Levocardia

In levocardia, the heart is predominantly in the left hemithorax with a leftward apex. In dextrocardia, the heart is predominantly in the right hemithorax. Primary dextrocardia is defined as a condition in which the heart is in the right hemithorax due to a structural congenital heart defect. In primary dextrocardia the apex usually points to the right. Secondary dextrocardia is a condition in which the heart is either “pushed” or “pulled” toward the right hemithorax as a result of extracardiac abnormalities. Examples of conditions in which the heart is pushed toward the right hemithorax include left-sided tension pneumothorax, left congenital lobar emphysema, and left-sided diaphragmatic hernia. Conditions in which the heart is pulled toward the right hemithorax include hypoplasia and agenesis of the right lung. In secondary dextrocardia, the cardiac apex may point to the left or anteriorly. In mesocardia, the heart is midline and the apex typically points anteriorly or inferiorly.