Congenital Heart Disease Heart Research Articles

Single-Cell Reconstruction and Mutation Enrichment Analysis Identifies Dysregulated Cardiomyocyte and Endothelial Cells in Congenital Heart Disease.

Congenital heart disease (CHD) is one of the most prevalent neonatal congenital anomalies. To catalog the putative candidate CHD risk, we collected 16,349 variants (single nucleotide variants (SNVs) and Indels) impacting 8,308 genes in 3,166 CHD cases for a comprehensive meta-analysis. Using ACMG guidelines we excluded the 0.1% of benign/likely benign variants and resulting data set consisted of 83% predicted loss of function variants and 17% missense variants. Seventeen percent were de novo variants. A stepwise analysis identified 90 variant-enriched CHD genes, of which six (GPATCH1, NYNRIN, TCLD2, CEP95, MAP3K19 and TTC36) were novel candidate CHD genes. Single cell transcriptome cluster reconstruction analysis on six CHD tissues and four controls revealed upregulation of top 10 frequently mutated genes primarily in cardiomyocytes. NOTCH1 (highest number of variants) and MYH6 (highest number of recurrent variants) expression was elevated in endocardial cells and cardiomyocytes, respectively, and 60% of these gene variants were associated with tetralogy of Fallot and coarctation of the aorta, respectively. Pseudobulk analysis using single cell transcriptome, revealed significant (p<0.05) upregulation of both NOTCH1 (endocardial cells) and MYH6 (cardiomyocytes) in the control heart data. We observed nine different subpopulations of CHD heart cardiomyocytes of which only four were observed in the control heart. This is the first comprehensive meta-analysis combining genomics and CHD single cell transcriptomics, identifying the most frequently mutated CHD genes, and demonstrating CHD gene heterogeneity, suggesting that multiple genes contribute to the phenotypic heterogeneity of CHD. Cardiomyocytes and endocardial cells are identified as major CHD-related cell types.

ARTIFICIAL INTELLIGENCE-BASED FETAL CONGENITAL HEART DISEASE DIAGNOSTICS: A SURVEY OF STATE-OF-THE-ART TECHNIQUES

With the development of computer technology and neural networks, artificial intelligence (AI) has become sufficiently mature to assist in various technical and medical tasks, including the prenatal diagnosis of congenital heart disease (CHD). Moreover, the AI-based approach to solving this challenge has provided new ideas, concepts, and techniques. This review focuses on fetal CHD and conventional methods of its diagnostics, highlights the main achievements and particular techniques of AI application to CHD diagnostics, and discusses their advantages, drawbacks, and ways of further improvement regarding CHD and other heart disease.

Development of the data registry for the Cardiac Neurodevelopmental Outcome Collaborative.

Children with congenital heart disease (CHD) can face neurodevelopmental, psychological, and behavioural difficulties beginning in infancy and continuing through adulthood. Despite overall improvements in medical care and a growing focus on neurodevelopmental screening and evaluation in recent years, neurodevelopmental disabilities, delays, and deficits remain a concern. The Cardiac Neurodevelopmental Outcome Collaborative was founded in 2016 with the goal of improving neurodevelopmental outcomes for individuals with CHD and pediatric heart disease. This paper describes the establishment of a centralised clinical data registry to standardize data collection across member institutions of the Cardiac Neurodevelopmental Outcome Collaborative. The goal of this registry is to foster collaboration for large, multi-centre research and quality improvement initiatives that will benefit individuals and families with CHD and improve their quality of life. We describe the components of the registry, initial research projects proposed using data from the registry, and lessons learned in the development of the registry.

Environmental changes surrounding congenital heart disease.

As the outcomes of patients with congenital heart disease (CHD) improve, the number of patients is accumulating and the proportion of adult CHD patients is gradually increasing. Accordingly, the proportion of typical adult diseases such as coronary arterial disease, diabetes, dyslipidemia, and hypertension among patients with CHD is increasing, as is the medical burden due to residual cardiac problems, heart failure, and arrhythmias. Due to increasing genetic knowledge, efforts are being made to provide active medical support through risk stratification. Surgical techniques and prostheses are also developing, the instruments used for transcatheter intervention are diversifying, and the range of therapeutic options is expanding. In addition, owing to the development of electronic devices, heart rhythm and blood pressure monitoring instruments have been miniaturized and diversified. In this process, a vast amount of information is collected; therefore, the current systematic review examined their clinical usefulness. A team approach consisting of experts from various fields is essential for the treatment of patients with CHD and advanced heart failure.

Translational potential of hiPSCs in predictive modeling of heart development and disease.

Congenital heart disease (CHD) represents a major class of birth defects worldwide and is associated with cardiac malformations that often require surgical intervention immediately after birth. Despite the intense efforts from multicentric genome/exome sequencing studies that have identified several genetic variants, the etiology of CHD remains diverse and often unknown. Genetically modified animal models with candidate gene deficiencies continue to provide novel molecular insights that are responsible for fetal cardiac development. However, the past decade has seen remarkable advances in the field of human induced pluripotent stem cell (hiPSC)-based disease modeling approaches to better understand the development of CHD and discover novel preventative therapies. The iPSCs are derived from reprogramming of differentiated somatic cells to an embryonic-like pluripotent state via overexpression of key transcription factors. In this review, we describe how differentiation of hiPSCs to specialized cardiac cellular identities facilitates our understanding of the development and pathogenesis of CHD subtypes. We summarize the molecular and functional characterization of hiPSC-derived differentiated cells in support of normal cardiogenesis, those that go awry in CHD and other heart diseases. We illustrate how stem cell-based disease modeling enables scientists to dissect the molecular mechanisms of cell-cell interactions underlying CHD. We highlight the current state of hiPSC-based studies that are in the verge of translating into clinical trials. We also address limitations including hiPSC-model reproducibility and scalability and differentiation methods leading to cellular heterogeneity. Last, we provide future perspective on exploiting the potential of hiPSC technology as a predictive model for patient-specific CHD, screening pharmaceuticals, and provide a source for cell-based personalized medicine. In combination with existing clinical and animal model studies, data obtained from hiPSCs will yield further understanding of oligogenic, gene-environment interaction, pathophysiology, and management for CHD and other genetic cardiac disorders.

Fostering a sustainable pediatric cardiac workforce in the developing world during the current COVID-19 pandemic

: The majority of the world’s population with congenital heart disease (CHD) does not have access to corrective surgery, including 70% of those living in sub-Saharan Africa. Communicable diseases still cause significant mortality in low- and mid-income countries (LMICs), but increasingly, the burden of non-communicable diseases (NCD), such as CHD and rheumatic heart disease (RHD), has increased, creating great strain on fragile healthcare systems. The number of pediatric cardiac centers in LMICs is grossly inadequate to provide the necessary care. The unprecedented COVID-19 pandemic due to SARS-CoV-2 has only worsened the global disparities, and unfortunately has set the clock back by a few years. There has been an interruption of foreign missions and collaborations, which has affected the care of children with heart disease, and which will further increase the number on the waitlist. Much of the hard-won progress made in improving neonatal, infant, and maternal mortality may be lost due to the pandemic. Time is running out for the ambitious sustainable development goals set for 2030. At present, only 1% of developing world are vaccinated against COVID-19 with the poorest countries not expected to receive vaccine until 2023. This intervening time provides a crucial opportunity to apply “frugal innovation” by training and equipping local teams and policy makers. We employed a Gap and SWOT analysis to identify the steps needed to work towards improving children’s heart care in the developing world, all while using lessons learned from the COVID-19 pandemic.

Inactive Lifestyles Among Young Children With Innocent Murmurs or Congenital Heart Disease, Regardless of Disease Severity or Treatment.

Sedentary lifestyle morbidities are common among children with congenital heart disease (CHD). Understanding the physical activity trajectory from early childhood could enhance timing and effectiveness of interventions. We recruited 154 children (56% male) at 12 to 47 months of age for this prospective, longitudinal, observational study. Physical activity and sedentary behaviour (7-day accelerometry) and motor skill (Peabody Developmental Motor Scales-2) were assessed every 8 months until 5 years of age and then annually. Mixed-effect repeated measures regression models described outcome trajectories across study assessments. Children had innocent heart murmurs (n= 28), CHD with insignificant hemodynamics not requiring treatment (n= 47), CHD treated by catheterization or surgery without cardiopulmonary bypass (n= 31), or CHD treated surgically with bypass (n= 48). Motor skill was age appropriate (Peabody 49.0 ± 8.4), but participants had lower physical activity (143 ± 41 minutes per day) and higher sedentary time (598 ± 89 minutes per day) than healthy peers, starting at 18 months of age. Movement behaviours were not related to treatment group (P > 0.10), and physical activity was below the recommended 180 minutes per day. Over time, physical activity, sedentary time, and motor skills were primarily related to the baseline measure of each outcome (P < 0.001). Children with simple or complex CHD or innocent heart murmurs have increased risk for sedentary lifestyles. Their physical activity and sedentary behaviours are established before 2 years of age, persist until school age, and are unrelated to motor skills. These results emphasize the need for interventions targeting the youngest children seen in cardiac clinics, regardless of diagnoses of CHD or innocent murmur.

Spectrum Characteristics Analysis and Recognition of CHD Heart Sound in Five Auscultation Locations

Cardiac Auscultation is widely used in the diagnosis of congenital heart disease (CHD) due to its non-invasive and cost-effective procedure. Heart sound analysis can provide effective auxiliary diagnosis information and aid in automatically screening patients. However, there are different signal spectrum characteristics in different auscultation locations, and there are no unified standards in the selection of auscultation locations during the heart sound analysis. This paper addresses the problem of auscultation locations and the selection of spectrum characteristics in the heart sound identification of CHD patients. 385 cases of normal and CHD heart sound signals were used to extract three groups of representative spectral features: Power Spectral Density (PSD), Mel-Frequency Cepstrum Coefficients (MFCCs) and Instantaneous Frequency Cumulative(IFC) from five different auscultation locations which are Aortic area(A), Pulmonic area(P), Tricuspid area(T), Mitral area(M), and Second aortic valve area(E). Significance detections based on p-value and Gaussian kernel support vector machine (SVM) were used to test these spectrum characteristics in five auscultation locations. The results show that the spectrum energy and the difference of auscultation areas concentrated within the frequency range of 20-150Hz. There is no statistical significance in terms of the spectrum characteristics of CHD in area A (p>0.05) compared with the statistical significance in other auscultation areas (p<0.01). The classification performance of the SVM method that uses spectrum characteristics of area E was the best overall. The experiment and analysis results show that, in CHD heart sound recognition, E-area signals have the best recognition effect, signals from TMP areas could be used as a reference, and A-area signals should be used with cautions. This discovery provides a practical guide to the clinical auscultation and signal processing of Congenital Heart Disease.

US Trends in Pediatric VAD Utilization - Where are We Now?

Pediatric ventricular assist device (VAD) therapy is a rapidly changing field where devices and applications are rapidly evolving. We sought to describe some of the most recent trends in pediatric VAD use and contemporary outcomes since UNOS began collecting VAD data on all listed patients regardless of whether they survived. All children ≤21 years of age listed for isolated HT between Jan 2004 and 2019 and underwent VAD placement were identified using OPTN data. Descriptive statistics were used to characterize recent trends in VAD utilization. Waitlist survival in children with cardiomyopathy, CHD and single-ventricle heart disease were estimated using the Kaplan-Meier method. Overall, 2059 children met the study inclusion criteria of whom the median age was 11 (IQR 1, 17), median weight 38 (11,66) kg, 26% were black; 18.3 had congenital heart disease (CHD) including 5.1% with single-ventricle (SV) HD. Forty-nine percent were supported with a VAD at listing, 72% at transplant and 13% received a VAD but was not supported at listing or transplant. Overall, 64% received LVADs, 31% BIVADs, 2.5% RVADs 1.7% total artificial hearts (TAH). Implants of the Berlin Heart fell dipped sharply to 34 in 2015 after a peak of 63 but have rebounded since in the era of bivalirudin. As of 2018, the Heartware HVAD was the most commonly implanted VAD in children (N=61) followed by the Berlin Heart (N=48), CentriMag/PediMag (N=18) and Heartmate III (N=11). The fastest growing segment of VAD patients are single-ventricle patients (Figure). The total number of pediatric VADs continues to grow at a brisk pace. The most recent era has seen growth of the Heartmate III and resurgence of the Berlin Heart EXCOR, after a brief decline in 2015. Single-ventricle and Heartmate III patients represent the fastest growing segment of the VAD population.

Classification of heart sound signals in congenital heart disease based on convolutional neural network

Cardiac auscultation is the basic way for primary diagnosis and screening of congenital heart disease(CHD). A new classification algorithm of CHD based on convolution neural network was proposed for analysis and classification of CHD heart sounds in this work. The algorithm was based on the clinically collected diagnosed CHD heart sound signal. Firstly the heart sound signal preprocessing algorithm was used to extract and organize the Mel Cepstral Coefficient (MFSC) of the heart sound signal in the one-dimensional time domain and turn it into a two-dimensional feature sample. Secondly, 1 000 feature samples were used to train and optimize the convolutional neural network, and the training results with the accuracy of 0.896 and the loss value of 0.25 were obtained by using the Adam optimizer. Finally, 200 samples were tested with convolution neural network, and the results showed that the accuracy was up to 0.895, the sensitivity was 0.910, and the specificity was 0.880. Compared with other algorithms, the proposed algorithm has improved accuracy and specificity. It proves that the proposed method effectively improves the robustness and accuracy of heart sound classification and is expected to be applied to machine-assisted auscultation.

Research on Recognition of CHD Heart Sound Using MFCC and LPCC

Congenital heart disease (CHD) is a disease that seriously harms the children and family. It needs to be diagnosed and treated in time. The initial diagnosis way of CHD is cardiac auscultation in which the rich experience and expertise are needed. A kind of recognition algorism was proposed to help the initial diagnosis and screening of CHD in this work. The heart sounds were analyzed and the feature extraction by using MFCC and LPCC methods in which the frame length was 2048. The BP neural network was selected as classifier. Results show that the specificity and sensitivity of recognition ratios for CHD are 93.02% and 88.89% by using MFCC, and 86.96% and 86.96% by using LPCC respectively. The features extracted by using MFCC method are better than one by using LPCC.

Significant mortality, morbidity and resource utilization associated with advanced heart failure in congenital heart disease in children and young adults

Children with congenital heart disease (CHD) are at risk for advanced heart failure (AHF). We sought to define the mortality and resource utilization in CHD-related AHF in children and young adults. All hospitalizations in the Pediatric Health Information System database involving patients ≤21 years old with a CHD diagnosis and heart failure requiring at least 7 days of continuous inotropic support between 2004 and 2015 were included. Hospitalizations including CHD surgery were excluded. Of 465,482 CHD hospitalizations, AHF was present in 2,712 (0.6%) [58% infant, 55% male, 30% single ventricle]. AHF therapies frequently used included extracorporeal membrane oxygenation (ECMO) (15%) and cardiac transplant (16%). Ventricular assist device (VAD) support was rare (3%), although VAD use significantly increased from 2004 to 2015 (P < .0010). Hospital mortality in CHD with AHF was 26%, with higher mortality associated with single ventricle heart disease (OR 1.64, 95% CI 1.23-2.19; P = .0009), infancy (OR 1.71, 95% CI 1.17-2.5; P = .0057), non-white race (OR 1.28, 95% CI 1.04-1.59; p=0.0234), and chronic complex comorbidities (OR 1.76, 95% CI 1.34-2.30; P < .0001). Over the 11-year study period, despite the significant increase in CHD-related AHF hospitalizations (P < .0001), hospital mortality improved (P = .0011). Median hospital costs were $252,000, a 6-fold increase above those without AHF, and was primarily driven by hospital length of stay (P < .0001). AHF in children with CHD in uncommon but increasing and is associated with significant morbidity, mortality and resource utilization. Approximately 1 in 5 children do not survive to hospital discharge. Many risk factors for mortality may not be modifiable, and further study is needed to identify modifiable risk factors and improve care for this complex population.

Downregulation of microRNA-592 protects mice from hypoplastic heart and congenital heart disease by inhibition of the Notch signaling pathway through upregulating KCTD10.

Evidence has demonstrated that the microRNA (miR) may play a significant role in the development of congenital heart disease (CHD). Here, we explore the mechanism of microRNA-592 (miR-592) in heart development and CHD with the involvement of KCTD10 and Notch signaling pathway in a CHD mouse model. Cardiac tissues were extracted from CHD and normal mice. Immunohistochemistry staining was performed to detect positive expression rate of KCTD10. A series of inhibitor, activators, and siRNAs was introduced to verified regulatory functions for miR-592 governing KCTD10 in CHD. Furthermore, the effect of miR-592 on cell proliferation and apoptosis was also investigated. Downregulated positive rate of KCTD10 was observed in CHD mice. Downregulation of miR-592 would upregulate expression of KCTD10 and inhibit the activation of Notch signaling pathway, thus promote cell proliferation. This study demonstrates that downregulation of miR-592 prevents CHD and hypoplastic heart by inhibition of the Notch signaling pathway via negatively binding to KCTD10.

Developmental SHP2 dysfunction underlies cardiac hypertrophy in Noonan syndrome with multiple lentigines.

Hypertrophic cardiomyopathy is a common cause of mortality in congenital heart disease (CHD). Many gene abnormalities are associated with cardiac hypertrophy, but their function in cardiac development is not well understood. Loss-of-function mutations in PTPN11, which encodes the protein tyrosine phosphatase (PTP) SHP2, are implicated in CHD and cause Noonan syndrome with multiple lentigines (NSML), a condition that often presents with cardiac hypertrophic defects. Here, we found that NSML-associated hypertrophy stems from aberrant signaling mechanisms originating in developing endocardium. Trabeculation and valvular hyperplasia were diminished in hearts of embryonic mice expressing a human NSML-associated variant of SHP2, and these defects were recapitulated in mice expressing NSML-associated SHP2 specifically in endothelial, but not myocardial or neural crest, cells. In contrast, mice with myocardial- but not endothelial-specific NSML SHP2 expression developed ventricular septal defects, suggesting that NSML-associated mutations have both cell-autonomous and nonautonomous functions in cardiac development. However, only endothelial-specific expression of NSML-associated SHP2 induced adult-onset cardiac hypertrophy. Further, embryos expressing the NSML-associated SHP2 mutation exhibited aberrant AKT activity and decreased downstream forkhead box P1 (FOXP1)/FGF and NOTCH1/EPHB2 signaling, indicating that SHP2 is required for regulating reciprocal crosstalk between developing endocardium and myocardium. Together, our data provide functional and disease-based evidence that aberrant SHP2 signaling during cardiac development leads to CHD and adult-onset heart hypertrophy.

Does Survival on the Heart Transplant Waiting List Depend on the Underlying Heart Disease?

ObjectivesThe aim of this study was to identify differences in survival on the basis of type of heart disease while awaiting orthotopic heart transplantation (OHT). BackgroundPatients with restrictive cardiomyopathy (RCM), congenital heart disease (CHD), or hypertrophic cardiomyopathy (HCM) may be at a disadvantage while awaiting OHT because they often are poor candidates for mechanical circulatory support and/or inotropes. MethodsThe study included all adults in the Scientific Registry of Transplant Recipients database awaiting OHT from 2004 to 2014, and outcomes were evaluated on the basis of type of heart disease. The primary endpoint was time to all-cause mortality, censored at last patient follow-up and time of transplantation. Multivariate Cox proportional hazards modeling was performed to evaluate survival by type of cardiomyopathy. ResultsThere were 14,447 patients with DCM, 823 with RCM, 11,799 with ischemic cardiomyopathy (ICM), 602 with HCM, 964 with CHD, 584 with valvular disease, and 1,528 in the “other” category (including 1,216 for retransplantation). During median follow-up of 3.7 months, 4,943 patients died (1,253 women, 3,690 men). After adjusting for possible confounding variables including age, renal function, inotropes, mechanical ventilation, and mechanical circulatory support, the adjusted hazard ratios by diagnoses relative to DCM were 1.70 for RCM (95% confidence interval [CI]: 1.43 to 2.02), 1.10 for ICM (95% CI: 1.03 to 1.18), 1.23 for HCM (95% CI: 0.98 to 1.54), 1.30 for valvular disease (95% CI: 1.07 to 1.57), 1.37 for CHD (95% CI: 1.17 to 1.61), and 1.51 for “other” diagnoses (95% CI: 1.34 to 1.69). Sex was a significant modifier of mortality for ICM, RCM, and “other” diagnoses (p < 0.05 for interaction). ConclusionsIn the United States, patients with RCM, CHD, or prior heart transplantation had a higher risk for death while awaiting OHT than patients with DCM, ICM, HCM, or valvular heart disease.

Outcomes after Orthotopic Heart and Heart-Lung Transplantation for Congenital Heart Disease in Australia and New Zealand

Purpose An increasing number of patients with congenital heart disease (CHD) are reaching adulthood and a proportion of them require orthotopic heart or heart-lung transplantation. This study sets a baseline for this growing cohort in Australia and New Zealand (ANZ). Methods and Materials Between 1986 and 2011, 2177 Heart and 176 Heart-lung transplants were performed in ANZ. 99 (4.5%) of these Heart transplants, and 54 (30.7%) of these Heart-lung transplants were performed on patients >18 years of age with a primary diagnosis of CHD. Data for this study was obtained from the ANZ Cardiothoracic Organ Transplantation Registry. Results Both the ANZ CHD Heart transplant and the ANZ CHD Heart-lung transplant groups show excellent outcomes, with better survival than those reported in the ISHLT registry for any aetiology. Survival for the ANZ CHD Heart transplant group at 30 days, 1 year, 5 years and 10 years were 96%, 93%, 87% and 80% respectively. Our results show a median survival of 19.7 years (95% CI 17–22.4 years) while the ISHLT reports a median survival of 13.1 years for CHD patients and 11 years for all heart transplant patients overall. The ANZ patients had longer mean cold ischaemic times (4.2±1.4 hours) compared to the ISHLT data (3.0±1.5 hours). Similar trends were seen with the CHD Heart-lung transplant group. The survival at 30 days, 1 year, 5 years and 10 years were 93%, 76%, 51% and 43% respectively and are superior to those reported in the ISHLT data. The ANZ CHD Heart-lung transplantation cohort has a median survival of 5.9 years (95% CI 0.8–11.1 years), which is superior to the 3.9 years reported in the ISHLT for the CHD group and 4.8 years for any aetiology. Conclusions Despite longer cold ischaemic times, ANZ patients undergoing heart or heart-lung transplantation for CHD have excellent outcomes that will serve to reassure not only the CHD patients with end-stage symptoms, but also healthcare management towards developing adequate infrastructure to meet the anticipated rise in CHD patients requiring transplantation.

Diagnostic role of plasma BNP levels in neonates with signs of congenital heart disease

Only a few studies have examined the relationship of plasma BNP levels and congenital heart disease (CHD) in neonates and these mainly concern preterm neonates with patent ductus arteriosus. We aimed to investigate the diagnostic role of plasma BNP in neonates admitted in the neonatal intensive care unit, (NICU), with signs of congenital heart disease (CHD). Prospective assessment of plasma BNP levels in 75 consecutive neonates with suspected CHD (heart murmur, respiratory distress, or cyanosis), admitted in the NICU of our university hospital. The final diagnosis was done with echocardiography. Haemodynamically significant Left to Right shunts, (hsLtR), were found in 29 neonates, insignificant LtR shunts in 22, no heart disease in 15 and cyanotic heart disease in 9. BNP levels were significantly higher in neonates with hsLtR shunts vs. all other groups (logBNP 2.9 ± 0.5 pg/ml vs. 1.5 ± 0.4 pg/ml vs. 1.5 ± 0.3 pg/ml vs. 1.6 ± 0.2 pg/ml, p < 0.0001). Plasma BNP levels > 132.5 pg/ml had 93.1% sensitivity and 100% specificity for diagnosing hsLtR shunts (accuracy 99.6%). Plasma BNP is a reliable test for diagnosing hsLtR shunts in the NICU. This will alert the neonatologist for ordering an echocardiographic examination, or if the latter is not available, for transferring the neonate to an appropriate tertiary centre with neonatal-paediatric cardiology facilities. Normal BNP levels imply the absence of a significant LtR shunt, but may not exclude cyanotic heart disease.

The mechanism of &lt;I&gt;TBX5&lt;/I&gt; abnormal expression in simple con-genital heart disease

To explore the mechanism of TBX5 abnormal expression in simple congenital heart disease (CHD), 100 CHD venous blood, 50 CHD heart tissues, and 5 non-CHD heart tissues were involved in this study. The mutation and methylation in the 1 200 bp region upstream of TBX5 gene were detected by high-performance liquid chromatography (DHPLC) and methylation-sensitive restriction endonuclease (MS-RE), respectively. The binding site of NKX2-5 to Tbx5 predicted by P-MATCH software was validated by EMSA (Electrophoretic mobility shift assay). Tbx5 gene expression in mouse cardiac muscle cell H9C2(2-1) transfected with NKX2-5 expression vector was evaluated. No mutation was found in all patients. Both non-CHD and CHD heart tissues had the same methylation in the two CpG islands. Exogenous Nkx2-5 efficiently activated the transcription of the endogenous Tbx5 gene in H9C2 (2-1) cells. EMSA showed that the special binding band appeared when Nkx2-5 existed. These results indicates that the down expression of TBX5 might not be caused by mutation and methylation in the 1 200 bp region upstream of gene, and might be regulated by abnormal expression of NKX2-5 gene in heart muscle of CHD.

Maternal experiences making a decision about heart surgery for their young children with congenital heart disease

The aim of this study was to investigate the essence of the experience of mothers during the decision-making process when facing their less than three-year-old child undergoing heart surgery due to congenital heart disease (CHD). In this phenomenological study in Taiwan nine mothers were interviewed in their homes. They were invited to share their experience of family interactions and relationships while facing a decision about their child's heart surgery. The interviews were recorded and transcribed for further analysis according to Colaizzi's phenomenological methodology. The essence of the maternal experience themes during the decision-making process included (i) understanding the surgery step by step, (ii) role pressure, (iii) constructing care-taking ability, (iv) endeavouring to maintain family functioning while preparing for surgery and (v) deliberate consideration to make the correct decision. When parents face their child having CHD and plan heart surgery, the whole family is living through a stressful decision-making process. According to the results of this study, it is obvious that the caregivers and their whole families experience psychological distress, role reorganization and remodelling of family functioning. The results of this study provide evidence-based essential knowledge that will assist the management of such decision-making processes and help to prepare the child and the family to have confidence in the heart surgery.

Genetic analysis of chromosome 22q11.2 markers in congenital heart disease.

Congenital heart disease (CHD) is a common cardiac defect found in infants and children. Despite advances in diagnosis and treatment, our understanding of the causative mechanism and etiology of CHD is limited. To determine the genetic etiology of CHD, we selected 11 consecutive short tandem-repeat polymorphic (STRP) markers located in the interval of the 22q11.2 region to perform genotype analysis on a large number of CHD patients (>120) and their normal relatives (>220). The results show that as regards the distribution of allelic size and frequency of these STRP markers, there were no significant differences between the CHD patients and the normal volunteers. This indicates that there is no linkage disequilibrium with these markers in CHD. In the level of heterozygosity for each marker in nonsyndromic CHD and conotruncal heart defect (CTD), there were no significant differences between the two populations. In syndromic CHD, the level of heterozygosity for D22S1648 was significantly lower than that observed in the unaffected population (chi(2) = 11.25; P = 0.001). This suggests that there may be a deletion at the D22S1648 locus, and the low heterozygosity of D22S1648 indicates that this marker can be used as a genetic marker for detecting microdeletions in 22q11.2. With the use of fluorescence in situ hybridization (FISH) and real-time quantitative polymerase chain reaction (PCR) performed on syndromic patients, we confirmed the molecular results.