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.

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 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.

OBJECTIVE: 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.