Muscle function in adults with congenital heart disease

Investigation of Community Integration in Adults with Congenital Heart Disease Within the Scope of International Classification of Functioning, Disability, and Health

The number of adults living with congenital heart disease continues to rise, emphasizing the need to understand the challenges they encounter to enhance disease management. This study aimed to evaluate adults with CHD using the International Classification of Functioning (ICF) framework and explore factors associated with community integration. Holistic assessments were conducted encompassing all dimensions of the ICF framework, including Body Structures (echocardiography and electrocardiography findings), Body Functions (6-Minute Walk Test, Muscle Strength, Hand Grip Strength, and Fatigue Severity Scale), Activity-Participation (International Physical Activity Questionnaire, Multidimensional Quality of Life Scale, and Community Integration Questionnaire), and Environmental-Personal factors (Depression, Anxiety, and Stress Scale- 21, and Physical Activity Barriers Scale). Pearson correlation analysis was conducted to examine the relationships between community integration and other parameters, with variables showing significant correlations included in the multiple linear regression analysis. The mean age of 42 CHD participants was 24.61 ± 7.27 years. The Community Integration Questionnaire correlated with the Physical Activity Barriers Scale (r = 0.310, p = 0.046), Multidimensional Quality of Life Scale (r = 0.441, p = 0.003), and 6-min walk test (r = 0.364, p = 0.021). "Access to health personnel," a sub-dimension of the Multidimensional Quality of Life Scale, and 6-min walk test distance predicted the Community Integration Questionnaire score, explaining 30.7% of its variance (r = 0.554; r2 = 0.307; F = 8.197; p = 0.001). The findings suggest that community integration in individuals with CHD is linked to body function, activity-participation, and environmental-personal factors. This study highlights the importance of evaluating patient-reported outcome measures in the domain of community integration, especially considering the shifting demographics of congenital heart disease.

Health-related quality of life in adults with Marfan syndrome

BACKGROUND AND AIM

Marfan syndrome is a rare genetic connective tissue disorder. Research on health-related quality of life in Swedish patients is lacking. We aimed to examine health-related quality of life in patients with Marfan syndrome with respect to reference values, sex, and age.

METHODS

Using the registry for adult CHD, Sahlgrenska University Hospital/Östra Hospital, between 1 April 2009 and 31 January 2023, we identified 1916 patients. Of these, we included 33 patients aged ≥18 years who were diagnosed with Marfan syndrome and had completed the 36-item Short-Form Health Survey.

RESULTS

The median age was 32 years (interquartile range 25.5-47.0) and 22 (66.7%) were men. Patients with Marfan syndrome had significantly lower values than reference values for all scales in the Short-Form Health Survey except bodily pain, role-emotional, and the physical component summary score. For both men and women with Marfan syndrome, vitality was the subscale with the greatest percentage difference in comparison with healthy reference values (82% in women and 73% in men). Furthermore, men reported significantly higher vitality levels than women (62.5 points, interquartile range 43.8-75.0 vs. 35 points, interquartile range 10.0-65.0, p = 0.026).

CONCLUSION

Adults with Marfan syndrome in Sweden showed lower health-related quality of life levels in comparison with reference values for most Short-Form Health Survey scales, and there were differences between patients with Marfan syndrome in terms of sex and age.

Exploring frailty: muscle strength, functional capacity, activities of daily living and cognition in adult congenital heart disease

PURPOSE

The study aimed to assess frailty in adults with congenital heart disease (ACHD) and to compare muscle strength, functional capacity, activities of daily living (ADL), and cognition between frail and non-frail ACHD patients.

MATERIALS AND METHODS

A cross-sectional study design was used. Sixty people with ACHD aged between 18 and 45 years were included. Frailty was determined according to the Fried criteria. Peripheral muscle strength was assessed with a digital dynamometer, functional capacity with the 6-min walk test (6MWT), ADL with the Glittre ADL test, and cognition with the Montreal Cognitive Assessment (MoCA) test.

RESULTS

Frailty was seen in 38.33% (frail = 23 and non-frail = 37) of the participants. In the frail patients, dominant knee extensor strength (p = 0.002), shoulder abductor strength (p = 0.005), 6MWT distance (p = 0.021), and MoCA score (p = 0.005) were significantly lower than those in the non-frail patients. Glittre ADL test (p = 0.002) was significantly higher in the frail patients.

CONCLUSIONS

Muscle strength, functional capacity, ADL, functional mobility, and cognition were lower in the frail participants with ACHD. Early assessment of frailty in ACHD and planning individualized exercise training programs for frail individuals may be a strategy to reduce the impact of frailty on adverse clinical outcomes.

The effects of telerehabilitation in adults with complex biventricular congenital heart conditions: protocol for a multi-centre, randomised controlled trial-CH-FIT

BACKGROUND

Accumulated evidence suggests that exercise training exerts beneficial effects on people with congenital heart conditions. These findings are predominantly derived from small, single-centre exercise trials conducted in outpatient rehabilitation facilities. In recent years, the delivery of exercise interventions remotely has increased through digital communications technology (telerehabilitation). However, very little research to date has been conducted into the efficacy of telerehabilitation in people with a congenital heart condition.

AIMS

To evaluate the effects of a telehealth-delivered exercise intervention in people with a history of a surgical biventricular repair due to a congenital heart condition.

METHODS

One hundred eligible adolescent (≥ 16 years) and adult participants living with a complex biventricular congenital heart condition will be recruited from four Australian sites and randomised to either (1) a 16-week telehealth-delivered combined (aerobic and resistance) exercise training programme of moderate-to-vigorous intensity or (2) usual care (control group), in a 1:1 allocation, with an 8-month follow-up.

OUTCOMES OF INTEREST

The primary outcome will be the change in aerobic capacity expressed as peak oxygen uptake (VO2peak). Secondary outcomes will include changes in vascular function, muscle oxygenation, metabolic profile, body composition and musculoskeletal fitness, neurohormonal activation, neurocognitive function, physical activity levels, dietary and nutritional status, and quality of life. Outcomes will be assessed at baseline, 16 weeks, and 12 months (to determine longer-term maintenance potential).

DISCUSSION

If found to be efficacious, telerehabilitation may be an alternative option for delivering exercise, improving health outcomes, and increasing accessibility to exercise programmes. Efficacy data is required to quantify the clinical significance of this delivery mode of exercise.

TRIAL REGISTRATION

ACTRN12622000050752 Trial registration date: 17 January 2022 Trial registration URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=382635&showOriginal=true&isReview=true Trial registry name: Australian and New Zealand Clinical Trials Registry.

Cancer risk in adult congenital heart disease

Advances in diagnostics and interventional/surgical treatment of patients with congenital heart disease (CHD) over the past several decades, allows a decline in rates of all-cause mortality, with a significant reduction in proportion of infant and childhood deaths with severe forms of CHD. However, the risk of premature death in adults with complex CHD remains elevated. A growing body of evidence has recently described the impact of non-cardiovascular comorbidities such as cancers, on morbidity, health care utilizations and mortality in adult patients with CHD. Aim of this review is to provide an appraisal of the current evidence that report associations between CHD and increased cancer risk in children and adults, and provide an overview of the specific risk factors.

Functional muscle power in the lower extremity in adults with congenital heart disease

Background

We aimed to investigate functional muscular power in the lower extremity in adults with congenital heart disease (ACHD) and compare results with those of healthy persons. Secondarily, we set out to assess muscle power in relation to age, sex, and complexity of ACHD.

Methods

Between 2013 and 2019, 1126 patients attended the ACHD Unit of Sahlgrenska University Hospital/Östra and performed a test battery to determine physical fitness. Of these patients, 559 who performed the Timed-Stands Test (TST)-which requires 10 stands from a chair at the maximal possible speed-were included in the study.

Results

Patients with ACHD performed the TST slower than reference (14.6 s [12.0-18.0] vs. 11.7 s [9.8-14.3], p < 0.001). Men with ACHD performed the TST more rapidly or according to reference in 8% of patients aged 18-39 years, 21% of patients aged 40-65 years, and 55% of patients aged >65 years. Women with ACHD performed the TST more rapidly or according to reference in 21% of patients aged 18-39 years, 56% of patients aged 40-65 years, and 32% of patients aged >65 years. Men with ACHD performed the TST significantly faster than women with ACHD (p < 0.001).

Conclusions

Decreased functional muscle power was observed in patients with ACHD and was most pronounced in patients aged 18-39 years. Decreased muscle power is important to detect and requires further assessment because it may contribute to an increased risk of falling and developing lifestyle related diseases.

Fractures in patients with and without congenital heart disease - A nationwide register-based cohort study

Background

Patients with congenital heart disease (CHD) now live longer; thus, there is a need to assess factors related to ageing in this group. We aimed to determine the incidence and risk of fractures in patients with CHD.

Methods

Data of patients with CHD were retrieved from the National Swedish Patient Register (n = 83,084) and matched according to birth year and sex, with nearly nine controls per patient from the Total Population Register in Sweden (n = 719,447). CHD diagnoses were classified according to complexity, and fractures according to anatomical disposition.

Results

In comparison with controls, lower incidence rate (IRs) per 10,000 person-years were found in male patients (7.59, 95% confidence interval [CI]: 6.92-8.31 vs. 9.29, 95% CI: 9.06-9.53) and female patients (5.73, 95% CI: 5.11-6.40 vs. 6.02, 95% CI: 5.83-6.23) aged 0-17 years with complex CHD. However, the IR of fractures for all patients with CHD was slightly higher than that of controls (7.42 vs. 7.06 per 10,000 person-years). Patients with CHD from the oldest age group (≥60 years) had a 21% increased risk of fractures in comparison with controls without CHD.

Conclusion

We found that younger patients with complex CHD had a decreased risk of fractures compared with controls without CHD. In contrast, older patients with CHD showed a slightly increased risk of fractures. The increased risk of fractures, together with previous reports of decreased physical capacity, increasing age, and the sequent onset of osteoporosis, warrants close attention in the ageing population of patients with CHD.

Endurance training may improve exercise capacity, lung function and quality of life in Fontan patients

Children born with univentricular hearts undergo staged surgical procedures to a Fontan circulation. Long-term experience with Fontan palliation has shown dramatically improved survival but also of a life-long burden of an abnormal circulation with significant morbidity. Many Fontan patients have reduced exercise capacity, oxygen uptake, lung function and quality of life. Endurance training may improve submaximal, but not maximal, exercise capacity, lung function and quality of life. Physical activity and endurance training is also positively correlated with sleep quality. Reviewing the literature and from our single-centre experience, we believe there is enough evidence to support structured individualised endurance training in most young Fontan patients.

The Effects of Physical Inactivity and Exercise at Home in Young Patients with Congenital Heart Disease during the COVID-19 Pandemic

Background: The COVID-19 pandemic had a significant impact on the population’s ability to be physically active. Purpose: Evaluate the effect of the COVID-19 mitigation measures on exercise tolerance in patients with congenital heart disease (CHD). Materials and methods: All subjects (880, 6–18 years old) who performed a stress test at our hospital from October 2020 to February 2021 and had a similar test one year earlier were enrolled. A questionnaire on the degree of physical activity carried out in 2020 concerning the period prior to the pandemic was compiled. Exercise tolerance and the main anthropometric parameters between the first and second tests were compared. Results: 110 subjects (11.9 ± 4.1 years) were included in the study. The percentage of patients engaged in regular physical activity (RPA) decreased significantly during the pandemic (p < 0.001), and BMI increased significantly (p < 0.001), except among the subjects who began RPA during the lockdown, whereas test duration did not decrease significantly overall but increased in this last subgroup (p < 0.05) Conclusions: The COVID-19 lockdown led to a less active lifestyle with a significant increase in BMI in our group of CHD. These data could have negative effects on the risk profile of this population. RPA practiced at home seems to be effective in counteracting such effects.

Effects of Cardiopulmonary Rehabilitation on the Muscle Function of Children with Congenital Heart Disease: A Prospective Cohort Study

Critical medical and surgical advances have led to a shift in the care and management of children with congenital heart disease (CHD). These patients present with muscle deconditioning, which negatively influences their response to exercise, functional capacities, and quality of life. This study evaluates the influence of a cardiopulmonary rehabilitation program (CPRP) on the function of peripheral musculature of children with CHD. A single-center prospective cohort study was designed. Fifteen CHD subjects, between 12 and 16 years of age, with reduced aerobic capacity on a cardiopulmonary exercise test, were included in a three-month, 24-session CPRP. Measurements of the subjects' handgrip strength, biceps brachii and quadriceps femoris strength, and triceps surae fatigue process were collected at the beginning of the program, after completion, and six months after the end of the intervention. A substantial and statistically significant improvement was observed in the subjects' handgrip strength (kg) (p < 0.001), biceps brachii and quadriceps femoris strength (N) (p < 0.001), as well as triceps surae fatigue process (repetitions) (p = 0.018), with a maintenance of the results six months after the intervention. These results suggest that a CPRP could potentially improve the peripheral muscle function of children with CHD. Additional research is needed to confirm and expand on this hypothesis.

Despite reductions in muscle mass and muscle strength in adults with CHD, the muscle strength per muscle mass relationship does not differ from controls

BACKGROUND

Patients with CHD exhibit reduced isometric muscle strength and muscle mass; however, little is known how these parameters relate. Therefore, the aim was to investigate the relation between isometric limb muscle strength and muscle mass for patients in comparison to age- and sex-matched control subjects.

METHODS

Seventy-four patients (35.6 ± 14.3 years, women n = 22) and 74 matched controls were included. Isometric muscle strength in elbow flexion, knee extension, and hand grip was assessed using dynamometers. Lean mass, reflecting skeletal muscle mass, in the arms and legs was assessed with dual-energy x-ray absorptiometry.

RESULTS

Compared to controls, patients had lower muscle strength in elbow flexion, knee extension, and hand grip, and lower muscle mass in the arms (6.6 ± 1.8 kg versus 5.8 ± 1.7 kg, p < 0.001) and legs (18.4 ± 3.5 kg versus 15.9 ± 3.2 kg, p < 0.001). There was no difference in achieved muscle force per unit muscle mass in patients compared to controls (elbow flexion 0.03 ± 0.004 versus 0.03 ± 0.005 N/g, p = 0.5; grip strength 0.008 ± 0.001 versus 0.008 ± 0.001 N/g, p = 0.7; knee extension 0.027 ± 0.06 versus 0.028 ± 0.06 N/g, p = 0.5). For both groups, muscle mass in the arms correlated strongly with muscle strength in elbow flexion (patients r = 0.86, controls, r = 0.89), hand grip (patients, r = 0.84, controls, r = 0.81), and muscle mass in the leg to knee extension (patients r = 0.64, controls r = 0.68).

CONCLUSION

The relationship between isometric muscle strength and limb muscle mass in adults with CHD indicates that the skeletal muscles have the same efficiency as in healthy controls.

Respiratory and peripheral muscle involvement in patients with pulmonary arterial hypertension due to congenital heart diseases

Skeletal and respiratory muscle dysfunction has been previously described in patients with other etiologic subgroups of pulmonary arterial hypertension (PAH) but has never been investigated in patients with PAH due to congenital heart diseases (CHD). This study aims to show the involvement of skeletal and respiratory muscles in these patients. This cross-sectional study included patients with PAH due to CHD and healthy controls. Patients' demographic properties, six-minute walk tests; shoulder abduction, handgrip, knee extension, and ankle dorsiflexion muscle strength, maximum inspiratory (MIP) and expiratory pressures (MEP) were measured. Deltoid, flexor digitorum superficialis, and profundus, tibialis anterior and rectus femoris muscles were visualized with ultrasonography and their cross-sectional areas (CSA) were also measured in both groups. 12 patients and 12 controls were included. Mean MIP was 104.22±32.57 cm H2O for healthy participants while 61.33±29.74 cm H2O for patients (p<0.001). For mean MEP, it was 100.08±26.05 cm H2O in healthy participants and 69.75±39.79 cmH2O in controls (p=0.004). When the strength of skeletal muscles was compared, there were significant differences between the groups in all measurements except for bilateral grip strength. In the correlation analysis, MIP and MEP values showed no significant correlations with clinical parameters. They showed significant moderate correlations with skeletal muscle strength. When CSAs of the muscles were compared, there were significant differences in all measurements except for left FDS and FDP and bilateral rectus femoris. This study showed that in patients with pulmonary arterial hypertension due to CHD, respiratory muscle strength is significantly worse than healthy participants. Patients had also significantly worse skeletal muscle strength except for grip strength.

Post-operative musculoskeletal outcomes in patients with coarctation of the aorta following different surgical approaches

BACKGROUND

The aim of this study was to examine range of motion and muscle function in the upper extremity and spine in patients with coarctation of the aorta (CoA) comparing different surgical approaches.

METHODS

From October 2017 to February 2019, 150 patients were assessed for inclusion. A total of 99 patients (n = 75 CoA, n = 24 control), were included and assessed regarding muscle function, arm length and circumference, and spinal and thoracic mobility.

RESULTS

There were significant differences between the right and left arm in patients with CoA, operated with the subclavian flap technique compared to controls in regards to shoulder flexion (p < 0.001), elbow flexion (p = 0.001), shoulder abduction (p = 0.02), handgrip strength (p = 0.01), length of upper arm (p < 0.001), lower arm (p < 0.001), and of whole arm (p < 0.001), circumference regarding upper arm (p = 0.001), lower arm (p < 0.001), and wrist (p < 0.001). Structural scoliosis was more frequent in patients who had undergone thoracotomy (25.4%) than patients who had not undergone a thoracotomy (5.9%, p = 0.04), and were often located in the thoracic part of the spine.

CONCLUSION

Patients with CoA operated on using the subclavian flap technique have impaired muscle function as well as reduced arm length and circumference. An increased rate of structural scoliosis was found in patients who underwent thoracotomy, in comparison with patients who had not undergone a thoracotomy. Further research is needed to determine whether muscle function impaired by surgical procedures can be improved with exercise.

Enablers and barriers for being physically active: experiences from adults with congenital heart disease

BACKGROUND

In general, adults with congenital heart disease have reduced exercise capacity and many do not reach the recommended level of physical activity. A physically active lifestyle is essential to maintain health and to counteract acquired cardiovascular disease, therefore enablers and barriers for being physically active are important to identify.

AIM

To describe what adults with complex congenital heart diseases consider as physical activity, and what they experience as enablers and barriers for being physically active.

METHODS

A qualitative study using semi-structured interviews in which 14 adults with complex congenital heart disease (seven women) participated. The interviews were analysed using qualitative content analysis.

RESULTS

The analysis revealed four categories considered enablers and barriers - encouragement, energy level, approach and environment. The following is exemplified by the category encouragement as an enabler: if one had experienced support and encouragement to be physically active as a child, they were more positive to be physically active as an adult. In contrast, as a barrier, if the child lacked support and encouragement from others, they had never had the opportunity to learn to be physically active.

CONCLUSION

It is important for adults with congenital heart disease to have the opportunity to identify barriers and enablers for being physically active. They need knowledge about their own exercise capacity and need to feel safe that physical activity is not harmful. This knowledge can be used by healthcare professionals to promote, support and eliminate misconceptions about physical activity. Barriers can potentially be transformed into enablers through increased knowledge about attitudes and prerequisites.

Skeletal muscle index determined by bioelectrical impedance analysis is a determinant of exercise capacity and a prognostic predictor in patients with congenital heart disease

BACKGROUND

Patients with congenital heart disease (CHD) reportedly have reduced exercise capacity. Underlying cardiac anatomy and a sedentary lifestyle are thought to be associated with exercise impairment. However, little has been reported regarding the relationship between quantitative body composition and exercise capacity. Bioelectrical impedance analysis (BIA) is a rapid and safe assessment method that has been widely used in clinical research. We hypothesized that bioelectrical impedance parameters are determinants of exercise capacity, and the skeletal muscle index (SMI) determined by BIA is a prognostic predictor in patients with CHD.

METHODS

We conducted a retrospective single-center study of 305 consecutive patients with CHD [median age, 26 years (range 12-60]; 48% males] admitted between 2014 and 2017. The BIA parameters were reviewed, including the edema index (EI, extracellular water to total body water ratio), SMI (skeletal muscle mass/height²), mineral index (MI, mineral mass/height²), percent body fat (%BF), and exercise capacity [peak oxygen uptake (peakVO₂)] via a cardiopulmonary exercise test.

RESULTS

The multivariate analysis revealed a significant correlation between peakVO₂ and EI (r=0.55) and peakVO₂ and SMI (r=0.49). The receiver operating characteristic curve analysis showed that the EI cut-off for peakVO₂<20ml/kg/min was 0.386 [area under the curve (AUC), 0.77; sensitivity, 0.67; specificity 0.76], and the SMI cut-off was 7.6kg/m² (AUC, 0.78; sensitivity, 0.76; specificity 0.75). Compared with patients who had biventricular morphology, patients with single ventricular morphology had a higher EI (mean, 0.381 vs. 0.387, respectively) and lower SMI (8.5 vs. 7.7, respectively), resulting in a lower peakVO₂ (27.1 vs. 20.8, respectively). The Kaplan-Meier analysis showed that a low SMI was associated with an increased risk of future heart failure-related admissions.

CONCLUSIONS

SMI determined by BIA is a determinant of exercise capacity and can be used as a prognostic predictor in patients with CHD.

Exercise capacity, physical activity, and health-related quality of life in adults with CHD

OBJECTIVES

The aim of this study was to assess exercise capacity, physical activity, and health-related quality of life within a broad and unselected group of adults with CHD.

DESIGN

From April 2009 to February 2014, 1310 patients were assessed for suitability to participate in this single-centre cross-sectional study. Seven hundred and forty-seven (57%) patients were included, performed a submaximal bicycle test, and answered questionnaires regarding physical activity and health-related quality of life. Exercise capacity, physical activity, and health-related quality of life were compared with reference values and correlations were studied.

RESULTS

The exercise capacities of men and women with CHD were 58.7 and 66.3%, respectively, of reference values. Approximately, 20-25% of the patients did not achieve the recommended amount of physical activity. In addition, men scored significantly less points on 7 out of 10 scales of health-related quality of life and women in 6 out of 10 scales, compared with reference values. The strongest correlation was between exercise capacity and the Short Form-36 (physical function).

CONCLUSIONS

Exercise capacity was impaired in all adults with CHD, including those with less complicated CHD. One-quarter of the patients did not achieve the recommended levels of physical activity. Exercise tests followed by individualised exercise prescriptions may be offered to all patients with CHD aiming to increase exercise capacity, levels of physical activity, improve health-related quality of life, and reduce the risk of acquired life-style diseases.

The value of hand grip strength (HGS) as a diagnostic and prognostic biomarker in congenital heart disease

Background

In patients with congenital heart disease (CHD), there is little data on the diagnostic and prognostic relevance of hand grip strength (HGS) for clinical assignment, while in the general population the loss of muscle strength and mass is an important risk factor in cardiovascular disease which is conversely associated with morbidity and all-cause mortality. This study aimed to assess the degree of muscle dysfunction using HGS as a biomarker in a large group of patients with CHD who often develop muscle dysfunction.

Methods

In total, 385 patients (27.6±13.1 years, 43% female) were included and assigned to 5 diagnostic groups: complex anomalies (n=131), left heart anomalies/aortopathies (n=107), right heart/pulmonary artery anomalies (n=92), primary left to-right-shunts (n=42) and miscellaneous CHD (n=13). Patients with Fontan circulation, chronic cyanosis, morphologic right systemic ventricle, arterial switch operation, or Ebstein's anomaly were analyzed separately. A control group (CG) consisted of 124 healthy individuals (30.1±12.1 years, 42% female). HGS was measured with a Jamar Hydraulic Hand Dynamometer.

Results

HGS was reduced in CHD patients compared to controls (35.2±14.6 versus 43.7±14.4 kg). Most impairments were present in females (26.1±7.6 kg). Patients with cyanosis had lower HGS values compared to acyanotic CHD patients (P=0.03). Patients with left heart lesions had the highest HSG values (40.7±14.7 kg), while patients with primary left-to-right shunt lesions had the lowest HSG values (30.9±11.3 kg). Within specific groups of cardiac anomalies, patients with Fontan circulation showed the lowest (P=0.033) and patients with a morphologic right system ventricle showed higher results (P=0.004). The late mid-term survival was favorable, and 7 patients (1.8%) died in a median interval of 422 days (range, 206-1,824 days) after HGS-testing.

Conclusions

This study provides the most comprehensive data on the use of HGS in CHD to date. Grip strength is an easily applicable, repeatedly usable and a cost-effective diagnostic tool to gain a quick, quantifiable assessment of the patient's current muscle function as an expression of cardiac fitness. Considering the low number of patients who died in the observation period, HGS may not be a suitable tool for survival assessment or identification of patients at risk. However, HGS is well suited to determine muscle function and strength and thereby to identify and to follow-up patients who have an increased cardiovascular risk.

Functional outcomes in children with anatomically repaired transposition of the great arteries with regard to congenital ventricular septal defect and coronary pattern

OBJECTIVE

Despite decreasing mortality, functional impairments in children with transposition of the great arteries (TGA) are still a concern. This study analyses health-related physical fitness (HRPF), arterial stiffness and health-related quality of life (HRQoL) in children with anatomically repaired TGA regarding congenital ventricular septal defect (VSD) and coronary patterns.

PATIENTS AND METHODS

68 children with anatomically repaired TGA with or without VSD (12.9±3.7 years, 19.1% female) were investigated between August 2014 and October 2017. HRPF was assessed by five tests of the FITNESSGRAM, arterial stiffness was measured by oscillometric measurement using Mobil-O-Graph and HRQoL was analysed with a self-report questionnaire (KINDL-R). All test results were compared with a healthy reference cohort (n=2116, 49.1% female) adjusted for sex and age.

RESULTS

Children with anatomically repaired TGA had significantly worse HRPF (z-score: -0.58±0.81, p<0.001), increased pulse wave velocity (TGA: 4.9±0.3 m/s vs healthy: 4.8±0.3 m/s, p=0.028) and central systolic blood pressure (TGA: 105.9±5.8 mm Hg vs healthy: 103.3±5.7 mm Hg, p=0.001). No difference was found for HRQoL between the two groups (total HRQoL score: TGA: 76.5±10.2 vs healthy: 75.2±10.1, p=0.315). Neither the coronary pattern nor a congenital VSD resulted in significant differences in all functional outcomes.

CONCLUSION

Children with anatomically repaired TGA exhibit impaired HRPF and increased arterial stiffness whereas their HRQoL is normal. The underlying coronary pattern seems to have no influence on the functional outcome, nor does an accompanied congenital VSD.

Validity and reliability of the Iranian version of the Cardiac Exercise Self-Efficacy Scale

BACKGROUND

The assessment of exercise self-efficacy in patients with cardiovascular disease (CVD) is necessary to conduct tailored interventions. The aim of the current study was to validate the Iranian version of the Cardiac Exercise Self-efficacy Scale (CESE) for patients with CVD.

METHODS

To develop the Iranian version of the CESE scale, a forward and back translation procedure was followed. Data were collected from 260 patients with CVD who were admitted to Imam Ali Cardiovascular Hospital, Iran, using convenience sampling. Psychometric properties of the scale including validity (face and content validity, discriminant, concurrent, convergent, divergent, and construct validity) and reliability (internal consistency, and test-retest reliability) were assessed. SPSS software was used for statistical analysis.

RESULTS

The questionnaire had a good face and content validity and reliability, with Cronbach's alpha of 0.87 and intraclass correlation coefficient (ICC) of 0.42. The questionnaire discriminated well between subgroups according to their medical conditions and the “health transition” item in the Short-Form Health Survey (SF-36). There was a significant correlation between CESE and the physical components of the SF-36 (P < 0.001). In addition, a strong to moderate significant correlation was found between the CESE and the Exercise Self-efficacy Scale (ESES) (r = 0.77; P < 0.01) and between CESE and the Hospital Anxiety and Depression Scale (HADS) total (r = -0.45; P < 0.001). The exploratory factor analysis (EFA) identified a four-factor structure model, explaining 71.02% of the observed variance.

CONCLUSION

The Persian version of the CESE is a valid and reliable instrument for the evaluation of CVD patients’ exercise self-efficacy level in performing regular exercise behaviors.

Creatinine versus cystatin C to estimate glomerular filtration rate in adults with congenital heart disease: Results of the Boston Adult Congenital Heart Disease Biobank

BACKGROUND

Glomerular filtration rate is a key physiologic variable with a central role in clinical decision making and a strong association with prognosis in diverse populations. Reduced estimated glomerular filtration rate (eGFR) is common among adults with congenital heart disease (ACHD).

METHODS

We conducted a prospective cohort study of outpatient ACHD ≥18 years old seen in 2012-2017. Creatinine and cystatin C were measured; eGFR was calculated using either the creatinine or cystatin C Chronic Kidney Disease-Epidemiology Collaboration equation (CKD-EPI_Cr and CKD-EPI_CysC, respectively). Survival analysis was performed to define the relationship between eGFR and both all-cause mortality and a composite outcome of death or nonelective cardiovascular hospitalization.

RESULTS

Our cohort included 911 ACHD (39 ± 14 years old, 49% female). Mean CKD-EPI_Cr and CKD-EPI_CysC were similar (101 ± 20 vs 100 ± 23 mL/min/1.73 m²), but CKD-EPI_Cr estimates were higher for patients with a Fontan circulation (n = 131, +10 ± 19 mL/min/1.73 m²). After mean follow-up of 659 days, 128 patients (14.1%) experienced the composite outcome and 31 (3.4%) died. CKD-EPI_CysC more strongly predicted all-cause mortality (eGFR <60 vs >90 mL/min/1.73 m²: CKD-EPI_CysC unadjusted HR = 20.2 [95% CI 7.6-53.1], C-statistic = 0.797; CKD-EPI_Cr unadjusted HR = 4.6 [1.7-12.7], C-statistic = 0.620). CKD-EPI_CysC independently predicted the composite outcome, whereas CKD-EPI_Cr did not (CKD-EPI_CysC adjusted HR = 3.0 [1.7-5.3]; CKD-EPI_Cr adjusted HR = 1.5 [0.8-3.1]). Patients reclassified to a lower eGFR category by CKD-EPI_CysC, compared with CKD-EPI_Cr, were at increased risk for the composite outcome (HR = 2.9 [2.0-4.3], P < .0001); those reclassified to a higher eGFR class were at lower risk (HR = 0.5 [0.3-0.9], P = .03).

CONCLUSIONS

Cystatin C-based eGFR more strongly predicts clinical events than creatinine-based eGFR in ACHD. Creatinine-based methods appear particularly questionable in the Fontan circulation.

Risk of Cancer Among Children and Young Adults With Congenital Heart Disease Compared With Healthy Controls

IMPORTANCE

Adult patients with congenital heart disease (CHD) have an increased incidence of cancer, presumably owing to repeated radiation exposure, genetic predisposition, or repeated stress factors during heart interventions. However, there are limited data on the risk of cancer in children and young adults with CHD compared with the general population.

OBJECTIVE

To determine the risk of developing cancer from birth to age 41 years among patients with CHD compared with healthy matched controls.

DESIGN, SETTING, AND PARTICIPANTS

This registry-based, matched, prospective cohort study in Sweden used data from the Patient and Cause of Death Registers. Successive cohorts of patients with CHD born from 1970 to 1979, 1980 to 1989, and 1990 to 1993 were identified. Each patient (n = 21 982) was matched for birth year, sex, and county with 10 controls without CHD from the general population (n = 219 816). Follow-up and comorbidity data were collected from 1970 until 2011. Data analysis began in September 2018 and concluded in February 2019.

MAIN OUTCOMES AND MEASURES

Risk of cancer among children and young adults with CHD and among healthy controls.

RESULTS

Among 21 982 individuals with CHD and 219 816 healthy matched controls, 428 patients with CHD (2.0%) and 2072 controls (0.9%) developed cancer. Among patients with CHD, the mean (SD) age at follow-up was 26.6 (8.4) years, and 11 332 participants (51.6%) were men. Among healthy controls, the mean (SD) age at follow-up was 28.5 (9.1) years, and 113 319 participants (51.6%) were men. By the age of 41 years, 1 of 50 patients with CHD developed cancer. The overall hazard ratio (HR) for cancer was 2.24 (95% CI, 2.01-2.48) in children and young adults with CHD compared with controls. Risk increased by each successive birth cohort to an HR of 3.37 (95% CI, 2.60-4.35) among those born from 1990 to 1993. The risk of cancer was similar in men and women with CHD (men: HR, 2.41; 95% CI, 2.08-2.79; women: HR, 2.08; 95% CI, 1.80-2.41). The HR for cancer among patients with CHD who underwent surgery was 1.95 (95% CI, 1.58-2.33) compared with controls; for patients with CHD who had not undergone surgery, the HR was 2.43 (95% CI, 2.12-2.76). According to a hierarchical classification, a significantly increased risk of cancer was found among patients with complex heart lesions, such as conotruncal defects (HR, 2.29; 95% CI, 1.62-3.25), compared with healthy controls.

CONCLUSIONS AND RELEVANCE

Children and young adult patients with CHD had an increased risk of developing cancer compared with healthy matched controls, and the risk was significantly higher among patients with CHD from the most recent birth cohort. An increased risk of cancer in all CHD lesion groups was found, and a systematic screening for cancer could be considered for this at-risk group of patients.

Transcatheter closure of atrial septal defect in adults: time-course of atrial and ventricular remodeling and effects on exercise capacity

Investigate ventricular and atrial remodeling following atrial septal defect (ASD) closure and examine if pulmonary-to-systemic flow ratio (QP/QS) and right ventricular (RV) volume predict improvement, determined as percentage of predicted oxygen uptake (VO₂%). Long-term cardiovascular magnetic resonance (CMR) data on atrial and ventricular remodeling after ASD-closure is limited and treatment effect on exercise capacity is debated. Sixteen patients undergoing transcatheter ASD closure and 16 age and sexmatched controls were studied. CMR was performed before treatment, the day after and 3 and 12 months later. Exercise test with gas analysis was performed before and 12 months after treatment. QP/QS decreased from 2.1 ± 0.5 to 1.4 ± 0.3 at day 1 and 1.1 ± 0.1 at 3 and 12 months. Left ventricular (LV) volumes increased and normalized on day 1 whereas left atrial volumes were unchanged. RV and right atrial volumes decreased the first 3 months. LV and RV volumes had not equalized at 12 months (RV/LV ratio 1.2 ± 0.1, P < 0.01) and RV ejection fraction remained decreased compared to controls. Improvement of VO₂% after ASD closure (P < 0.01) was inversely related to QP/QS at rest (r = - 0.56, P < 0.05) but unrelated to RV end-diastolic volume (P = 0.16). Following transcatheter ASD closure, LV adaptation is rapid and RV adaptation is prolonged, with decreased systolic RV function. Patients with smaller shunts had larger improvement in VO₂% suggesting patients with defects of borderline hemodynamic significance might benefit from closure. This may be due to impaired LV diastolic function influencing shunt size and exercise capacity following ASD closure.

Geographical variation and predictors of physical activity level in adults with congenital heart disease

Background

Physical activity is important to maintain and promote health. This is of particular interest in patients with congenital heart disease (CHD) where acquired heart disease should be prevented. The World Health Organization (WHO) recommends a minimum of 2.5 h/week of physical activity exceeding 3 metabolic equivalents (METS) to achieve positive health effects. It is unknown whether physical activity levels (PAL) in adult CHD patients differ by country of origin.

Methods

3896 adults with CHD recruited from 15 countries over 5 continents completed self-reported instruments, including the Health Behaviour Scale (HBS-CHD), within the APPROACH-IS project. For each patient, we calculated whether WHO recommendations were achieved or not. Associated factors were investigated using Generalized Linear Mixed Models.

Results

On average, 31% reached the WHO recommendations but with a great variation between geographical areas (India: 10%–Norway: 53%). Predictors for physical activity level in line with the WHO recommendations, with country of residence as random effect, were male sex (OR 1.78, 95%CI 1.52–2.08), NYHA-class I (OR 3.10, 95%CI 1.71–5.62) and less complex disease (OR 1.46, 95%CI 1.16–1.83). In contrast, older age (OR 0.97, 95%CI 0.96–0.98), lower educational level (OR 0.41, 95%CI 0.26–0.64) and being unemployed (OR 0.57, 95%CI 0.42–0.77) were negatively associated with reaching WHO recommendations.

Conclusions

A significant proportion of patients with CHD did not reach the WHO physical activity recommendations. There was a large variation in physical activity level by country of origin. Based on identified predictors, vulnerable patients may be identified and offered specific behavioral interventions.

[Cardiac rehabilitation in adults with congenital heart diseases]

The great advances in the medical and surgical management of congenital heart diseases have allowed many children to reach adulthood with often a good hemodynamic result. Nevertheless most of these adults have a limitation of their functional capacity. This limitation is more or less important, penalizes them in their daily life and alters their quality of life. The origin of this limitation is generally multifactorial. It is linked, of course, to the severity of the heart disease and the quality of the operative result. But there is very often a physical deconditioning. It can be secondary to the heart disease but is often secondary to a lack of physical activity. It is the parents, sometimes overprotective, but frequently the doctors who imposed, often wrongly, this restriction. It is essential to take this dimension into account in view of the important benefits expected for health and quality of life. Cardiac rehabilitation is a privileged tool for providing advice in a suitable environment. This requires close collaboration between cardiac rehabilitators and congenital cardiologists to offer appropriate care. We bring here some reflections and the basic elements to guide the re-training of these patients.

Exercise self-efficacy in adults with congenital heart disease

Background

Physical activity improves health, exercise tolerance and quality of life in adults with congenital heart disease (CHD), and exercise training is in most patients a high-benefit low risk intervention. However, factors that influence the confidence to perform exercise training, i.e. exercise self-efficacy (ESE), in CHD patients are virtually unknown. We aimed to identify factors related to low ESE in adults with CHD, and potential strategies for being physically active.

Methods

Seventy-nine adults with CHD; 38 with simple lesions (16 women) and 41 with complex lesions (17 women) with mean age 36.7 ± 14.6 years and 42 matched controls were recruited. All participants completed questionnaires on ESE and quality of life, carried an activity monitor (Actiheart) during four consecutive days and performed muscle endurance tests.

Results

ESE in patients was categorised into low, based on the lowest quartile within controls, (≤ 29 points, n = 34) and high (> 29 points, n = 45). Patients with low ESE were older (42.9 ± 15.1 vs. 32.0 ± 12.4 years, p = 0.001), had more complex lesions (65% vs. 42%, p = 0.05) more often had New York Heart Association functional class III (24% vs. 4%, p = 0.01) and performed fewer shoulder flexions (32.5 ± 15.5 vs. 47.7 ± 25.0, p = 0.001) compared with those with high ESE. In a logistic multivariate model age (OR; 1.06, 95% CI 1.02–1.10), and number of shoulder flexions (OR; 0.96, 95% CI 0.93–0.99) were associated with ESE.

Conclusion

In this study we show that many adults with CHD have low ESE. Age is an important predictor of low ESE and should, therefore, be considered in counselling patients with CHD. In addition, muscle endurance training may improve ESE, and thus enhance the potential for being physically active in this population.

Web-Based Motor Intervention to Increase Health-Related Physical Fitness in Children With Congenital Heart Disease: A Study Protocol

Objective: Exercise interventions are underutilized in children with congenital heart disease (CHD) especially when the primary outcome is not peak oxygen uptake. Most of the studies are restricted to a low sample size and proximity of the patients to the study centers. Now eHealth approaches bear a promising but also challenging opportunity to transmit such intervention programs to participants, and check progress and compliance from remote. This study will aim to improve health-related physical fitness (HRPF) with a 24 weeks web-based exercise intervention. Methods and Design: The current study is planned as a randomized control trial (RCT) with a crossover design and the aim to improve functional outcome measures. It also estimates adherence and feasibility in patients with CHD in this web-based exercise/motor intervention over 24 weeks. Primary outcome will be the improvement of HRPF. Secondary outcomes are, functional and structural arterial stiffness measures and health-related quality of life. Thus, 70 children from 10 to 18 years with CHD of moderate and complex severity will be recruited and allocated randomly 1:1 in two study arms after baseline testing for their HRPF, arterial stiffness measures and health-related quality of life. For 24 weeks, participants in the intervention arm will receive three weekly exercise video clips of 20 min each. Every video clip comprises 20 child-oriented exercises which have to be executed for 30 s followed by a recovery period of 30 s. Each session will start with 3-4 warming-up exercises, followed by 10-12 strength and flexibility exercises, and ending with 3-4 min of cool down or stretching tasks. Continuous video clips will be streamed from a web-based e-Learning platform. The participant simply has to imitate the execution and follow some short advices. After each session, a brief online survey will be conducted to assess perceived exertion and feasibility. Discussion: The study will help to determine the efficacy and applicability of a web-based exercise intervention in children with CHD in regard to functional outcome measures. In addition, it will outline the effectiveness of remote monitoring, which provides a cost effective approach to reach patients with CHD that are low in prevalence and often do not live in close proximity to their tertiary center. Trial Registration: https://ClinicalTrials.gov Identifier: NCT03488797.

Updated reliability and normative values for the standing heel-rise test in healthy adults

OBJECTIVES

The heel-rise test is used to assess the strength and endurance of the plantar flexors in everyday clinical practice. However, several factors may affect outcomes, including sex, age, body mass index and activity level. The aims of this study were to revisit the reliability and normative values of this test, and establish normative equations accounting for several factors.

DESIGN

Cross-sectional observational study with test-retest.

SETTING

Community.

PARTICIPANTS

Volunteers (n=566, age 20 to 81 years).

INTERVENTIONS

Subjects performed single-legged heel rises to fatigue, standing on a 10° incline, once on each leg. A subset of subjects (n=32) repeated the test 1 week later. Reliability was quantified using intraclass (ICC) correlation coefficients and Bland-Altman plots {mean difference [95% limits of agreement (LOA)]}, whereas the impact of sex, age, body mass index and activity level on the number of heel rises was determined using non-parametric regression models.

RESULTS

The test showed excellent reliability (ICC=1.0 right leg, 1.0 left leg), with mean between-day differences in the total number of heel-rise repetitions of 0.2 (95% LOA -6.2 to 6.5) and 0.1 (95% LOA -6.1 to 6.2) for right and left legs, respectively. Overall, males completed more repetitions than females (median 24 vs 21). However, older females (age >60years) outperformed older males. According to the model, younger males with higher activity levels can complete the most heel rises.

CONCLUSIONS

The heel-rise test is highly reliable. The regression models herein can be employed by clinicians to evaluate the outcomes of heel-rise tests of individuals against a comparable normative population.

A Novel TBX1 Loss-of-Function Mutation Associated with Congenital Heart Disease

Congenital heart disease (CHD) is the most prevalent type of birth defect in humans and is the leading non-infectious cause of infant death worldwide. There is a growing body of evidence demonstrating that genetic defects play an important role in the pathogenesis of CHD. However, CHD is a genetically heterogeneous disease and the genetic basis underpinning CHD in an overwhelming majority of patients remains unclear. In this study, the coding exons and splice junction sites of the TBX1 gene, which encodes a T-box homeodomain transcription factor essential for proper cardiovascular morphogenesis, were sequenced in 230 unrelated children with CHD. The available family members of the index patient carrying an identified mutation and 200 unrelated ethnically matched healthy individuals used as controls were subsequently genotyped for TBX1. The functional effect of the TBX1 mutation was predicted by online program MutationTaster and characterized by using a dual-luciferase reporter assay system. As a result, a novel heterozygous TBX1 mutation, p.Q277X, was identified in an index patient with double outlet right ventricle (DORV) and ventricular septal defect (VSD). Genetic analysis of the proband's available relatives showed that the mutation co-segregated with CHD transmitted in an autosomal dominant pattern with complete penetrance. The nonsense mutation, which was absent in 400 control chromosomes, altered the amino acid that was completely conserved evolutionarily across species and was predicted to be disease-causing by MutationTaster. Biochemical analysis revealed that Q277X-mutant TBX1 lost transcriptional activating function when compared with its wild-type counterpart. This study firstly associates TBX1 loss-of-function mutation with enhanced susceptibility to DORV and VSD in humans, which provides novel insight into the molecular mechanism underlying CHD and suggests potential implications for the development of new preventive and therapeutic strategies for CHD.

PITX2 Loss-of-Function Mutation Contributes to Congenital Endocardial Cushion Defect and Axenfeld-Rieger Syndrome

Congenital heart disease (CHD), the most common type of birth defect, is still the leading non-infectious cause of infant morbidity and mortality in humans. Aggregating evidence demonstrates that genetic defects are involved in the pathogenesis of CHD. However, CHD is genetically heterogeneous and the genetic components underpinning CHD in an overwhelming majority of patients remain unclear. In the present study, the coding exons and flanking introns of the PITX2 gene, which encodes a paired-like homeodomain transcription factor 2essential for cardiovascular morphogenesis as well as maxillary facial development, was sequenced in 196 unrelated patients with CHD and subsequently in the mutation carrier's family members available. As a result, a novel heterozygous PITX2 mutation, p.Q102X for PITX2a, or p.Q148X for PITX2b, or p.Q155X for PITX2c, was identified in a family with endocardial cushion defect (ECD) and Axenfeld-Rieger syndrome (ARS). Genetic analysis of the pedigree showed that the nonsense mutation co-segregated with ECD and ARS transmitted in an autosomal dominant pattern with complete penetrance. The mutation was absent in 800 control chromosomes from an ethnically matched population. Functional analysis by using a dual-luciferase reporter assay system revealed that the mutant PITX2 had no transcriptional activity and that the mutation eliminated synergistic transcriptional activation between PITX2 and NKX2.5, another transcription factor pivotal for cardiogenesis. To our knowledge, this is the first report on the association of PITX2 loss-of-function mutation with increased susceptibility to ECD and ARS. The findings provide novel insight into the molecular mechanisms underpinning ECD and ARS, suggesting the potential implications for the antenatal prophylaxis and personalized treatment of CHD and ARS.

A novel NKX2.6 mutation associated with congenital ventricular septal defect

Congenital heart disease (CHD) is the most common birth defect and is the most prevalent non-infectious cause of infant death. Aggregating evidence demonstrates that genetic defects are involved in the pathogenesis of CHD. However, CHD is genetically heterogeneous and the genetic determinants for CHD in an overwhelming majority of patients remain unknown. In this study, the coding regions and splice junctions of the NKX2.6 gene, which encodes a homeodomain transcription factor crucial for cardiovascular development, were sequenced in 210 unrelated CHD patients. As a result, a novel heterozygous NKX2.6 mutation, p.K152Q, was identified in an index patient with ventricular septal defect (VSD). Genetic analysis of the proband's available family members showed that the mutation cosegregated with VSD transmitted as an autosomal dominant trait with complete penetrance. The missense mutation was absent in 400 control chromosomes and the altered amino acid was completely conserved evolutionarily across species. Due to unknown transcriptional targets of NKX2.6, the functional characteristics of the identified mutation at transcriptional activity were analyzed by using NKX2.5 as a surrogate. Alignment between human NKX2.6 and NKX2.5 proteins displayed that K152Q-mutant NKX2.6 was equivalent to K158Q-mutant NKX2.5, and introduction of K158Q into NKX2.5 significantly reduced its transcriptional activating function when compared with its wild-type counterpart. This study firstly links NKX2.6 loss-of-function mutation with increased susceptibility to isolated VSD, providing novel insight into the molecular mechanism underpinning VSD and contributing to the development of new preventive and therapeutic strategies for this common form of CHD.

Prevalence and spectrum of Nkx2.6 mutations in patients with congenital heart disease

Congenital heart disease (CHD) is the most common form of birth defect and is the most prevalent non-infectious cause of infant death. A growing body of evidence documents that genetic defects are involved in the pathogenesis of CHD. However, CHD is a genetically heterogeneous disease and the genetic basis underpinning CHD in an overwhelming majority of patients remain unclear. In this study, the coding exons and flanking introns of the Nkx2.6 gene, which codes for a homeodomain-containing transcription factor important for normal cardiovascular development, were sequenced in 320 unrelated patients with CHD, and two novel heterozygous Nkx2.6 mutations, p.V176M and p.K177X, were identified in two unrelated patients with CHD, respectively, including a patient with tetralogy of Fallot and a patient with double outlet of right ventricle and ventricular septal defect. The mutations were absent in 400 control chromosomes and the altered amino acids were completely conserved evolutionarily across species. Due to unknown transcriptional targets of Nkx2.6, the functional consequences of the identified mutations at transcriptional activity were evaluated by using Nkx2.5 as a surrogate. Alignment between human Nkx2.6 and Nkx2.5 proteins showed that V176M-mutant Nkx2.6 was equivalent to V182M-mutant Nkx2.5 and K177X-mutant Nkx2.6 was equal to K183X-mutant Nkx2.5, and introduction of V182M or K183X into Nkx2.5 significantly diminished its transcriptional activating function when compared with its wild-type counterpart. To our knowledge, this is the first report on the association of Nkx2.6 loss-of-function mutation with increased susceptibility to tetralogy of Fallot or double outlet of right ventricle and ventricular septal defect, providing novel insight into the molecular mechanism of CHD.

Novel PITX2c loss-of-function mutations associated with complex congenital heart disease

Congenital heart disease (CHD) is the most common form of birth defect in humans and is the leading non-infectious cause of infant mortality. Emerging evidence strongly suggests that genetic risk factors play an important role in the pathogenesis of CHD. However, CHD is of pronounced genetic heterogeneity, and the genetic defects responsible for CHD in an overwhelming majority of patients remain unclear. In this study, the entire coding region and splice junction sites of the PITX2c gene, which encodes a paired-like homeodomain transcription factor crucial for proper cardiovascular morphogenesis, was sequenced in 170 unrelated neonates with CHD. The available relatives of the mutation carriers and 200 unrelated ethnically matched healthy individuals were genotyped. The disease-causing potential of the PITX2c sequence variations was predicted by MutationTaster and PolyPhen-2. The functional effect of the mutations was characterized using a luciferase reporter assay system. As a result, 2 novel heterozygous PITX2c mutations, p.R91Q and p.T129S, were identified in 2 unrelated newborns with transposition of the great arteries and ventricular septal defect, respectively. A genetic scan of the pedigrees revealed that each mutation co-segregated with CHD transmitted in an autosomal dominant pattern with complete penetrance. The mutations, which altered the amino acids completely conserved evolutionarily, were absent in 400 normal chromosomes and were predicted to be causative. Functional analysis revealed that the PITX2c mutations were both associated with significantly diminished transcriptional activity compared with their wild-type counterpart. This study demonstrates the association between PITX2c loss-of-function mutations and the transposition of the great arteries and ventricular septal defect in humans, providing further insight into the molecular mechanisms responsible for CHD.