Atrioventricular Septal Defect Research Articles

Risk of infective endocarditis after hybrid melody mitral valve replacement in infants: the French experience.

Surgical management of mitral valve disease is challenging in infants <1 year old. We aimed at reviewing the French experience with Melody mitral valve replacement in critically ill infants. A retrospective cohort study reporting the French experience with Melody mitral valve replacement. Seven symptomatic infants [complete atrioventricular septal defect (n = 4, Down syndrome: n = 3), hammock valve (n = 3)] underwent Melody mitral valve replacement [age: 3 months (28 days to 8 months), weight: 4.3 kg (3.2-6.4 kg)] because of severe mitral valve regurgitation (6) or mixed valve disease (1) and 14 mm (11-16 mm) mitral valve annulus. In 2 patients whose valve was felt irreparable, Melody mitral valve replacement was performed straightaway. The others underwent 2 (1-3) previous attempts of valve repair; 3 were on extracorporeal membrane oxygenation. Melody mitral valve replacement led to competent valve and low gradient [3 mmHg, (1-4 mmHg)]. One patient died 3 days post-implant from extracorporeal membrane oxygenation-related stroke. Of the 6 discharged home patients, 3 (50%) were readmitted for a definite diagnosis (1) or high suspicion (2) of infective endocarditis, of which 2 died. Over the follow-up, 1 underwent balloon expansions of the valve at 9- and 16-months post-implant, and mechanical mitral valve replacement at 2 years; another is currently planned for transcatheter Melody valve dilation. Melody mitral valve replacement may be considered in selected infants with small mitral valve annulus as an alternative to mechanical mitral valve replacement. Our experience highlights a high-risk of late infective endocarditis that deserves further consideration.

Epidemiology of Postoperative Junctional Ectopic Tachycardia in Infants Undergoing Cardiac Surgery

BackgroundJunctional ectopic tachycardia (JET) complicates congenital heart surgery in 2% to 8.3% of cases. JET is associated with postoperative morbidity in single-center studies. We used the Pediatric Cardiac Critical Care Consortium data registry to provide a multicenter epidemiologic description of treated JET. MethodsThis is a retrospective study (February 2019-August 2022) of patients with treated JET. Inclusion criteria were (1) <12 months old at the index operation, and (2) treated for JET <72 hours after surgery. Diagnosis was defined by receiving treatment (pacing, cooling, and medications). A multilevel logistic regression analysis with hospital random effect identified JET risk factors. Impact of JET on outcomes was estimated by margins/attributable risk analysis using previous risk-adjustment models. ResultsAmong 24,073 patients from 63 centers, 1436 (6.0%) were treated for JET with significant center variability (0% to 17.9%). Median time to onset was 3.4 hours, with 34% present on admission. Median duration was 2 days (interquartile range, 1-4 days). Tetralogy of Fallot, atrioventricular canal, and ventricular septal defect repair represented >50% of JET. Patient characteristics independently associated with JET included neonatal age, Asian race, cardiopulmonary bypass time, open sternum, and early postoperative inotropic agents. JET was associated with increased risk-adjusted durations of mechanical ventilation (incidence rate ratio, 1.6; 95% CI, 1.5-1.7) and intensive care unit length of stay (incidence rate ratio, 1.3; 95% CI, 1.2-1.3), but not mortality. ConclusionsJET is treated in 6% of patients with substantial center variability. JET contributes to increased use of postoperative resources. High center variability warrants further study to identify potential modifiable factors that could serve as targets for improvement efforts to ameliorate deleterious outcomes.

Two-Dimensional and Doppler trans-thoracic echocardiographic patterns of suspected pediatric heart diseases at Tibebe--Ghion specialized Teaching Hospital and Adinas General Hospital, Bahir Dar, North-west Ethiopia:-An experience from an LMIC.

Transthoracic Echocardiography is the first-line, non-invasive, and accessible imaging modality to evaluate heart disease anatomy, physiology, and hemodynamics. We aim to describe the trans-thoracic echocardiography pattern of pediatric heart diseases and reasons for referral in children referred to Bahir Dar University Tibebe-Ghion Hospital and Adinas General Hospital. A descriptive cross-sectional study of the archived Transthoracic, Two Dimensional, and Doppler Echocardiography assessments of children from birth to fifteen years of age performed between June 2019 to May 2023 was done. Data were collected retrospectively from February 01, 2023 -May 31, 2023. Categorical variables like gender, referral reasons for echocardiography, and patterns of pediatric heart lesions were analyzed in the form of proportions and presented in tables and figures. Discrete variables including age were summarized as means (SD) and medians(IQR). Out of 3,647 Children enrolled; 1,917 (52.6%) were males and 1,730 (47.4%) were females. The median (IQR) age of children enrolled was 24 months (5 to 96). Cardiac murmur (33%) was the most common reason for echocardiography followed by, Respiratory Distress (18%), Syndromic Child (15%), easy fatigability/ Diaphoresis (14.3%), congestive heart failure (14%), and rheumatic fever (13.2%). Congenital heart defect (CHD) accounts for 70% of all heart diseases, followed by rheumatic heart disease (21%). Isolated ventricular septal defect(VSD) was the most common CHD (21%) followed by isolated Patent ductus arteriosus (15%), isolated atrial septal defect (10%), Isolated atrioventricular septal defect (6%) and isolated pulmonary stenosis (5%). Cyanotic CHD accounts for 11.5% of all heart diseases. Tetralogy of Fallot (30%), d-TGA (20%), and double outlet right ventricle (19%) were the most common cyanotic CHDs. In our study, congenital heart lesions are the most common diagnosis and cardiac murmurs are the most common presenting reasons for echocardiography evaluation.

Preoperative Feeding Fortification Among Infants with Congenital Heart Disease is Associated with Higher Growth Velocity in the First 30 Days Post-repair and Lower BMI Percentile for Age at 10 Years: A Retrospective Cohort Study.

It remains unclear how preoperative nutrition fortification impacts postoperative growth trajectories and nutritional status among infants with congenital heart disease. A single center retrospective cohort study was performed to evaluate measures of growth among patients who underwent cardiac repair at 0-18months of age for atrial septal defect, ventricular septal defect, atrioventricular septal defect, or tetralogy of Fallot. Cohorts were analyzed at 0-30 and 31-60days post-repair as well as at 2, 5, and 10years of age. Records of 24 patients who received fortified nutrition and 60 patients who received unfortified nutrition preoperatively were reviewed. Those with fortified nutrition had higher growth velocities in the first 30days post-repair compared to those with unfortified nutrition: 28.4 (23.8-83.3) grams per day versus 16.7 (7.1-21.4) grams per day, p = 0.004. Weight percentile for age was higher in the unfortified group at 2, 5, and 10years of age (p = 0.02, p = 0.045, and p = 0.01). Body mass index (BMI) percentile for age was higher in the unfortified group at 5 and 10years of age (p = 0.045 and p = 0.02) with a trend toward higher prevalence of either overweight or obesity compared to the fortified group (p = 0.13). reoperative nutrition fortification among infants with congenital heart disease is associated with higher growth velocity in the first 30days post-repair and lower BMI percentile for age at 10years. Further studies are needed to evaluate the association between preoperative nutrition fortification and postoperative outcomes, nutritional status, and prevalence of obesity in adolescence and adulthood.

Effect of deletion of the protein kinase PRKD1 on development of the mouse embryonic heart.

Congenital heart disease (CHD) is the most common congenital anomaly, with an overall incidence of approximately 1% in the United Kingdom. Exome sequencing in large CHD cohorts has been performed to provide insights into the genetic aetiology of CHD. This includes a study of 1891 probands by our group in collaboration with others, which identified three novel genes-CDK13, PRKD1, and CHD4, in patients with syndromic CHD. PRKD1 encodes a serine/threonine protein kinase, which is important in a variety of fundamental cellular functions. Individuals with a heterozygous mutation in PRKD1 may have facial dysmorphism, ectodermal dysplasia and may have CHDs such as pulmonary stenosis, atrioventricular septal defects, coarctation of the aorta and bicuspid aortic valve. To obtain a greater appreciation for the role that this essential protein kinase plays in cardiogenesis and CHD, we have analysed a Prkd1 transgenic mouse model (Prkd1em1) carrying deletion of exon 2, causing loss of function. High-resolution episcopic microscopy affords detailed morphological 3D analysis of the developing heart and provides evidence for an essential role of Prkd1 in both normal cardiac development and CHD. We show that homozygous deletion of Prkd1 is associated with complex forms of CHD such as atrioventricular septal defects, and bicuspid aortic and pulmonary valves, and is lethal. Even in heterozygotes, cardiac differences occur. However, given that 97% of Prkd1 heterozygous mice display normal heart development, it is likely that one normal allele is sufficient, with the defects seen most likely to represent sporadic events. Moreover, mRNA and protein expression levels were investigated by RT-qPCR and western immunoblotting, respectively. A significant reduction in Prkd1 mRNA levels was seen in homozygotes, but not heterozygotes, compared to WT littermates. While a trend towards lower PRKD1 protein expression was seen in the heterozygotes, the difference was only significant in the homozygotes. There was no compensation by the related Prkd2 and Prkd3 at transcript level, as evidenced by RT-qPCR. Overall, we demonstrate a vital role of Prkd1 in heart development and the aetiology of CHD.

Efficacy of atrioventricular valve regurgitation in the first trimester for the diagnosis of atrioventricular septal defect.

To investigate the efficacy of atrioventricular valve regurgitation (AVVR) for predicting atrioventricular septal defect (AVSD) in the first trimester. We performed a prospective observational study, screening for complicated congenital heart diseases and AVVR in fetuses at 11 to 13+6 weeks of gestation by advanced dynamic flow in four-chamber view and three-vessel-trachea view. 43 549 fetuses at 11 to 13+6 weeks of gestation were screened by echocardiography, of which 37 cases were diagnosed with AVSD, including complete AVSD (31 cases), intermediate AVSD (3 cases) and partial AVSD (1 cases), undiagnosed intermediate AVSD (2 cases), and misdiagnosed case (2 cases). AVVR was observed in 34 cases (34/37) in the first trimester, 59. 46% (22/37) nuchal translucency greater than 95th percentile, 29. 73% (11/37) absence of nasal bone, 32. 43% (12/37) ductus venosus A wave inversion, and 40. 54% (15/37) had tricuspid regurgitation. The sensitivity of common AVVR in predicting AVSD is better than other ultrasonic indexes. AVVR can be used as an ultrasonic indicator to predict AVSD in the first trimester, which is beneficial to detect AVSD.

Tricuspid mechanical valve replacement for severe tricuspid stenosis in a child who underwent surgical correction of complete atrioventricular septal defect, a rare long-term complications

BackgroundComplete atrioventricular septal defect is a complicated congenital heart malformations, and surgical correction is the best treatment, the severe tricuspid stenosis is a rare long-term complication after the surgery.Case presentationWe report a case with the complication of severe tricuspid stenosis 7 years after the surgical correction of complete atrioventricular septal defect in a child. Then the patient underwent tricuspid mechanical valve replacement, Glenn, atrial septostomy, and circumconstriction of the right pulmonary artery.ConclusionsThe patient recovered successfully with good short-term.

Cardioinhibitory syncope 2b with 48-second pause in a patient with Down Syndrome and corrected AV septal defect: Description of the case and therapeutic plan

Cardioinhibitory syncope 2b with 48-second pause in a patient with Down Syndrome and corrected AV septal defect: Description of the case and therapeutic plan

An Unusual Presentation of Partial Atrioventricular Canal Defect in an Elderly Woman

A partial atrioventricular canal defect (PAVCD) is a form of endocardial cushion defect. It’s a rare congenital cardiac malformation, few reported patients have survived into the seventh decade of life. A 71-year-old female with a history of diabetes and hypertension was admitted for heart failure (HF) symptoms. Transthoracic echocardiography revealed a left to right shunt in the basal portion of the interatrial septum, 19mm ostium primum atrial septal defect (ASD), a mitral valve cleft, and severe mitral valve regurgitation. PAVCD consists of an ostium primum ASD and the dividing of the common atrioventricular (AV) valve into 2 separate AV orifices, resulting in a so-called cleft in the mitral valve. The ventricular septum is intact. Echocardiography is the key tool for diagnosis and anatomic classification. Surgical repair is recommended in adults with primum ASDs causing impaired functional capacity, right atrial or right ventricular enlargement, and left-to-right shunt without cyanosis, as long as systolic pulmonary artery pressures are lower than 50% of systemic pressures. Reconstructive surgery includes, in addition to the closure of the interatrial septum, a suturing of the mitral cleft. The estimated mean age at death of the patients with ostium primum ASD is about 40 years. The objective of this clinical case is to highlight the good clinical tolerance of atrial shunts and the anatomical particularities in the PAVCD.

Association of tetralogy of Fallot and complete atrioventricular canal: a single-centre 40-year experience.

Outcome data in tetralogy of Fallot (ToF) and complete atrioventricular canal (CAVC) are limited. We report our experience for over 40 years in this patient population. Single-centre, retrospective analysis of patients who underwent surgical repair with the diagnosis of ToF-CAVC from 1979 to 2022, divided into 2 different periods and compared. A total of 116 patients were included: 1979-2007 (n = 61) and 2008-2021 (n = 55). Balanced CAVC (80%) and Rastelli type C CAVC (81%) were most common. Patients in the later era were younger (4 vs 14 months, P < 0.001), fewer had trisomy 21 (60% vs 80%, P = 0.019) and fewer had prior palliative prior procedures (31% vs 43%, P < 0.001). In the earlier era, single-patch technique was more common (62% vs 16%, P < 0.001), and in recent era, double-patch technique was more common (84% vs 33%, P < 0.001). In the earlier era, right ventricular outflow tract was most commonly reconstructed with transannular patch (51%), while in more recent era, valve-sparing repairs were more common (69%) (P < 0.001). In-hospital mortality was 4.3%. The median follow-up was 217 and 74 months for the first and second eras. Survival for earlier and later eras at 2-, 5- and 10-year follow-up was (85.1%, 81.5%, 79.6% vs 94.2%, 94.2%, 94.2% respectively, log-rank test P = 0.03). The surgical approach to ToF-CAVC has evolved over time. More recently, patients tended to receive primary repair at younger ages and had fewer palliative procedures. Improved surgical techniques allowing for earlier and complete repair have shown a decrease in mortality, more valve-sparing procedures without an increase in total reoperations. Presented at the 37th EACTS Annual Meeting, Vienna, Austria.

Antifungal medication use during early pregnancy and the risk of congenital heart defects in the National Birth Defects Prevention Study, 1997-2011.

Fungal infections are common among pregnant people. Recent studies suggest positive associations between oral antifungals used to treat fungal infections and congenital heart defects (CHDs). We estimated associations between first trimester antifungal use and 20 major, specific CHDs using data from the National Birth Defects Prevention Study (NBDPS), a multi-site, case-control study that included pregnancies with estimated delivery dates from October 1997 through December 2011. Infants with CHDs ("cases") were ascertained from 10 birth defect surveillance programs. Live born infants without major birth defects ("controls") were randomly selected from birth records or hospital discharge lists. First trimester antifungal use was self-reported via maternal interview. We estimated adjusted odds ratios (AORs) and 95% confidence intervals (CIs) using logistic regression with Firth's penalized likelihood. First trimester antifungal use was reported by 148/11,653 (1.3%) case and 123/11,427 (1.1%) control participants. We estimated AORs for 12 CHDs; six had AORs >1.5 (tetralogy of Fallot, double outlet right ventricle with transposition of the great arteries [DORV-TGA], atrioventricular septal defect, hypoplastic left heart syndrome, pulmonary atresia, muscular ventricular septal defect), and one (pulmonary valve stenosis) had an AOR <0.7. All CIs included the null, except for DORV-TGA. First trimester antifungal use was rare. We observed some positive associations for several specific CHDs in our analysis, although the CIs largely included the null. Results do not support a large increase in risk, but smaller increases in risk for certain CHD cannot be ruled out.

Congenital septal defects in Karachi, Pakistan: an update of mutational screening by high-resolution melting (HRM) analysis of MTHFR C677T

BackgroundCongenital heart defects (CHDs) are the heart structural malformations present at birth. Septal defects account for 40% of CHD, including atrial, ventricular and atrioventricular septal defects. In Pakistan, the prevalence of CHD is 3.4 in 1000, and a study estimated that 60,000 babies are born with CHD annually. Methylenetetrahydrofolate reductase (MTHFR), a chief enzyme, involved in the folate metabolism. The missense mutation, C677T (rs1801133), exists in MTHFR gene, results in a MTHFR thermolabile variant having low enzymatic activity. The study is aim to identify the MTHFR C677T variant association with septal defects.MethodsSamples of 194 CHD patients (age X¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\overline{X }\\hspace{0.17em}$$\\end{document}= 5.8 ± 5.1) and 50 normal echo controls (age X¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\overline{X }\\hspace{0.17em}$$\\end{document}= 6.0 ± 4.9), confirmed by pediatric consultant, were collected. Extracted DNA, quantified by agarose gel electrophoresis and nanodrop, was screened for SNP by high-resolution melting (HRM). Further, HRM results were confirmed using restriction analysis and sequencing. HRM was simply and precisely genotyped the samples within 3 h at low cost.ResultsGenotypic data suggested that heterozygous mutant (CT) was frequent in congenital septal defect patients (0.26) which was higher than controls (0.143), p > 0.05. Mutant (TT) genotype was not found in this study.Conclusionsrs1801133 has lack of significant association with congenital septal defects. The absence of TT genotype in this study suggesting the role of natural selection in targeted population. HRM is an easy, fast and next generation of PCR, which may be used for applied genomics.

Genetic analysis of the false positive trisomy 7 and false negative trisomy 18 by NIPT-PLUS

To explore the cause of inconsistency between the results of trisomy 7 by expanded non-invasive prenatal testing (NIPT-PLUS) and trisomy 18 by prenatal diagnosis. A pregnant woman who received genetic counseling at Jiaozuo Maternal and Child Health Care Hospital on July 5, 2020 was selected as the study subject. NIPT-PLUS, systematic ultrasound and interventional prenatal testing were carried out. The middle segment and root of umbilical cord, center and edge of the maternal and fatal surface of the placenta were sampled for the validation by copy number variation sequencing (CNV-seq). The result of NIPT-PLUS indicated that the fetus has trisomy 7. Systematic ultrasound has shown multiple malformations including atrioventricular septal defect, horseshoe kidney, and rocker-bottom feet. However, QF-PCR, chromosomal karyotyping analysis, and CNV-seq of amniotic fluid samples all showed that the fetus was trisomy 18. Validation using multiple placental samples confirmed that the middle segment of the umbilical cord contains trisomy 18, the center of the placenta contained trisomy 7, and other placental sites were mosaicism for trisomy 7 and trisomy 18. Notably, the ratio of trisomy 18 became lower further away from the umbilical cord. The false positive results of trisomy 7 and false negative trisomy 18 by NIPT-PLUS was probably due to the existence of placental mosaicism. Strict prenatal diagnosis is required needed aneuploidy is detected by NIPT-PLUS to exclude the influence of placental mosaicisms.

Percutaneous Closure of Hemodynamically Significant Postoperative Residual Ventricular Septal Defects.

The experience with percutaneous closure of postoperative residual ventricular septal defects (VSDs) is expanding with improved device technology and techniques. To report our experience with percutaneous closure of residual VSDs after cardiac surgeries. Retrospective clinical data review of patients who had percutaneous closure of postoperative residual VSDs at our institution between 2010 and 2022. Patients' demographics, procedural, and follow-up data were looked at. Twelve patients (50% males) with a median age of 9.2years (range 0.9-22) were identified. Baseline surgeries were 8 tetralogy of Fallot corrections, 2 pulmonary bandings for large muscular VSD (mVSD) including 1 coarctation repair, 1 atrioventricular septal defect repair, 1 sub-aortic membrane resection-induced iatrogenic VSD, 1 isolated VSD closure, and 1 additional mVSD. Median duration between baseline surgery and percutaneous VSD closure was 2.2years (range 0.2-8.3). Residual VSD shunting was secondary to surgical patch leakage in 8/12 patients. The median angiographic defect diameter was 6.8mm (range 4.8-14). The defect was balloon-calibrated in 3/12 patients. Defects were tackled retrogradely in 3/9 patients. Amplatzer Membranous VSD occluder (n = 1), Lifetech Multifunctional (n = 5), Membranous (n = 1) and muscular VSD occluders (n = 2) and Occlutech Membranous (n = 1) and Muscular (n = 2) VSD occluders were used. The procedure was successful in 10/12 patients. Two devices embolized to the pulmonary artery and were snare-retrieved. Both patients were referred for surgery. The median follow-up was 1.3years (range 0.1-12). Six-month ultrasound showed one trivial residual shunt and one mild right ventricular outflow obstruction. One patient is receiving targeted therapy for pulmonary hypertension at 2years of follow-up. Transcatheter closure of postoperative residual VSDs is a feasible yet challenging intervention. Procedural complications can be encountered.

The detailed profile of congenital heart diseases in 254 children with Down syndrome in Saudi Arabia

BackgroundDown syndrome is the most common chromosomal abnormality in humans. It is associated with several congenital anomalies, including a spectrum of congenital heart diseases. Understanding the true prevalence and distribution of congenital heart diseases is essential for health resource planning, outcomes, and family counseling.This study aimed to assess the prevalence and distribution of congenital heart disease in children with Down syndrome. It is a retrospective cohort review that included all patients treated at King Abdulaziz University Hospital. Frequencies were estimated using the SPSS software and comparisons were made using Student’s t test.ResultsThe ages of the 254 subjects ranged from less than 1 year to 53 years. Of these, 44.5% were female and 40.6% were Saudi nationals. Congenital heart disease was present in 66.5% with a significant difference between Saudi nationals 44.6%) and non-Saudi nationals 71.5% (P = 0.01). The atrioventricular septal defect was the most common pathology, representing 33.1% of all congenital heart diseases followed by perimembranous ventricular septal defect 18.9%, and right ventricular pathology 10.2%.ConclusionThe prevalence of congenital heart diseases in Saudi children with Down Syndrome is similar to that reported worldwide. Septal defects and right-sided pathologies are the dominant forms of congenital heart diseases, with atrioventricular septal defect and perimembranous ventricular septal defect representing the most common pathologies.

Outcomes and characteristics in term infants with necrotising enterocolitis and CHD.

CHD is a significant risk factor for the development of necrotising enterocolitis. Existing literature does not differentiate between term and preterm populations. Long-term outcomes of these patients are not well understood. The aim was to investigate the baseline characteristics and outcomes of term normal birth weight infants with CHD who developed necrotising enterocolitis. A retrospective review was performed of infants from a single tertiary centre with CHD who developed necrotising enterocolitis of Bell's Stage 1-3, over a ten-year period. Inclusion criteria was those born greater than 36 weeks' gestation and birth weight over 2500g. Exclusion criteria included congenital gastro-intestinal abnormalities. Sub-group analysis was performed using Fisher's exact test. Twenty-five patients were identified, with a median gestational age of 38 weeks. Patients with univentricular physiology accounted for 32% (n = 8) and 52% of patients (n = 13) had a duct-dependent lesion. Atrioventricular septal defect was the most common cardiac diagnosis (n = 6, 24%). Patients with trisomy 21 accounted for 20% of cases. Mortality within 30 days of necrotising enterocolitis was 20%. Long-term mortality was 40%, which increased with increasing Bell's Stage. In total, 36% (n = 9) required surgical management of necrotising enterocolitis, the rate of which was significantly higher in trisomy 21 cases (p < 0.05). Not previously described in term infants is the high rate of trisomy 21 and atrioventricular septal defect. This may reflect higher baseline incidence in our population. Infants with trisomy 21 were more likely to develop surgical necrotising enterocolitis. Mortality at long-term follow-up was high in patients with Bell's Stage 2-3.

Human Genetics of Atrioventricular Septal Defect.

Atrioventricular septal defects (AVSD), also known as a common atrioventricular canal (CAVC), are clinically severe heart malformations that affect about 1 out of every 2100 live births. AVSD makes up about 5% of all congenital heart defects. AVSD is associated with cytogenetic disorders such as Down syndrome and numerous other rare genetic syndromes, but also occurs as a simplex trait. Studies in mouse models have identified over 100 genetic mutations that have the potential to cause an AVSD. However, studies in humans indicate that AVSD is genetically heterogeneous, and that the cause in humans is very rarely a single-gene defect. Familial cases do occur albeit rarely, usually with autosomal dominant inheritance and variable expression. In addition, the frequent occurrence of AVSD in some syndromes with known genetic causes such as heterotaxy syndrome points to additional genes/pathways that increase AVSD risk. Accordingly, while the genetic underpinnings for most AVSD remain unknown, there have been advances in identifying genetic risk factors for AVSD in both syndromic and nonsyndromic cases. This chapter summarizes the current knowledge of the genetic basis for AVSD.

Molecular Pathways and Animal Models of Atrioventricular Septal Defect.

The development of a fully functional four-chambered heart is critically dependent on the correct formation of the structures that separate the atrial and ventricular chambers. Perturbation of this process typically results in defects that allow mixing of oxygenated and deoxygenated blood. Atrioventricular septal defects (AVSD) form a class of congenital heart malformations that are characterized by the presence of a primary atrial septal defect (pASD), a common atrioventricular valve (cAVV), and frequently also a ventricular septal defect (VSD). While AVSD were historically considered to result from failure of the endocardial atrioventricular cushions to properly develop and fuse, more recent studies have determined that inhibition of the development of other components of the atrioventricular mesenchymal complex can lead to AVSDs as well. The role of the dorsal mesenchymal protrusion (DMP) in AVSD pathogenesis has been well-documented in studies using animal models for AVSDs, and in addition, preliminary data suggest that the mesenchymal cap situated on the leading edge of the primary atrial septum may be involved in certain situations as well. In this chapter, we review what is currently known about the molecular mechanisms and animal models that are associated with the pathogenesis of AVSD.

Echocardiographic Findings of Children with Down Syndrome

Objective: Down syndrome is the most common well-known chromosomal disorder. The incidence of congenital heart disease (CHD) in these patients is high and it is the most important cause of mortality. In this study, we reviewed the comorbid CHDs and their characteristics in patients with the diagnosis of Down syndrome. We compared our results with the results of studies conducted in different regions of our country in different years. Materials and Methods: Between January 2020 and December 2022, data from a total of 385 patients (175 females, 210 males) with Down syndrome were evaluated. The age of the mothers at the time of delivery and the availability of prenatal diagnosis information in accessible patients were determined. Results: Of 385 patients with Down syndrome, 38.2% (n=147) had CHD. Among patients with CHD, 57 patients had atrioventricular septal defect (AVSD) (38.7%), 35 patients had perimembranous ventricular septal defect (23.8%), 24 patients had secundum atrial septal defect (16.3%), 8 patients had patent ductus arteriosus (5.4%), and 10 patients without AVSD had CHD with multiple left-to-right shunts (6.8%). The most common cyanotic CHD was tetralogy of Fallot (n=7, 4.7%). Complete AVSD was present in 63.1% of AVSD patients. CHD was present in 36.2% of boys and 40.6% of girls. Among all female patients, 17.1% had AVSD, while this rate was 12.8% among all male patients (p&lt;0.05). The mean maternal age at delivery was 32.59±6.9 (17-48) years. It was found that children with Down syndrome whose mothers had a maternal age of 33.5 years and above had a lower rate of CHD. Of the 170 mothers for whom prenatal diagnosis information was available, 58.2% (n=99) had a prenatal diagnosis. Conclusion: Prenatal diagnosis opportunities have increased and become widespread over the years. However, no significant change was observed in the rates of CHD, which is most frequently responsible for mortality in children with Down syndrome. It is appropriate for every expectant mother with a prenatal diagnosis to be referred for fetal echocardiography or postnatal transthoracic echocardiography.

Clinical Presentation and Therapy of Atrioventricular Septal Defect.

Atrioventricular septal defects (AVSDs) consist of a number of cardiac malformations that result from abnormal development of the endocardial cushions. AVSDs occur in 0.19 of 1000 live births and constitute 4-5 % of congenital heart defects. AVSDs can be categorized as incomplete (or partial) or complete, and intermediate or transitional.