The Examination of the Normal Fetal Heart

The heart, anatomically and embryologically, is a segmented structure. The atria, the ventricles and the great arteries are the three major fundamental components. The heart should be examined echocardiographically by Sequential Segmental Analysis from the venous to the arterial poles following the blood flow. Each segment is evaluated independently considering not only the segmental situs (or location into the body) but also the connections of each heart segment to the others. A systematic approach by Sequential Segmental Analysis is a cornerstone of fetal cardiac study. First step is the identification of fetal heart position followed by the identification of position of the heart in relation to the body and the anatomic study of each cardiac chamber, and finally, the study of cardiac rhythms and function. The heart can be observed in infinity of planes, but few sections are the basis of fetal cardiac study. The examination starts with abdominal cross-sectional view for the identification of the viscero-atrial situs. Then the transthoracic four-chamber view should be obtained. This view allows to obtains a large amount of informations specially regarding the atria and ventricles, atrioventricular valves, interatrial and interventricular septum. Ventriculo-arterial connections are well identified by a gentle sweep towards the fetal neck, left ventricular outflow tract and ascending aorta are first visualized and, by further sweeping, also right ventricular outflow tract, branch pulmonary arteries and ductus arteriosus are correctly identified. The three vessel view give us information regarding left or right location of aortic arch. Short axis of the heart is evaluated from the cavo-atrial and ventricular segments to the ductal and aortic arches. Finally the study of heart rate and rhythm and of myocardial function ends the fetal heart examination.

Keywords: Fetal Heart, Ultrasound, Diagnostic Planes, Segmental Analysis