Congenital Heart Disease Glossary

arteriohepatic dysplasia

An autosomal dominant multi-system syndrome consisting of intrahepatic cholestasis, characteristic facies, butterfly-like vertebral anomalies and varying degrees of peripheral pulmonary artery stenoses or diffuse hypoplasia of the pulmonary artery and its branches. Associated with microdeletion in chromosome 20p. syn. Alagille syndrome.

asplenia syndrome

see right isomerism.

atresia, atretic

Imperforate, used with reference to an orifice, valve, or vessel.

atrial septal defect (ASD)

an inter-atrial communication, classified according to its location relative to the oval fossa (fossa ovalis):

atrial switch procedure

A procedure to redirect venous return to the contralateral ventricle. When used in complete transposition of the great arteries (either the Mustard or the Senning procedure) this accomplishes physiologic correction of the circulation, while leaving the right ventricle to support the systemic circulation. In patients with l-transposition of the great arteries and in patients who have had a previous Mustard or Senning procedure, it is used as part of a "double switch procedure" which results in anatomic correction of the circulation, with the left ventricle supporting the systemic circulation. see also double switch procedure.

atrio-ventricular concordance

see concordant atrio-ventricular connections.

atrio-ventricular discordance

see discordant atrio-ventricular connections.

atrio-ventricular septal defect (AVSD)

A group of anomalies resulting from a deficiency of the atrio-ventricular septum which have in common: 1) a common atrio-ventricular junction with a common fibrous ring, and a unique, 5-leaflet, atrio-ventricular valve; 2) unwedging of the aorta from its usual position deeply wedged between the mitral and tricuspid valves; 3) a narrowed subaortic outflow tract; 4) disproportion between the inlet and outlet portions of the ventricular septum. Echocardiographic recognition is aided by the observation that "left" and "right" A-V valves are located in the same anatomic plane. Included in this group of conditions are anomalies previously known as (and often still described as) ostium primum ASD (partial AVSD), "cleft" anterior mitral and/or septal tricuspid valve leaflet, inlet VSD, and complete AVSD ("complete A-V canal defect"). An older, obsolete, term describing such a defect is "endocardial cushion defect". see also endocardial cushion defect.

atrio-ventricular septum

The atrio-ventricular septum separates the left ventricular inlet from the right atrium. It has two parts: a muscular portion which exists because the attachment of the septal leaflet of the tricuspid valve is more towards the apex of the ventricle than the corresponding attachment of the mitral valve, and a fibrous portion superior to the attachment of the septal leaflet of the tricuspid valve. This latter portion separates the right atrium from the sub-aortic left ventricular outflow tract. see also Gerbode defect.

atrio-ventricular valve (A-V valve)

A valve guarding the inlet to a ventricle. A-V valves correspond with their respective ventricles, the tricuspid valve always associated with the right ventricle, and the mitral valve with the left ventricle. However, in the setting of an atrio-ventricular septal defect, there is neither a true mitral nor a true tricuspid valve. Rather, in severe forms there is a single atrio-ventricular orifice, guarded by a 5-leaflet A-V valve. The "left A-V valve" comprises the left lateral leaflet and the left portions of the superior (anterior) and inferior (posterior) bridging leaflets, while the "right A-V valve" comprises the right inferior leaflet, the right antero-superior leaflet, and the right portions of the superior and inferior bridging leaflets.