Anomalies of the Atrial Septum

Defects that allow interatrial communication can result from openings in the atrial septum, or from defects in the sinus venosus component of the atria, or in the tissue that separates the coronary sinus from the left atrium. A patent foramen ovale is an interatrial communication that exists normally in the fetus and in most newborns, but because of its clinical importance in certain congenital heart defects and in older patients with paradoxical emboli and stroke, it is discussed in this chapter. Atrial septal defects are further classified into secundum and primum defects. The atrial septum is imaged from multiple acoustic windows, including the subxiphoid, apical, left parasternal, and high right parasternal. Two- and three-dimensional imaging as well as color and spectral Doppler techniques are used in concert for comprehensive evaluation of the fossa ovalis, sinus venosus, and coronary sinus.