The incidence of congenital heart defects is approximately 8 in 1000 births.1 Over the course of the past decades survival of children with congenital heart disease (CHD) has improved. Today, adults frequently present for routine general surgery and obstetric care after having had various congenital cardiac surgical repairs in childhood. Unfortunately, the frequently multistaged surgical repairs necessary to improve survival in children often result in complex cardiac physiology in adulthood. Knowledge of the anatomy of the original structural defect and the repairs undertaken is essential in the choice of appropriate monitoring and anesthetic techniques for otherwise routine procedures. Moreover, CHD patients may require additional heart surgery and/or cardiac transplantation later in life. For children with CHD identification of those patients at highest risk for anesthesia complications is critical. Such children include those with a functional single ventricle, children with suprasystemic pulmonary hypertension, children with left ventricular outflow tract obstruction, and lastly patients with dilated cardiomyopathy.2 This chapter highlights the anatomy, physiology, and correction of common congenital heart defects. In general, surgical repairs are directed at ensuring the delivery of oxygenated blood to the systemic tissues and eliminating communications between the right and left heart. Of course, for some CHD patients the distinction of which is the right heart and which is the left heart may not be entirely clear. Consequently, when considering the CHD patient, tracing the flow of blood through the chambers of the heart into the circulation and back again provides the basis toward acquiring an understanding of CHD.
Atrial septal defects (ASDs) are abnormal communications between the left atrium (LA) and right atrium (RA). A patent foramen ovale (PFO) may be present in up to 25% of the population and produces a small interatrial communication as a consequence of failure of the septum primum and septum secundum to fuse. ASDs account for 6% to 10% of the CHD population and present in a variety of ways.3 Eighty percent of ASDs are of the ostium secundum type (Figure 12–1 and Videos 12–1A and 12–1B) located in the middle of the interatrial septum. Defects located lower in the atrial septum [toward the atrial-ventricular (AV) valves] are ostium primum ASDs and are at times associated with a ventricular septal defect (VSD) (Figure 12–2). Sinus venosus ASDs occur close to the junctions of the superior vena cava (SVC) or inferior vena cava (IVC) with the RA (Figure 12–3). Sinus venosus ASDs are often associated with pulmonary vein anomalies and anomalous return of oxygenated pulmonary vein blood to the right atrium.
Video 12–1A: Secundum Atrial Septal Defect
Video 12–1B: Primum Atrial Septal Defect: Color Flow Doppler
An ostium secundum atrial septal defect (ASD) is ...