Heart Development and Congenital Structural Heart Defects.

Congenital heart disease is the most frequent birth defect and the leading cause of death for the fetus and in the first year of life. The wide phenotypic diversity of congenital heart defects requires expert diagnosis and sophisticated repair surgery. Although these defects have been described since the seventeenth century, it was only in 2005 that a consensus international nomenclature was adopted, followed by an international classification in 2017 to help provide better management of patients. Advances in genetic engineering, imaging, and omics analyses have uncovered mechanisms of heart formation and malformation in animal models, but approximately 80% of congenital heart defects have an unknown genetic origin. Here, we summarize current knowledge of congenital structural heart defects, intertwining clinical and fundamental research perspectives, with the aim to foster interdisciplinary collaborations at the cutting edge of each field. We also discuss remaining challenges in better understanding congenital heart defects and providing benefits to patients.

Human Genetics of d-Transposition of Great Arteries.

Although several genes underlying occurrence of transposition of the great arteries have been found in the mouse, human genetics of the most frequent cyanotic congenital heart defect diagnosed in neonates is still largely unknown. Development of the outflow tract is a complex process which involves the major genes of cardiac development, acting on myocardial cells from the anterior second heart field, and on mesenchymal cells from endocardial cushions. These genes, coding for transcription factors, interact with each other, and their differential expression conditions the severity of the phenotype. A precise description of the anatomic phenotypes is mandatory to achieve a better comprehension of the complex mechanisms responsible for transposition of the great arteries.

Ventricular Septal Defects: Molecular Pathways and Animal Models.

Ventricular septation is a complex process which involves the major genes of cardiac development, acting on myocardial cells from first and second heart fields, and on mesenchymal cells from endocardial cushions. These genes, coding for transcription factors, interact with each other, and their differential expression conditions the severity of the phenotype. In this chapter, we will describe the formation of the ventricular septum in the normal heart, as well as the molecular mechanisms leading to the four main anatomic types of ventricular septal defects: outlet, inlet, muscular, and central perimembranous, resulting from failure of development of the different parts of the ventricular septum. Experiments on animal models, particularly transgenic mouse lines, have helped us to decipher the molecular determinants of ventricular septation. However, a precise description of the anatomic phenotypes found in these models is mandatory to achieve a better comprehension of the complex mechanisms responsible for the various types of VSDs.

Aorta Without Coronary Arteries: Anatomic Variants of a Rare Malformation.

Absence of connection of both coronary arteries to the aorta is an extremely rare congenital malformation. Most cases reported are anatomic variants of anomalous left coronary artery to pulmonary artery, found in isolation or in association with other congenital heart defects. We describe here four cases of patients born without any coronary artery connected to the aorta, including two with an almost complete absence of epicardial coronary arteries, one with single coronary artery to the right pulmonary artery, and one with left ventricular connection of a single coronary artery. Those exceptional coronary malformations have a poor prognosis and are often diagnosed at autopsy. Total absence of epicardial coronary arteries, present in two of our patients and described only once in the literature, leads us to reconsider current knowledge of human coronary artery development.

Inferior sinus venosus defect and anomalous hepatic venous return to the coronary sinus leading to an Eisenmenger syndrome.

Inferior sinus venosus defect associated with left hepatic vein drainage to the coronary sinus is an extremely rare condition. We report the case of a 41-year-old man suffering from pulmonary arterial hypertension related to this unusual CHD. Planning of heart-lung transplantation in this case required accurate anatomical description.

Acute Heart Failure in Multisystem Inflammatory Syndrome in Children in the Context of Global SARS-CoV-2 Pandemic.

BACKGROUND: Cardiac injury and myocarditis have been described in adults with coronavirus disease 2019 (COVID-19). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children is typically minimally symptomatic. We report a series of febrile pediatric patients with acute heart failure potentially associated with SARS-CoV-2 infection and the multisystem inflammatory syndrome in children as defined by the US Centers for Disease Control and Prevention. METHODS: Over a 2-month period, contemporary with the SARS-CoV-2 pandemic in France and Switzerland, we retrospectively collected clinical, biological, therapeutic, and early outcomes data in children who were admitted to pediatric intensive care units in 14 centers for cardiogenic shock, left ventricular dysfunction, and severe inflammatory state. RESULTS: Thirty-five children were identified and included in the study. Median age at admission was 10 years (range, 2-16 years). Comorbidities were present in 28%, including asthma and overweight. Gastrointestinal symptoms were prominent. Left ventricular ejection fraction was <30% in one-third; 80% required inotropic support with 28% treated with extracorporeal membrane oxygenation. Inflammation markers were suggestive of cytokine storm (interleukin-6 median, 135 pg/mL) and macrophage activation (D-dimer median, 5284 ng/mL). Mean BNP (B-type natriuretic peptide) was elevated (5743 pg/mL). Thirty-one of 35 patients (88%) tested positive for SARS-CoV-2 infection by polymerase chain reaction of nasopharyngeal swab or serology. All patients received intravenous immunoglobulin, with adjunctive steroid therapy used in one-third. Left ventricular function was restored in the 25 of 35 of those discharged from the intensive care unit. No patient died, and all patients treated with extracorporeal membrane oxygenation were successfully weaned. CONCLUSIONS: Children may experience an acute cardiac decompensation caused by severe inflammatory state after SARS-CoV-2 infection (multisystem inflammatory syndrome in children). Treatment with immunoglobulin appears to be associated with recovery of left ventricular systolic function.

Long-Term Neurodevelopmental Outcomes of Children with Congenital Heart Defects.

OBJECTIVE: To assess whether children with symptomatic congenital heart defects (CHDs) at birth (cyanosis and/or heart failure) are at greater risk of adverse neurodevelopmental outcomes at 8 years of age. STUDY DESIGN: From a prospective population-based cohort study of newborns with CHDs (EPICARD), we included 473 children with available neurodevelopmental assessments at 8 years of age. We grouped the CHD based on symptoms at birth and need for early neonatal intervention. Ventricular septal defects that closed spontaneously within the first year of life were considered the control group. Neurodevelopmental outcomes were assessed using the Kauffman Assessment Battery Test for Children, Second Edition, for IQ (mean 100 ± 15), and the Developmental NEuroPSYchological Assessment Battery, Second Edition, for detailed assessment of specific neurocognitive domains (mean 10 ± 3). Multivariable regression analysis was used to compare the outcomes across the CHD groups after considering potentially confounding variables. RESULTS: Compared with the control group, children with cyanotic CHD without heart failure had lower scores for IQ, -7.2 (95% CI -13.4 to -1.2). Children with noncyanotic CHD with heart failure had lower scores in the specific domains of language -1.5 (95% CI -2.2 to -0.7), and memory and learning -1.3 (95% CI -2.4; -0.3). Those with both cyanotic CHD and heart failure had lower scores for IQ, -7.6 (95% CI -13.5 to -1.8), as well as the specific domains of language and memory and learning, -2.0 (95% CI -2.9 to -1.0) and -1.1 (95% CI -2.3 to -0.1), respectively. CONCLUSIONS: Children with symptomatic CHD at birth are at greater risk of adverse neurodevelopmental outcomes at 8 years of age, with the greatest risk for those who were born with both cyanosis and heart failure.

Prenatal diagnosis of anomalous connection of the inferior caval vein to the left atrium associated with common arterial trunk.

Anomalous connection of the inferior caval vein to the left atrium is exceedingly rare, and has even been considered by some authors an anatomic and embryologic impossibility. This study demonstrates for the first time the existence of this rare malformation, diagnosed on prenatal echo, and confirmed on post-mortem examination in a 24 WG fetus, in association with a common arterial trunk.

Abnormal origin of the left pulmonary artery from the descending aorta and heterotaxy syndrome: an undescribed phenotypic association.

Extensive screening in a newborn with prenatal suspicion of VACTERL syndrome identified an anomalous origin of the left pulmonary artery from the descending aorta with an arterial duct and left aortic arch, and normal intra-cardiac anatomy. Other anatomical anomalies suggested heterotaxy syndrome. At one-month-old, re-implantation of the 3.5 mm left pulmonary artery was performed by direct tension-low anastomosis. Post-operative course was complicated by severe left pulmonary atelectasis, and the patient died 20 days later.

Heterotaxy: fluctuat nec mergitur.

The International Pediatric and Congenital Cardiac Code (IPCCC) states that visceral heterotaxy is defined as "a congenital malformation in which the internal thoraco-abdominal organs demonstrate abnormal arrangement across the left-right axis of the body. By convention, in congenital cardiology, heterotaxy syndrome does not include patients with complete mirror-imaged arrangement of the internal organs along the left-right axis also known as "total mirror imagery" or "situs inversus totalis"." [www.ipccc.net]In patients with heterotaxy, it is important to describe both the cardiac relations and the junctional connections of the cardiac segments, with documentation of the arrangement of the atrial appendages, the ventricular topology, the nature of the unions of the segments across the atrioventricular and the ventriculoarterial junctions, the infundibular morphologies, and the relationships of the arterial trunks in space. Particular attention is required for the venoatrial connections, since these are so often abnormal. The relationship and arrangement of the remaining thoraco-abdominal organs, including the lungs, the spleen, the liver, and the intestines, also must be described separately, because, although common patterns of association have been identified, there are frequent exceptions to these common patterns. Therefore, in patients with heterotaxy, it is important to describe each thoracic and abdominal organ independently.

Nomenclature for Pediatric and Congenital Cardiac Care: Unification of Clinical and Administrative Nomenclature - The 2021 International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Revision of the International Classification of Diseases (ICD-11).

Substantial progress has been made in the standardization of nomenclature for paediatric and congenital cardiac care. In 1936, Maude Abbott published her Atlas of Congenital Cardiac Disease, which was the first formal attempt to classify congenital heart disease. The International Paediatric and Congenital Cardiac Code (IPCCC) is now utilized worldwide and has most recently become the paediatric and congenital cardiac component of the Eleventh Revision of the International Classification of Diseases (ICD-11). The most recent publication of the IPCCC was in 2017. This manuscript provides an updated 2021 version of the IPCCC.The International Society for Nomenclature of Paediatric and Congenital Heart Disease (ISNPCHD), in collaboration with the World Health Organization (WHO), developed the paediatric and congenital cardiac nomenclature that is now within the eleventh version of the International Classification of Diseases (ICD-11). This unification of IPCCC and ICD-11 is the IPCCC ICD-11 Nomenclature and is the first time that the clinical nomenclature for paediatric and congenital cardiac care and the administrative nomenclature for paediatric and congenital cardiac care are harmonized. The resultant congenital cardiac component of ICD-11 was increased from 29 congenital cardiac codes in ICD-9 and 73 congenital cardiac codes in ICD-10 to 318 codes submitted by ISNPCHD through 2018 for incorporation into ICD-11. After these 318 terms were incorporated into ICD-11 in 2018, the WHO ICD-11 team added an additional 49 terms, some of which are acceptable legacy terms from ICD-10, while others provide greater granularity than the ISNPCHD thought was originally acceptable. Thus, the total number of paediatric and congenital cardiac terms in ICD-11 is 367. In this manuscript, we describe and review the terminology, hierarchy, and definitions of the IPCCC ICD-11 Nomenclature. This article, therefore, presents a global system of nomenclature for paediatric and congenital cardiac care that unifies clinical and administrative nomenclature.The members of ISNPCHD realize that the nomenclature published in this manuscript will continue to evolve. The version of the IPCCC that was published in 2017 has evolved and changed, and it is now replaced by this 2021 version. In the future, ISNPCHD will again publish updated versions of IPCCC, as IPCCC continues to evolve.

Congenitally corrected transposition of the great arteries: is it really a transposition? An anatomical study of the right ventricular septal surface.

Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital malformation which associates discordant atrioventricular and ventriculo-arterial connections. Although frequently associated with a ventricular septal defect (VSD), its anatomy remains controversial. This could be due in hearts with usual atrial arrangement to the apparently different anatomy of the left-sided right ventricle compared with a right-sided right ventricle. We wanted to compare the RV septal anatomy between ccTGA, transposition of the great arteries and normal heart and to determine the anatomy of the VSD in ccTGA. We analysed 102 human heart specimens: 31 ccTGA, 36 transpositions of the great arteries, 35 normal hearts. According to the last classification of VSD (ICD-11), VSD were classified as outlet if located above the superoseptal commissure of the tricuspid valve and inlet if underneath. We measured the lengths of the superior and inferior limbs of the septal band and the angle between the two limbs. To assess the orientation of the septal band, we also measured the angle between superior limb and the arterial valve above. A VSD was present in 26 ccTGA (84%) and was an outlet VSD in 16 cases (61%). The mean angle between the two limbs of the septal band was 76.4° for ccTGA compared with 90.6° for transposition of the great arteries (P = 0.011) and 76.1° for normal hearts (P= NS). The mean angle between the superior limb of the septal band and the arterial valve above was 70.6° for ccTGA compared with 90.6° for transposition of the great arteries (P = 0.0004) and 69.1° for normal hearts (P= NS). The inferior limb of the septal band was significantly shorter in ccTGA (P < 0.0003): SL/IL length ratio was 21.4 for ccTGA, 2.2 for transposition of the great arteries and 1.5 for normal hearts. The typical VSD in ccTGA is an outlet VSD. Its frequent misdiagnosis as an inlet VSD might be explained by the shortness of the inferior limb, which creates the illusion of a posterior VSD, and by the fact that the VSD is usually assessed from the left ventricular aspect. Surprisingly, the orientation of the septal band is similar in ccTGA and normal heart, despite the discordant atrioventricular connections, and different in ccTGA and transposition of the great arteries, despite the discordant ventriculo-arterial connections. These findings suggest that the mechanism leading to transposition in ccTGA and in TGA probably is different. The term 'double discordance' might therefore be more appropriate as a description of this complex anomaly.

A new anatomic approach of the ventricular septal defect in the interruption of the aortic arch.

The aim of this study was to analyse the anatomy of the ventricular septal defect (VSD) in heart specimens with interruption of the aortic arch (IAA) in order to explore the hypothesis of different embryologic mechanisms for the different anatomic types of IAA. We examined 42 human heart specimens, 25 with IAA as the main disease with concordant atrioventricular and ventriculo-arterial connections and two distinct great arteries, and 17 hearts with IAA associated with other malformations [six common arterial trunk (CAT), five double-outlet right ventricle (DORV), three transposition of the great arteries (TGA), three atrioventricular septal defect (AVSD)]. The interruption was classified according to Celoria and Patton. We focused on the anatomy of the VSD viewed from the right ventricular side. There were 15 IAA type A, 27 type B, no type C. The VSD in IAA type B was always an outlet VSD, located between the two limbs of the septal band, with posterior malalignment of the outlet septum in hearts with concordant ventriculo-arterial connections, without any fibrous tricuspid-aortic continuity. In addition, the aortic arch was always completely absent. Conversely, the VSD in IAA type A could be of any type (outlet in six, muscular in four, central perimembranous in two, inlet in three) and the aortic arch was either atretic or absent. In addition, IAA type B, when found in the setting of another anomaly, was always associated with neural crest-related anomalies (CAT and DORV), whereas IAA type A was found in association with anomalies not related to the neural crest (TGA and AVSD). These results reinforce the hypothesis that different pathogenic mechanisms are responsible for the two types of IAA, and the inclusion of IAA type B in the group of neural crest defects. Conversely, IAA type A could be due to overlapping mechanisms: flow-related defect (coarctation-like) and neural crest contribution.

Perinatal intracardiac teratoma: unusual presentation and review of the literature.

Intracardiac teratomas are rare primary tumours. We report the case of an infant prenatally diagnosed with an isolated multi-cystic mass developed in the right ventricle causing neonatal refractory ventricular arrhythmia. Despite rescue extracorporeal support and partial surgical resection, he died as almost all the previous reported perinatal intracardiac teratomas whatever the prenatal tolerance and the size of the tumour. The common poor outcome of fetal intracardiac teratomas should be known when counselling parents during pregnancy.

Merged bilateral arterial duct and circumflex retroesophageal right aortic arch in a fetus with normal intracardiac anatomy.

We report the case of a fetus with anamnios sequence and VACTERL syndrome, having a circumflex right aortic arch. Two arterial ducts join anteriorly to form a common vessel that connects to the pulmonary trunk with confluent pulmonary branches. Embryologically, the dorsal right 6th aortic arch did not disappear and the aortic arch development stopped in a symmetrical state with an exceptional "Y-shaped" merged bilateral arterial duct.

Impact of preterm birth on infant mortality for newborns with congenital heart defects: The EPICARD population-based cohort study.

BACKGROUND: Congenital heart defects (CHD) and preterm birth (PTB) are major causes of infant mortality. However, limited data exist on risk of mortality associated with PTB for newborns with CHD. Our objective was to assess impact of PTB on risk of infant mortality for newborns with CHD, while taking into account the role of associated anomalies and other potentially confounding factors. METHODS: We used data on 2172 live births from a prospective population-based cohort study of CHD (the EPICARD Study) and compared neonatal, post-neonatal and overall infant mortality for infants born at <32, 32-34 and 35-36 weeks vs. those born at term (37-41 weeks). RESULTS: Preterm newborns had a 3.8-fold higher risk of infant death (17.9%) than term newborns (4.7%), RR 3.8, 95%CI 2.7-5.2; the risk associated with PTB was more than four-fold higher for neonatal (RR 4.3, 95% CI 2.9-6.6) and three-fold higher for post-neonatal deaths (RR 3.0, 95% CI 1.7-5.2). Survival analysis showed that newborns <35 weeks had a higher risk of mortality, which decreased but persisted after exclusion of associated anomalies and adjustment for potential confounders. CONCLUSIONS: Preterm birth is associated with an approximately four-fold higher risk of infant mortality for newborns with CHD. This excess risk appears to be mostly limited to newborns <35 weeks of gestation and is disproportionately due to early deaths.

Temporal trends and changing profile of adults with congenital heart disease undergoing heart transplantation.

AIMS: To investigate the temporal trends in profile and outcomes of adults with congenital heart disease (ACHD) undergoing heart transplantation (HT). METHODS AND RESULTS: Out of a multi-institutional series of 2257 HT from 1988 to 2012, 100 HT were performed in 97 ACHD. We evaluated clinical characteristics, underlying defect, surgical history, perioperative issues, and outcomes. We compared two eras: era 1 (1988-2005, n = 48) and era 2 (2006-2012, n = 49). Mean age at HT was 30.3 ± 10.5 years. Twenty-five patients (25.8%) had biventricular physiology with a systemic right ventricle and 43 patients (44%) had univentricular physiology. Adults with congenital heart disease severity were classified as great complexity (74.2%), moderate (21.7%), and simple (4.1%). During a median follow-up of 28.7 months [0-282], 44 patients died. Early mortality was high (34%; 95% CI 0.2536-0.4390). Survival was 63.9% at 1 year. The proportion of univentricular patients did not change. Biventricular patients with systemic right ventricle significantly increased in era 2 (16.7  vs. 34.7%, P = 0.04) due to increasing number of transposition of the great arteries with atrial switch. Although the proportion of great complexity ACHD did not change significantly in era 2 (81.6%  vs. and 66.7% in era 1, P = 0.09), ACHD recipients have more advanced disease, being more likely hospitalized (P = 0.03), receiving intravenous inotropes (P = 0.01), under assist devices (P = 0.04), or UNOS status 1 (P = 0.02) at the time of HT. Survival rates were comparable. CONCLUSION: Despite a worse risk profile, mortality after HT in ACHD did not increase. Improving survival of complex CHD will probably amplify the proportion of complex ACHD recipients with more advanced disease.

Antenatal diagnosis of double-outlet left atrium.

In this study, we describe a fetus with double-outlet atrium associated with complex arrangement of the ventricles and the great vessels. Various presentations of this malformation not described antenatally are discussed.

Nomenclature for congenital and paediatric cardiac disease: the International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Iteration of the International Classification of Diseases (ICD-11).

An internationally approved and globally used classification scheme for the diagnosis of CHD has long been sought. The International Paediatric and Congenital Cardiac Code (IPCCC), which was produced and has been maintained by the International Society for Nomenclature of Paediatric and Congenital Heart Disease (the International Nomenclature Society), is used widely, but has spawned many "short list" versions that differ in content depending on the user. Thus, efforts to have a uniform identification of patients with CHD using a single up-to-date and coordinated nomenclature system continue to be thwarted, even if a common nomenclature has been used as a basis for composing various "short lists". In an attempt to solve this problem, the International Nomenclature Society has linked its efforts with those of the World Health Organization to obtain a globally accepted nomenclature tree for CHD within the 11th iteration of the International Classification of Diseases (ICD-11). The International Nomenclature Society has submitted a hierarchical nomenclature tree for CHD to the World Health Organization that is expected to serve increasingly as the "short list" for all communities interested in coding for congenital cardiology. This article reviews the history of the International Classification of Diseases and of the IPCCC, and outlines the process used in developing the ICD-11 congenital cardiac disease diagnostic list and the definitions for each term on the list. An overview of the content of the congenital heart anomaly section of the Foundation Component of ICD-11, published herein in its entirety, is also included. Future plans for the International Nomenclature Society include linking again with the World Health Organization to tackle procedural nomenclature as it relates to cardiac malformations. By doing so, the Society will continue its role in standardising nomenclature for CHD across the globe, thereby promoting research and better outcomes for fetuses, children, and adults with congenital heart anomalies.