Molecular Pathways and Animal Models of Ebstein's Anomaly.

Ebstein's anomaly is a congenital malformation of the tricuspid valve characterized by abnormal attachment of the valve leaflets, resulting in varying degrees of valve dysfunction. The anatomic hallmarks of this entity are the downward displacement of the attachment of the septal and posterior leaflets of the tricuspid valve. Additional intracardiac malformations are common. From an embryological point of view, the cavity of the future right atrium does not have a direct orifice connected to the developing right ventricle. This chapter provides an overview of current insight into how this connection is formed and how malformations of the tricuspid valve arise from dysregulation of molecular and morphological events involved in this process. Furthermore, mouse models that show features of Ebstein's anomaly and the naturally occurring model of canine tricuspid valve malformation are described and compared to the human model. Although Ebstein's anomaly remains one of the least understood cardiac malformations to date, the studies summarized here provide, in aggregate, evidence for monogenic and oligogenic factors driving pathogenesis.

Molecular Pathways and Animal Models of Tricuspid Atresia and Univentricular Heart.

The process of valve formation is a complex process that involves intricate interplay between various pathways at precise times. Although we have not completely elucidated the molecular pathways that lead to normal valve formation, we have identified a few major players in this process. We are now able to implicate TGF-ß, BMP, and NOTCH as suspects in tricuspid atresia (TA), as well as their downstream targets: NKX2-5, TBX5, NFATC1, GATA4, and SOX9. We know that the TGF-ß and the BMP pathways converge on the SMAD4 molecule, and we believe that this molecule plays a very important role to tie both pathways to TA. Similarly, we look at the NOTCH pathway and identify the HEY2 as a potential link between this pathway and TA. Another transcription factor that has been implicated in TA is NFATC1. While several mouse models exist that include part of the TA abnormality as their phenotype, no true mouse model can be said to represent TA. Bridging this gap will surely shed light on this complex molecular pathway and allow for better understanding of the disease process.

The first post-natal clinical description of true mosaic complete tetrasomy 21: A case report.

Tetrasomy 21 is a rare occurrence. Only 14 cases have been reported in the literature, 8 of which are partial tetrasomy cases and 6 which are complete tetrasomy cases. Of the incidences, no proband with true complete tetrasomy 21 has survived the neonatal period. We report complete mosaic tetrasomy 21 in a female infant with the typical Down syndrome phenotype, including Hirschsprung's disease and atrioventricular (AV) canal defect. This is in contrast to cases of partial tetrasomy 21, which often have an atypical trisomy 21 presentation and multiple nonspecific traits, including short stature, microcephaly, and developmental delays. This case demonstrates the difference in clinical presentation between the partial and complete subtype of tetrasomy 21 and provides the first postnatal clinical picture of an infant with true mosaic complete tetrasomy 21.

Novel Transcatheter Approach to Treat Primum Atrial Septal Defects.

•Degenerative common AVC defect can mimic rheumatic MV stenosis.•Closure of primum ASD can be achieved percutaneously.•Live 3D multiplanar TEE is crucial for procedural guidance.

Ellis van creveld syndrome: Cardiac anomalies and anesthetic implications.

Ellis-Van Creveld syndrome (EVC), also known as mesoectodermal dysplasia, is a rare autosomal recessive disorder with a tetrad of clinical features, comprising dwarfism, polydactyly, ectodermal dysplasia with sparse hair, hypoplastic nails and enamel, hypodontia and conical teeth and congenital heart disease (CHD). We report an 18-year-old girl with short stature and polydactyly, who got admitted to our hospital with shortness of breath on exertion for the last 2 years. On echocardiography, a partial atrioventricular canal (AV canal) defect was diagnosed, which was repaired surgically. The patient had an uneventful perioperative period.

Echocardiographic Study of Ventricular Septal Defect in 1- to 12-Year-Old Children Visiting a Tertiary Care Center in Patna, India.

Background Symptoms of serious heart problems present at birth often appear during the first few days, weeks, or months of a child's life. Shunt formation between the left and right ventricle is a crucial component of the pathophysiology of ventral septal defects. Objectives We aim to determine the most frequent types of ventricular septal defect (VSD) by echocardiography and whether there is any gender variation in the type of ventricular septal defect. Material and methods A total of 100 children who were clinically suspected of or diagnosed with VSD at the age of 1-12 years were enrolled in this study. The septum of the atrioventricular (AV) canal, the muscular septum, and the parietal band of the distal conal septum were evaluated by color Doppler. Ventricular septal defect (VSD) size and kind are similarly impacted by the 2D echo mode. The size and site of the VSD, associated congenital anomaly, and significant morphological changes in ventricular cavities, gender discrimination, and relation-specific types of ventricular septal defect were observed. Results A total of 100 VSD children presented with clinical symptoms of fast breathing, retraction of the chest, cough, cyanosis, fever, difficulty during feeding, cyanotic spell, chest pain, and edema at 65%, 62%, 54%, 52%, 54%, 29%, 9%, 11%, and 4%, respectively. Conclusion Early diagnosis is essential for effective medical care of diseases such as infective endocarditis (IE), which is present in some cases of VSD, and the avoidance of persistent pulmonary veno-occlusive disease (PVOD).

Long-term results following atrioventricular septal defect repair.

BACKGROUND: Atrioventricular septal defects (AVSD) represent 4-7% of congenital cardiac malformations. Definitive early repair is favored over prior pulmonary artery banding and delayed definitive repair in many centers. The aim of this study was to analyze long-term outcomes following AVSD repair over a 21-year period. METHODS: A total of 202 consecutive patients underwent surgical AVSD correction between June 1999 and December 2020. Surgery was performed using the double-patch technique. The study data were prospectively collected and retrospectively analyzed. Primary outcomes were In-hospital mortality and overall long-term freedom from reoperation. RESULTS: Median age at operation was 120 days (IQR 94-150), median weight was 5.0 kg (4.2-5.3). None of the patients died within the first 30 postoperative days. In-hospital mortality was 0.5% (1/202 patients). Median follow-up was 57 months (11-121). Overall freedom from reoperation at 5, 10 and 15 years was 91.8%, 86.9% and 86.9%, respectively. CONCLUSION: AVSD repair with the double-patch technique is a safe and effective procedure with good early postoperative outcomes and low long-term reoperation rates.

A comparative analysis on risk of pulmonary hypertension in children with Atrio-ventricular (AV) canal defect: a multi-centre study.

Objectives: This study is aimed at determining the risk of pulmonary hypertension in children with AV canal defect when compared with children with other congenital heart disease. Methods: A descriptive study carried out in three institutions over a six-year period among children who presented with AV canal defect and their controls who presented with other congenital heart defects. Results: A large proportion of the children with AV canal (77.5%) had pulmonary hypertension. Among the patients with pulmonary hypertension, 45.2% were males compared 54.8% females (χ2 = 3.2, p = 0.2). There was a positive correlation between pulmonary hypertension and size of VSD and ASD, although the correlation was not significant (Pearson correlation coefficient = 0.01 and 0.4, p = 0.9 and 0.1 respectively). Children with AV canal defect had higher odds of developing most clinical symptoms and pulmonary hypertension than children with other congenital heart disease and this is statistically significant. Conclusion: Majority of children with AV canal defect presented with pulmonary hypertension. These children present with higher odds of having pulmonary hypertension and clinical symptoms than children with other types of congenital heart disease.

Left ventricular hypoplasia: to septate or not?

When do we label a left ventricle as small? How is the decision made regarding suitability for a two-ventricle repair? Are dimensions the only criteria with which we decide, whether a ventricle will support the systemic circulation? Can we actually stimulate the growth of a borderline small left ventricle, so that it could support the systemic circulation in future? What role does mass and shape have to play in whether a borderline ventricle will support a biventricular repair? What role does the morphology and segmental anatomy play in this decision-making? This is a review article to address these issues.

Complete atrioventricular septal defect repair in Australia: Results over 25 years.

OBJECTIVES: To evaluate whether the long-term outcomes of modified-single-patch (MSP) repair of complete atrioventricular septal defect are equivalent to double-patch (DP) repair with respect to survival and risk of reoperation for left atrioventricular valve regurgitation or left ventricular outflow tract obstruction. METHODS: All patients who underwent biventricular repair of complete atrioventricular septal defect in Australia from 1990 to 2015 using either a MSP or DP technique were identified. Demographic characteristic details, operative data, and outcomes were analyzed. A propensity score analysis was performed to balance the 2 treatment groups according to several baseline covariates. Survival and freedom from reintervention between the 2 groups were compared using Kaplan-Meier curves and log-rank tests. RESULTS: A total of 819 patients underwent repair of complete atrioventricular septal defect (252 MSP and 567 DP) during the study period. There was no significant difference in unmatched survival (P = .85) and event-free survival (P = .49) between MSP and DP repair. Propensity score matching resulted in a total of 223 matched pairs. Matched analysis found no difference in overall survival (P = .59) or event-free survival (P = .90) between repair techniques, with an estimated event-free survival at 5, 10, and 15 years of 83%, 83%, and 74% for DP and 83%, 80%, and 77% for the MSP group, respectively. There was no significant difference between repair techniques in reoperation for left atrioventricular valve regurgitation or left ventricular outflow tract obstruction or need for permanent pacemaker. CONCLUSIONS: Overall and event free survival are similar following either MSP or DP repair of complete atrioventricular septal defect. There is no increased risk of reoperation for left ventricular outflow tract obstruction with the MSP technique.

Surgical Considerations in Atrioventricular Canal Defects.

Atrioventricular canal defects represent a diverse and challenging group of defects. Timing and surgical technique is greatly dependent on morphology of the valve as well as symptoms. Surgical options for repair of these defects are reviewed and presented below.

Utilizing the PCICS Nursing Guidelines in Managing the CICU Patient.

The Pediatric Cardiac Intensive Care Society (PCICS) Nursing Guidelines were developed to provide an evidence-based resource for bedside cardiac intensive care unit nursing care. Guideline topics include postoperative care, hemodynamic monitoring, arrhythmia management, and nutrition. These evidence-based care guidelines were presented at the 10th International Meeting of PCICS and have been utilized in the preparation of this article. They can be accessed at http://www.pcics.org/resources/pediatric-neonatal/. Utilization of these guidelines in practice is illustrated for single ventricle stage 1 palliation, Fontan operation, truncus arteriosus, and atrioventricular septal defect.

Two-ventricle repairs in the unbalanced atrioventricular canal defect spectrum with midterm follow-up.

OBJECTIVES: Unbalanced atrioventricular (AV) canal defects include a hypoplastic ventricle (HV) and AV valve (HAVV) precluding complete 2-ventricle repairs (2VRs). Catch-up growth would solve this problem and was induced by increasing HAVV flow. The objectives were to assess reliability of HV and HAVV growth and provide 5- to 15-year 2VR follow-up. METHODS: From 1990 to 2005, 23 consecutive infants (13 females and 10 males) with echo-diagnosed unbalanced AV canal defects (n = 20) or subsets (n = 3) underwent 2VRs. HV volumes (18 left and 5 right) and HAVV sizes estimated from biplane echoes and z values (standard deviation from expected) were determined. Hypoplasia was defined by a z value of less than -2.0. Three operative approaches were used: (1) Staged repairs (n = 9) had complete AVV repairs with partial atrial septal defect and ventricular septal defect closures, which increased HAVV flow and maintained stability. The septal defects were closed later. (2) An asymmetric valve partition (n = 8) was used to increase HAVV size. (3) For moderate hypoplasia, HAVV flow was increased and ASDs/VSDs were left for stability (n = 6). Follow-up at 5 to 19 years was done locally. RESULTS: Staged repairs began at 20 to 328 days (average, 129 days) and were completed 5 to 145 days later (average, 101 days). Midterm survival was 87% (20/23) after 1 central nervous system bleed after trial weaning from extracorporeal membrane oxygenation and 2 later deaths from hyperkalemia. Reoperations for AVV regurgitation (n = 3), AVV stenosis (n = 1), and mitral valve replacement (n = 1) were satisfactory. On follow-up, all hypoplastic structures (HV and HAVV) had grown to normal size. Two patients "doing well" were lost to follow-up. Survivors have satisfactory 2VRs, with 15 of 18 taking no cardiac failure medications. CONCLUSIONS: Reliable HV/HAVV catch-up growth was induced, and all midterm 2VRs were satisfactory.