What are the causes of an enlarged heart?

Causes of an enlarged heart are usually high blood pressure or coronary artery disease, according to WebMD. Other causes include a viral infection of the heart, alcohol or cocaine abuse, genetics, and an abnormal heart valve.

High blood pressure tends to cause enlargement of the left ventricle, while hypertrophic cardiomyopathy is genetic, states WebMD. Coronary artery disease blocks the blood supply of the heart, causing it to enlarge to keep pumping blood. However, pumping capabilities decline as the heart becomes larger. People with enlarged hearts may show no symptoms whatsoever, mild, static symptoms, or gradually declining shortness of breath and other signs of congestive heart failure.