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.

Tricuspid atresia (TA) is a rare congenital heart condition that presents with a complete absence of the right atrioventricular valve. Because of the rarity of familial and/or isolated cases of TA, little is known about the potential genetic abnormalities contributing to this condition. Potential responsible chromosomal abnormalities were identified in exploratory studies and include deletions in 22q11, 4q31, 8p23, and 3p as well as trisomies 13 and 18. In parallel, potential culprit genes include the ZFPM2, HEY2, NFATC1, NKX2-5, MYH6, and KLF13 genes. The aim of this chapter is to expose the genetic components that are potentially involved in the pathogenesis of TA in humans. The large variability in phenotypes and genotypes among cases of TA suggests a genetic network that involves many components yet to be unraveled.

Although the terms \"single ventricle\" and \"univentricular heart\" are frequently used to describe a variety of complex congenital heart defects, in fact, nearly all hearts have two ventricles, although one of the two may be too small to be functional. A better term for these hearts would therefore be \"functional single ventricle.\"

Tricuspid atresia, a critical congenital heart defect (CHD), accounts for approximately 1% of all cases of CHDs. When tricuspid atresia is coupled with numerous other unexpected congenital cardiac anomalies, a patient\'s condition becomes more serious and more complex. We present a case that demonstrates the stepwise approach to the holistic treatment of congenital tricuspid atresia in the presence of normally related great vessels, a large ventricular septal defect (VSD), atrial septal defect (ASD), and trivial patent ductus arteriosus (PDA). While expanding upon the implementation of chest X-ray imaging, serial transthoracic echocardiogram (TTE) imaging, and the balloon atrial septostomy (BAS) procedure, we also provide insight into the multidisciplinary team-based approach utilized for this patient\'s case. This case illustrates a rare critical CHD coupled with other, more common congenital anomalies, and suggests that with multidisciplinary management and treatment, it is possible the mortality rates associated with this diagnosis could decline.

Encephaloceles and severe cardiac malformations are rare presentations in a newborn. The mechanism of these congenital abnormalities is relatively unknown, but it is hypothesized to be related to genetic, environmental, and maternal risk factors. This case report describes a newborn with an occipital encephalocele associated with severe right ventricular hypoplasia secondary to tricuspid and pulmonary atresia. The patient\'s maternal risk factors included obesity, type 2 diabetes mellitus, and everyday tobacco use during pregnancy. Education on preconception planning, management, and counseling is essential as a preventative measure in fetal development and is further emphasized in this case.

[This corrects the article DOI: 10.3389/fped.2023.1159342.].

The necropsy of a 2-day-old Noma horse that died of weakness showed an enlarged cardiac base and a narrow cardiac apex, suggesting cardiac malformation. The excised heart underwent imaging to investigate its luminal structure. On three-dimensional magnetic resonance imaging, the right atrium and right ventricle were discontinuous. The right atrium communicated with the left atrium and the left ventricle communicated with the right ventricle. The lumen narrowed near the pulmonary artery valve. Since the same findings were observed on gross examination, the foal was diagnosed with tricuspid atresia with ventricular and atrial septal defects, along with subvalvular pulmonic stenosis.

OBJECTIVE: In this study, we aimed to compare infants with univentricular hearts who underwent an initial ductus stenting to those receiving a surgical systemic-to-pulmonary shunt (SPS).
METHODS: All infants with univentricular heart and ductal-dependent pulmonary blood flow who underwent initial palliation with either a ductus stenting or a surgical SPS between 2009 and 2022 were reviewed. Outcomes were compared after ductus stenting or SPS including survival, probability of re-interventions and the probability to reach stage II palliations.
RESULTS: A total of 130 patients were evaluated, including 49 ductus stenting and 81 SPSs. The most frequent primary diagnosis was tricuspid atresia in 27, followed by pulmonary atresia with intact ventricular septum in 19 patients. There was comparable hospital mortality (2.0% stent vs 3.7% surgery, P = 0.91) between the groups, but shorter intensive care unit stay (median 1 vs 7 days, P < 0.01) and shorter hospital stay (median 7 vs 17 days, P < 0.01) were observed in patients with initial ductus stenting, compared to those with SPS. However, acute procedure-related complications were more frequently observed in patients with ductus stenting, compared with those with SPS (20.4 vs 6.2%, P = 0.01), and 10 patients needed a shunt procedure after the initial ductus stent. The cumulative incidence of reaching stage II was similar between ductus stenting and SPS (88.0 vs 90.6% at 12 months, P = 0.735). Pulmonary artery (PA) index (median 194 vs 219 mm2/m2, P = 0.93) at stage II was similar between patients with ductus stenting and SPS. However, the ratio of the left to the right PA index [0.69 (0.45-0.95) vs 0.86 (0.51-0.84), P = 0.015] was higher in patients who reached stage II with surgical shunt physiology, compared with patients with ductus stent physiology.
CONCLUSIONS: After initial ductus stenting in infants with univentricular heart, survival is comparable and post-procedural recovery shorter, but more acute stent dysfunctions and lower development of left PA are observed, compared to acute shunt dysfunctions. The less invasive procedure and shorter hospital stay are at the expense of more stent reinterventions.

A 45-days-old mixed-breed female cat was referred to a veterinary specialty hospital for evaluation due to poor general condition, dyspnea of possible cardiac origin, and a heart murmur. The results of the physical examination, thoracic radiography, and echocardiography led to a diagnosis of hypotrophy of the right ventricle, tricuspid atresia, and atrial septal defect. Cardiovascular pathological findings confirmed the clinical diagnosis in addition to the observation of a ventricular septal defect. To the authors\' knowledge, this is the first report of tricuspid atresia with atrial septal defect and ventricular septal defect in a cat.

Background: This study aims to evaluate clinical outcomes and hemodynamic variables late after the Björk procedure, regarding the pulmonary flow pattern. Methods: Patients who survived more than 15 years after the Björk procedure were included and then divided into two groups according to their pulmonary flow pattern by pulsed-wave Doppler assessment of echocardiography: patients with pulsatile systolic pulmonary flow (Group P) and those without (Group N). Results: A total of 43 patients were identified, of whom 13 patients were divided into Group P and 30 in Group N. Median age at the Björk procedure was 5.7 (2.1-7.3) years, and median follow-up was 32 (28-36) years. Survival after 15 years was higher in Group P, compared with Group N (100% vs 76% at 30 years, P = .045). Cardiac catheterization data demonstrated higher cardiac index in Group P patients compared with Group N patients (3.5 vs 2.8 L/m2, P = .014). Cardiac magnetic resonance imaging study revealed that Group P patients had higher right ventricular end-diastolic volume index (96 vs 57 mL/m2, P = .005), higher end-systolic volume index (49 vs 30 mL/m2, P = .013) and higher right ventricular stroke volume index (48 vs 25 mL/m2, P < .001), compared with Group N patients. Exercise capacity tests demonstrated that Group P patients showed a higher percent predicted peak oxygen consumption, compared with Group N patients (73 vs 58%, P < .001). Conclusions: Late after the Björk procedure, patients with a pulsatile systolic pulmonary flow had a larger right ventricle and better exercise capacity compared with those without pulsatile systolic pulmonary flow.