Functional Capacity in Congenital Heart Disease: A Systematic Review and Meta-Analysis

Normative values for heart rate response to exercise in young athletes at 10-18 years old

The assessment of the chronotropic response during acute physical exertion can allow the discovery of many cardiovascular diseases even at a young age. However, the increase in heart rate (HR) depends on the age and sex of the subject and the modality of the graded exercise test. This study aims to provide sex- and age-related normative values for heart rate performance in young athletes aged 10 to 18. A retrospective study was carried out on 7896 young athletes (5356 males and 2540 females) aged between 10 and 18 who underwent pre-participation screening to obtain eligibility for competitive sport. First, anthropometric parameters, performance data, and HR are reported. Thus, each age calculated third, tenth, twenty-fifth, fiftieth, seventy-fifth, ninetieth, and ninety-seventh percentiles for the stage-by-stage HR response, according to sex and graded exercise test modality category. Young female athletes of all ages showed lower performance with fewer stages performed on the cycle ergometer and the treadmill. Young male athletes on treadmill and cycle ergometers show lower HR values at submaximal intensities. The treadmill allows a longer duration than the cycle ergometer for males and females. Sex, age, and the specificity of the movement performed must be considered in assessing the chronotropic response in the young population, particularly for those who carry out a training program. In addition, providing reference values of HR response to acute physical exertion may allow for a better functional assessment of the young athletes.

Exercise Capacity in Children and Adolescents With Congenital Heart Disease: A Systematic Review and Meta-Analysis

Background

Congenital heart disease (CHD) entails structural defects in the morphogenesis of the heart or its main vessels. Analyzing exercise capacity of children and adolescents with CHD is important to improve their functional condition and quality of life, since it can allow timely intervention on poor prognostic factors associated with higher risk of morbidity and mortality.

Objective

To describe exercise capacity in children and adolescents with CHD compared with healthy controls.

Methods

A systematic review was carried out. Randomized clinical trials and observational studies were included assessing exercise capacity through direct and indirect methods in children and adolescents between 5 and 17 years-old. A sensitive analysis was performed including studies with CHD repaired participants. Additionally, it was sub-analyzed by age range (< and ≥ 12 years old). Two independent reviewers analyzed the studies, extracted the data, and assessed the quality of the evidence.

Results

5619 articles were found and 21 were considered for the review. Eighteen articles used the direct exercise capacity measurement method by cardiopulmonary exercise test (CPET). The CHD group showed significant differences in peak oxygen consumption (VO₂peak) with a value of −7.9 ml/Kg/min (95% CI: −9.9, −5.9, p = 0.00001), maximum workload (Wmax) −41.5 (95% CI: −57.9, −25.1 watts, p = 0.00001), ventilatory equivalent (VE/VCO₂) slope 2.6 (95% CI: 0.3, 4.8), oxygen pulse (O₂ pulse)−2.4 ml/beat (95% CI: −3.7, −1.1, p = 0.0003), and maximum heart rate (HRmax) −15 bpm (95% CI: −18, −12 bpm, p = 0.00001), compared with healthy controls. Adolescents (≥ 12 yrs) with CHD had a greater reduction in VO₂peak (−10.0 ml/Kg/min (95% CI: −12.0, −5.3), p < 0.00001), Wmax (−45.5 watts (95% CI: −54.4, −36.7), p < 0.00001) and HRmax (−21 bpm (95% CI: −28, −14), p<0.00001).

Conclusion

Suffering CHD in childhood and adolescence is associated with lower exercise capacity as shown by worse VO₂peak, Wmax, VE/VCO₂ slope, O₂ pulse, and HRmax compared with matched healthy controls. The reduction in exercise capacity was greater in adolescents.

Systematic Review Registration

www.crd.york.ac.uk/prospero/display_record.php?RecordID=208963, identifier: CRD42020208963.

Reduced Forced Vital Capacity and the Number of Chest Wall Surgeries are Associated with Decreased Exercise Capacity in Children with Congenital Heart Disease

Low forced vital capacity (FVC) is associated with decreased exercise capacity in CHD. Multiple prior cardiac surgeries have been associated with low FVC. We seek to understand the relationship between low FVC, number of cardiac surgeries and cardiopulmonary response leading to decreased exercise capacity. Retrospective chart review of demographics, surgical history and exercise testing including spirometry was performed in patients with CHD. Single ventricle patients were excluded. Low FVC was defined as a Z-score below the lower limit of normal. Exercise parameters were expressed as a percent of predicted. There were 93 patients with 2 ventricle CHD identified over 34 months with cardiopulmonary exercise testing. The FVC Z-score directly correlated with peak V̇O₂% (R² = 0.07, p < 0.05), and the O₂ pulse% (R² = 0.25, p < 0.0001). The VE/VCO₂ was inversely related to the FVC Z-score (R² = 0.11, p < 0.01). Patients with minimum three prior surgeries had decreased peak VO₂% (63.7 vs. 72.8, p < 0.05), decreased peak O₂ pulse% (80.8 vs. 97.9, p < 0.01) and a lower mean FVC Z-score (- 1.9 vs - 0.38, p < 0.01). The FVC Z-score and number of surgeries both predicted peak V̇O₂% in multivariate analysis. Our study demonstrated that low FVC and three or more prior cardiac surgeries were associated with lower exercise capacity and lower stroke volume response. More cardiac surgeries were also associated with low FVC. However, both low FVC and the number of surgeries were independent predictors of exercise capacity.

Novel Point Mutations in 3'-Untranslated Region of GATA4 Gene Are Associated with Sporadic Non-syndromic Atrial and Ventricular Septal Defects

OBJECTIVE

Transcription factor GATA4 has significant roles in embryonic heart development. Mutations of GATA4 appear to be responsible for a wide variety of congenital heart defects (CHD). Despite the high prevalence of GATA4 mutations in CHD phenotypes, extensive studies have not been performed. The 3'-untranslated region (3'-UTR) of the GATA4 gene comprises regulatory motifs and microRNA binding sites that are critical for the appropriate gene expression, nuclear transportation, and regulation of translation, and stability of mRNA. This study aimed to evaluate the association between mutations in the 3'-UTR of the GATA4 gene and CHD risk among Iranian patients.

METHODS

We analyzed the coding region of exon 6 and the whole 3'-UTR of GATA4 in DNA isolated from 175 blood samples of CHD patients and 115 unrelated healthy individuals. The functional importance of the observed GATA4 mutations was evaluated using a variety of bioinformatics algorithms for assessment of nonsynonymous mutations and those observed in miRNA binding sites of 3'-UTR.

RESULTS

Twenty-one point mutations including one missense mutation (c.511A>G: p.Ser377Gly) in exon 6 and 20 nucleotide variations in 3'-UTR of GATA4 gene were identified in 65 of the 175 CHD patients. In our patients, we identified 12 novel sequence alterations and 8 single nucleotide polymorphisms in the 3'-UTR of GATA4. Most of them had statistically significant differences between CHD patients and controls.

CONCLUSION

Our results suggest that 3'-UTR variations of the GATA4 gene probably change microRNA binding sites and present an additional molecular risk factor for the susceptibility of CHD.

Characterization of physical literacy in children with chronic medical conditions compared with healthy controls: a cross-sectional study

To determine the physical literacy, defined as the capability for a physically active lifestyle, of children with medical conditions compared with healthy peers, this multicenter cross-sectional study recruited children with medical conditions from cardiology, neurology (including concussion), rheumatology, mental health, respirology, oncology, hematology, and rehabilitation (including cerebral palsy) clinics. Participants aged 8-12 years (N = 130; mean age: 10.0 ± 1.44 years; 44% female) were randomly matched to 3 healthy peers from a normative database, based on age, gender, and month of testing. Total physical literacy was assessed by the Canadian Assessment of Physical Literacy, a validated assessment of physical literacy measuring physical competence, daily behaviour, knowledge/understanding, and motivation/confidence. Total physical literacy mean scores (/100) did not differ (t(498) = -0.67; p = 0.44) between participants (61.0 ± 14.2) and matched healthy peers (62.0 ± 10.7). Children with medical conditions had lower mean physical competence scores (/30; -6.5 [-7.44 to -5.51]; p < 0.001) but higher mean motivation/confidence scores (/30; 2.6 [1.67 to 3.63]; p < 0.001). Mean daily behaviour and knowledge/understanding scores did not differ from matches (/30; 1.8 [0.26 to 3.33]; p = 0.02;/10; -0.04 [-0.38 to 0.30]; p = 0.81; respectively). Children with medical conditions are motivated to be physically active but demonstrate impaired movement skills and fitness, suggesting the need for targeted interventions to improve their physical competence. Novelty: Physical literacy in children with diverse chronic medical conditions is similar to healthy peers. Children with medical conditions have lower physical competence than healthy peers, but higher motivation and confidence. Physical competence (motor skill, fitness) interventions, rather than motivation or education, are needed for these youth.

Caregiving Strategies in Families of Children with Congenital Heart Disease: A Qualitative Study

Background

The families of children with Congenital Heart Disease (CHD) experience challenges in taking care of their child, which may affect the whole family. Therefore, the families need to manage and organize the caregiving process for the child. In order to help families provide optimized and quality care for their child, it is important to understand how they manage caregiving challenges. This study was conducted with the aim to explore the strategies used by families for managing family caregiving for their child.

Materials and Methods

This qualitative study was conducted on families of children with CHD referred to hospitals in Mashhad, Iran. The participants were selected using a purposive sampling method. The data were collected from among 40 eligible participants using in-depth and semi-structured interviews from November 2017 to December 2018. Conventional content analysis was used for data analysis and MAXQDA software for managing the coding process.

Results

According to the results, effort to manage caregiving emerged as the main theme, which included the 4 categories of "monitoring the child's health conditions," "organizing family life," "optimizing family life," and "establishing interaction."

Conclusions

The families used various strategies to manage caregiving including monitoring of the child's health conditions, organization, and optimization of family life, and effective interaction based on their knowledge, experiences, beliefs, and available sources. The results of the present study can help healthcare professionals and nurses to develop family-centered empowerment programs in order to promote families' abilities to manage family caregiving for a child with CHD.

Three-dimensional alignment of microvasculature and cardiomyocytes in the developing ventricle

While major coronary artery development and pathologies affecting them have been extensively studied, understanding the development and organization of the coronary microvasculature beyond the earliest developmental stages requires new tools. Without techniques to image the coronary microvasculature over the whole heart, it is likely we are underestimating the microvasculature’s impact on normal development and diseases. We present a new imaging and analysis toolset to visualize the coronary microvasculature in intact embryonic hearts and quantify vessel organization. The fluorescent dyes DiI and DAPI were used to stain the coronary vasculature and cardiomyocyte nuclei in quail embryo hearts during rapid growth and morphogenesis of the left ventricular wall. Vessel and cardiomyocytes orientation were automatically extracted and quantified, and vessel density was calculated. The coronary microvasculature was found to follow the known helical organization of cardiomyocytes in the ventricular wall. Vessel density in the left ventricle did not change during and after compaction. This quantitative and automated approach will enable future cohort studies to understand the microvasculature’s role in diseases such as hypertrophic cardiomyopathy where misalignment of cardiomyocytes has been observed in utero.