The radiologic features of cardiac rotation: a pictorial essay.

Rotation of the heart results from enlargement of individual cardiac chambers and influences significantly the configuration of the cardiomediastinal silhouette. Left ventricular enlargement leads to dextrorotation. Conversely, right ventricular enlargement leads to levorotation. The axis of rotation is nearly vertical and extends from the top of the aortic arch through the anterior wall of the left atrium and the proximal interventricular septum. Pericardial defect, deformity of the thoracic skeleton, and lower lobe atelectasis can also lead to cardiac rotation. An understanding of this concept facilitates the interpretation of chest radiographs in patients with heart disease. The terms clockwise and counterclockwise rotation of the heart should be abandoned.