. However, it has recently been reported that the lower exercise performance may also be related to altered skeletal muscle function. Moreover, exercise training had a beneficial impact on several parameters related to exercise tolerance in these patients. The main studies supporting these observations are reviewed, with a focus on the physiological adaptation and limitation of the exercise performance as well as the benefits of exercise training in patients after a Fontan procedure.

Reduced pulmonary function in children with the Fontan circulation affects their exercise capacity

Most children with functionally univentricular hearts nowadays are treated surgically by creating a total cavopulmonary connection. In the resulting Fontan circulation, the venous return and the pulmonary arterial bed are coupled in series, bypassing the heart. This gives the potential for interaction between the abnormal circulation and function of the lungs. In this study, we investigated the pattern of impairment of pulmonary function, and its relation to decreased exercise capacity. We performed spirometry in 33 (85 percent) of 39 eligible Norwegian children, aged from 8 to 16, with a total cavopulmonary connection, along with whole body plethysmography, the carbon monoxide single breath test, and a peak treadmill exercise test. The single breath test showed a mean corrected diffusing capacity of 66.5 percent of predicted, giving a z score of minus 2.88. The mean residual volume measured by whole body plethysmography was 146.8 percent, equivalent to a z score of 2.46, whereas the mean residual volume measured by the single breath test was 102.4 percent of predicted, this being the same as a z score of 0.43. The mean peak treadmill exercise test was 70.0 percent of predicted, equivalent with a z score of minus 3.07. Mean forced vital capacity was 85.7 percent of predicted, the equivalent z score being minus 0.92. Lung function correlated with the peak treadmill exercise test. We have shown, therefore, that children with the Fontan circulation have reduced diffusing capacity, possibly caused by the abnormal circulation through the lungs. The difference between residual volume measured by plethysmography and the single breath test implies trapping of air. The correlation of parameters for lung function with peak consumption of oxygen during exercise indicates that the abnormalities of pulmonary function may affect physical capacity.

Impact of exercise training on muscle function and ergoreflex in Fontan patients: a pilot study

BACKGROUND

Several studies have demonstrated persistent reduced exercise capacity in Fontan patients even after surgical intervention. The purpose of this study was to evaluate if the skeletal muscle function of these patients is abnormal, if it correlates with exercise tolerance and if it can be improved by exercise training.

METHODS

We evaluated the functional capacity of seven patients who underwent Fontan procedure (age:16+/-5 years, mean+/-SD) and seven healthy children (19+/-7 years) paired for age, sex, height and weight. Evaluation included pulmonary evaluation, neuromuscular function and exercise tolerance. Secondly, an 8-week exercise training program was performed by five of these patients.

RESULTS

The ergoreflex contribution to absolute diastolic blood pressure was higher (12.5+/-4.8 vs. 5.6+/-4.2 mmHg; p=0.04) in Fontan patients vs. healthy subjects whereas a trend was encountered regarding the ergoreflex contribution to absolute systolic blood pressure (9.0+/-7.0 vs. 0.4+/-9.0 mmHg; p=0.09). Furthermore, time to fatigue of the non-dominant forearm muscles was shorter in Fontan patients vs. healthy subjects (431+/-290 vs. 847+/-347 s; p=0.03). Following exercise training, there was a significant reduction of the ergoreflex contribution to absolute values of systolic blood pressure (9.8+/-0.9 vs. 0.3+/-2.7 mmHg; p<0.05). There was an association between muscle strength and VO2 peak in Fontan patients (upper limb: r=0.895; p<0.01; lower limb: r=0.838; p<0.05, respectively).

CONCLUSIONS

Skeletal muscle function in Fontan patients is abnormal which may have an impact in the reduced exercise tolerance encountered in these patients. Exercise training may have beneficial impacts on the skeletal muscle function in this population.

Late outcomes in patients with surgically treated congenital heart disease

Optimizing late outcomes should be the end result of improvements in medical and surgical care for congenital heart disease (CHD). In addition to mortality, significant morbidities after surgery for CHD need to be considered. These include the need for reintervention, cardiovascular complications, exercise limitations, neurocognitive morbidities, effects on pregnancy, difficulty obtaining insurance, need for chronic medications, and impaired functional status and quality of life. Long-term outcome studies are difficult to perform, and their interpretation is complicated by intervening changes in management. Specific discussion of long-term follow-up of tetralogy of Fallot, D-transposition of the great arteries, and hypoplastic left heart syndrome illustrates the myriad management changes over the last three decades, the challenges in predicting outcomes for recent patients, and the need for ongoing initiation of long-term follow-up studies.

Exercise testing in pediatrics

This article discusses exercise physiology and its application in the pediatric population. This article discusses exercise physiology and its application in the pediatric population. The authors briefly review the normal physiologic response to exercise. They then discuss populations in which exercise testing is most useful, the indications and contraindications for graded exercise, and the usual parameters that are measured during testing. Finally, the authors review some of the recent data on exercise performance in specific pediatric populations.

Midterm surgical results of total cavopulmonary connection: clinical advantages of the extracardiac conduit method

OBJECTIVE

We evaluated the midterm surgical outcomes of intra-atrial lateral tunnel and extracardiac conduit total cavopulmonary connection to clarify the clinical superiority.

METHODS

Patients (n = 167) underwent total cavopulmonary connection (88 with lateral tunnel and 79 with extracardiac conduit) from November 1991 to March 1999. Survival, incidence of reoperation and late complications, exercise tolerance, hemodynamic variables, and plasma concentration of natriuretic peptide type A were compared. In the lateral tunnel group, time-related change in lateral tunnel size was investigated for its relationship to postoperative arrhythmias.

RESULTS

The 8-year survival was 93.2% in the lateral tunnel group and 94.9% in the extracardiac conduit group. Seven reoperations were performed in the lateral tunnel group but none in the extracardiac conduit group. Supraventricular arrhythmias developed in 14 patients (15.9%) in the lateral tunnel group and in 4 patients (5.1%) in the extracardiac conduit group (P =.003). Freedom from cardiac-related events was 72.5% in the lateral tunnel group and 89.8% in the extracardiac conduit group at 8 years (P =.0098). Hemodynamic variables and exercise tolerance were similar in both groups but plasma natriuretic peptide type A concentration, a parameter of atrial wall tension, was higher in the lateral tunnel group. In the lateral tunnel group, intra-atrial tunnel size increased by 19.4% during the 44.2-month interval and the percent increase in tunnel size was an independent predictor of supraventricular arrhythmias.

CONCLUSIONS

The midterm survival, hemodynamic variables, and exercise tolerance were similar and satisfactory in both lateral tunnel and extracardiac conduit groups; however, the incidence of cardiac-related events was significantly less frequent in the extracardiac conduit group. In the lateral tunnel group, careful observation is required to monitor the relationship of the dilating tendency of the intra-atrial tunnel and the development of late complications.

Lung function and aerobic capacity in adult patients following modified Fontan procedure

OBJECTIVE

To examine cardiopulmonary performance in 52 adult patients with a Fontan circulation.

DESIGN

Retrospective cohort study. Values of maximum oxygen uptake (VO(2)max), maximum heart rate (HRmax), forced vital capacity (FVC), and forced expiratory volume in one second (FEV(1)) were compared with predictive values for different age groups. Patients were further subdivided into those with a pulmonary artery connection (RA-PA) or right atrium to right ventricle conduit (RA-RV).

RESULTS

At late follow up (median 10 years, range 1 to 26 years), patients with Fontan circulation had greatly diminished VO(2)max, HRmax, FVC, and FEV(1) compared with predicted values. Early age at surgery had a positive impact on aerobic capacity. The FEV(1):FVC ratio indicated restrictive lung function. No differences were found with respect to any variable between patients with RA-PA connections and those with RA-RV connections.

CONCLUSIONS

Patients with a Fontan circulation have greatly diminished values of aerobic capacity and a restrictive pattern of lung function. Patients with an early surgical procedure obtained higher values of VO(2)max. The theoretical benefits of including the right ventricle in a Fontan circulation were not apparent.

Similarities and differences in the exercise performance of patients after a modified Fontan procedure compared to patients with complete transposition following a Senning operation

OBJECTIVE

To investigate cardiopulmonary performance in patients after a Fontan procedure, comparing it to patients following a Senning operation.

METHODS

We studied 21 children, with a mean age of 11.1 years, after a total cavopulmonary anastomosis, comparing them to 13 with complete transposition after a Senning procedure, having a mean age of 11.8 years, and 21 control subjects with a mean age of 11.2 years. All were tested on a bicycle ergospirometer.

RESULTS

Peak consumption of oxygen, maximal work rate, peak oxygen pulse and endexpiratory pressure of carbon dioxide at a work rate of 1.5 Watt/kg were lowest in patients with a modified Fontan procedure, and highest in the control group (p < or = 0.0278). Production of carbon dioxide, and minute ventilation at a work rate of 1.5 Watt/kg, was highest in the patients after Fontan procedure, and lowest in the healthy subjects (p < or = 0.0163). Production of carbon dioxide per single breath was lower in those having a Fontan procedure (28.9 ml) than in the two other groups (35.1 ml; p = 0.0243). The tidal volume showed no significant differences between the three groups.

CONCLUSIONS

The reaction to exercise was identical qualitatively in both groups of patients, and comparable to the behaviour of patients with chronic heart failure. Quantitatively, the results of the patients following a Senning procedure lay between those of control subjects and those who had undergone a Fontan operation. The only exception was dead space ventilation, where the patients after a Fontan procedure differed from the two other groups because of their increased ventilation-perfusion mismatch.