Cardiac Axis in Early Gestation and Congenital Heart Disease

Fig. (1). Flowchart of the search results.

Fig. (2). Four-chamber view of the fetal heart. Schematic drawing of a cross-section of the thorax at the level of the four-chamber view with an arrow tracing the long axis of the heart. Normal cardiac axis (characterized by a leftward deviation of the cardiac axis by approximately 45° from the midline, with a range of variation of plus or minus 10-20°) (a). Three distinct types of cardiac axis abnormalities: dextrocardia (the major axis of the heart is oriented to the right) (b); mesocardia (the longitudinal axis of the heart situated in the mid-sagittal plane) (c); and severe levocardia (leftward deviation of the cardiac axis beyond the angle previously mentioned) (d). LA, left atrium; RA, right atrium; LV, left ventricle; RV, right ventricle; Ao, aorta; L, left; R, right.

Fig. (3). Cardiac axis measurement obtained in a fetus at 11 + 6 weeks of gestation. Cross-section of the thorax at the level of the four-chamber view demonstrating the normal cardiac axis. When the image of the chest can be obtained at this level, the cardiac axis can be measured as the angle between the line that bisects the thorax in the anteroposterior direction and the line tracing the heart's long axis. It can be noticed, in this image, the leftward deviation of the cardiac axis by approximately 48.45°.