Four-chamber views of the heart

Abstract

Prenatal ultrasound is indispensable for the identification of congenital heart disease. The initial evaluation of the fetal heart is based on the appearance of the four-chamber view. The only way to critically evaluate the fetal heart is through a systematic approach. From an evaluation of the four-chamber view, much information can be obtained for diagnosing, and screening for, congenital heart disease. Assessing situs and counting the number of chambers begins the evaluation. In the fetal chest, the position and size of the heart from the four-chamber view should be assessed, and when abnormal, can be associated with cardiac and extracardiac anomalies. The axis of the heart is typically leftward at a forty-five degree angle from the midline. A deviation, especially a levorotation, is highly associated with congenital heart disease. The specific evaluation of the four-chamber view includes a detailed evaluation of the atria, ventricles, atrioventricular valves, and evaluation of the endocardium, myocardium, and pericardium. Many fetuses with congenital heart disease have abnormalities of the four-chamber view. Although still images may demonstrate congenital heart disease, this does not replace real-time evaluation. During real-time evaluation, arrhythmias, which are associated with an increased risk for congenital heart disease, are more likely to be identified. Furthermore, real-time evaluation allows evaluation of the contractility and the excursion of the atrioventricular valves. Abnormalities of the four-chamber view must prompt further evaluation for the presence of congenital heart disease. Four-chamber screening should be part of the sonographic evaluation of all fetuses in the second and third trimesters.