Ventricular and atrial septal defects.

Abstract

1. Nancy L. McDaniel, MD* 1. 2. *Department of Pediatrics, Division of Cardiology, University of Virginia, Charlottesville, VA. Objectives After completing this article, readers should be able to: 1. Review the anatomy of ventricular septal defect (VSD) and atrial septal defect (ASD). 2. Describe the clinical variables in children who have VSD and ASD. 3. Delineate the evaluation of VSD and ASD. 4. Describe the rationale for medical or surgical management of VSD and ASD. Congenital heart defects affect slightly less than 1% of liveborn infants. Two defects, ventricular septal defect (VSD) and atrial septal defect (ASD), account for about 30% of congenital heart disease: VSD for 20% and ASD for 10%. These defects may occur as isolated lesions or as a component of complex defects. This article focuses on the isolated defects. Most children who have either VSD or ASD are diagnosed rapidly and will have normal life expectancy. VSDs are defined by location and size. Each characteristic determines, in part, the pathophysiology and need for therapy. ### Definition VSDs are described by the anatomic location of the defect as seen from the right ventricle. The most common types are perimembranous, outlet, inlet, and muscular. Perimembranous VSDs (70% of all VSDs) are located in the upper fibrous region of the septum beneath the septal leaflet of the tricuspid valve and usually represent a single defect. Outlet VSDs (5% of all VSDs) are found between the left and right ventricular outflow tracts just above the parietal and septal bands and just below the pulmonary valve. They usually are single defects. Inlet VSDs (5% of all VSDs) are seen in the posterior portion of the ventricular septum beneath or behind the tricuspid valve and typically are single defects. Muscular VSDs (20% of all VSDs) are located in the muscular wall between the left and right ventricles in any portion of the septum, although the most common locations are at the apex, at the anterior portion …