Atrial Septal Defects in the Adult

Patients with isolated atrial septal defects (ASDs) have benefited from important recent advances in the diagnosis, evaluation, and management of their conditions. This review will focus on adolescent and adult patients with sizeable ASDs who do not have other major associated cardiac defects.There are 3 major types of ASDs or interatrial communications: ostium secundum, ostium primum, and sinus venosus (Figure 1A) defects. The ostium secundum is a true defect of the atrial septum and involves the region of the fossa ovalis. The ostium primum defect is within the spectrum of the atrioventricular (AV) septal defects (Figure 1B; also known as AV canal defects or endocardial cushion defects), the complete form of which also includes a large ventricular septal defect and a common AV valve. The sinus venosus defect is usually located at the junction of the right atrium and superior vena cava and is almost always associated with partial anomalous pulmonary venous return. Two very uncommon types of ASDs may be mentioned briefly: the inferior vena cava form of the sinus venosus defect and the coronary sinus septal defect (in which a defect between the coronary sinus and the left atrium allows a left-to-right shunt to occur through an “unroofed” coronary sinus). Figure 1. A, A indicates superior sinus venosus ASD; B, secundum ASD; C, inferior sinus venosus ASD; D, ostium primum ASD or partial AV septal defect; E, secundum ASD without posterior septal rim; F, coronary sinus ASD; and IVC, inferior vena cava. B, AV junction viewed from the atrial aspect. Normal indicates normal heart; complete AVSD, complete AV septal defect with a common AV junction and a common, single AV valve, guarded by 5 leaflets (counterclockwise: superior bridging, left mural, inferior bridging, right inferior, and right anterosuperior); partial AVSD, partial AVSD or primum ASD with …