A to Z: Endocardial Cushion Defect

May also be called: ECD; Atrioventricular Canal Defect; Atrioventricular Septal Defect; AVSD

An endocardial (en-doh-CAR-dee-ul) cushion defect is a congenital (present at birth) abnormal heart condition.

More to Know

The heart consists of four chambers — the left atrium and left ventricle and the right atrium and right ventricle. The chambers are separated by a wall of tissue called the septum. Two valves — the mitral and tricuspid valves — separate the atria (plural of atrium) from the ventricles.

With endocardial cushion defects, the tissues that form the septum don't grow completely while a baby is in the womb, leaving one or more holes between the atria or the ventricles. And in some cases, instead of two separate valves, there is only one large common valve, which may be malformed. The causes of endocardial cushion defects, commonly seen in children with Down syndrome, aren't fully understood.

Endocardial cushion defects can make the heart work harder to pump blood and cause symptoms such as difficulty feeding, failure to gain weight, lung congestion, and a bluish tint to the lips and fingernails (called cyanosis). Defects are usually corrected through surgery while the child is still an infant.

Keep in Mind

If left untreated, an endocardial heart defect can cause heart failure and may be life threatening. Once surgery has corrected a defect, however, most kids can lead a normal life with no restrictions on their activities.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.