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Less frequent structural congenital cardiac anomalies include the following:
Single ventricle spectrum:
These anomalies include any complex lesion with only one functional ventricle and include hypoplastic right ventricle (RV) and left ventricle (LV) and, less commonly, a true undifferentiated single ventricular chamber. Surgical management involves ensuring adequate pulmonary blood flow via a systemic-to-pulmonary artery anastomosis (eg, modified Blalock-Taussig shunt [see Congenital Cardiovascular Anomalies: Definitive management]) for patients with decreased pulmonary blood flow or protecting the pulmonary vascular bed via pulmonary artery banding if pulmonary overcirculation exists. Later, the Fontan procedure (see Congenital Cardiovascular Anomalies: Treatment) can be used as definitive treatment to make the functioning single ventricle solely a systemic ventricle.
Pulmonary atresia with intact septum:
This anomaly is most frequently associated with a hypoplastic RV and follows the same treatment algorithm as tricuspid atresia (see Congenital Cardiovascular Anomalies: Tricuspid Atresia).
Double outlet right ventricle:
This anomaly is associated with a very wide spectrum of anatomy and physiology depending on the size and location of the ventricular septal defect (VSD), as well as the presence and degree of pulmonic stenosis. In the most common variety with a subaortic VSD, a complete repair is possible with closure of the VSD in such a way as to direct LV outflow to the aorta.
Ebstein's anomaly:
This anomaly consists of variable apical displacement and dysplasia of the septal and inferior leaflets of the tricuspid valve with dysplasia, but normal origin, of the anterior leaflet as well. These abnormalities displace the effective valve orifice downward, resulting in compromise of the function of the RV with an atrialized portion that is proximal to the valve opening. This anomaly has been associated with maternal use of lithium during pregnancy. Associated abnormalities include atrial septal defect, pulmonic stenosis, and Wolff-Parkinson-White syndrome.
There is a remarkably wide spectrum of presentation, ranging from severely cyanotic newborns to cardiomegaly with mild cyanosis in childhood to a previously asymptomatic adult presenting with atrial arrhythmias or reentry supraventricular tachycardia. The onset of symptoms depends on the degree of tricuspid valve anatomic and functional derangement and presence of accessory pathways (eg, Wolff-Parkinson-White syndrome). When symptoms result from a severely dysfunctional tricuspid valve, surgical repair or replacement should be considered.
Congenitally corrected transposition:
This anomaly is relatively rare and accounts for about 0.5% of congenital cardiac anomalies. The normal embryologic looping of the fetal heart tube is reversed, resulting in atrioventricular and ventriculoarterial discordance. The result is the right atrium connects to a right-sided morphologic LV and the left atrium connects to a left-sided morphologic RV. In almost all cases, the morphologic LV connects to the pulmonary artery and the morphologic RV connects to the aorta. The circulation is thus physiologically “corrected,” but associated anomalies are invariably present, including VSD, pulmonic stenosis, Ebstein's anomaly of the tricuspid valve, congenital atrioventricular block, mesocardia or dextrocardia, and heterotaxy syndromes. These anomalies result in a wide range of clinical manifestations. As patients reach adulthood, a common concern is the development of dysfunction of the morphologic RV, which serves as the systemic ventricle. This dysfunction may be subclinical or manifest as severe cardiomyopathy and heart failure, leading to consideration of heart transplantation.
Rare nonstructural cardiac anomalies include
See Arrhythmias and Conduction Disorders: Long QT Syndrome and Torsades de Pointes Ventricular Tachycardia for prolonged QT syndrome and other genetic arrhythmia syndromes with risks of severe and possibly fatal ventricular arrhythmias.
Last full review/revision March 2010 by Lee B. Beerman, MD
Content last modified July 2012
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