Overview of Congenital Heart Defects

A congenital heart defect is a problem with the structure of the heart. Congenital heart defects, which are present at or before birth, are the most common type of major birth defect.

Anatomy of the Heart

The heart is a hollow, muscular, complex organ that pumps blood throughout the body. It includes four separate chambers, four valves, and an electrical impulse system that work together to receive and distribute blood in a highly organized manner. The heart needs separate chambers and valves to keep oxygenated blood (blood that carries oxygen to the cells of the body) separate from de-oxygenated blood.

The upper chambers of the heart are called the left atrium and right atrium. The upper chambers of the heart receive blood. The lower chambers of the heart are called the left ventricle and the right ventricle. The lower chambers distribute the blood. The right side of the heart receives and sends out de-oxygenated blood and the left side of the heart receives and sends out oxygenated blood.

Valves within the heart prevent blood from flowing in the wrong direction. The tissue that separates one chamber from another is called a septum. The basic path of blood through the heart is as follows:

  • The right atrium receives oxygen-depleted blood from the body.
  • This blood then flows through the tricuspid valve into the right ventricle.
  • The right ventricle then pumps this blood through the pulmonary valve into the pulmonary artery and to the lungs to be replenished with oxygen.
  • Oxygen-rich blood from the lungs comes back to the heart through the pulmonary veins and is received by the left atrium.
  • This oxygen-rich blood then flows through the mitral valve into the left ventricle.
  • The left ventricle pumps the oxygenated blood through the aortic valve and into the aorta to be distributed throughout the body to replenish the cells with oxygen and nutrients.

A baby's heart begins to develop soon after conception. As the heart develops, structural defects that involve the chambers, walls, or valves of the heart, or the arteries and veins near the heart, can occur. These defects can disrupt the normal flow of blood through the heart and cause blood flow to slow down or go in the wrong direction or the wrong place, or can block blood flow completely. Congenital heart defects range in severity from undetectable to life threatening.

Diagram of Heart Anatomy
National Heart Lung and Blood Institute
of the
National Institutes of Health (NIH)

Incidence and Prevalence of Congenital Heart Defects

Currently, there are over 1 million people in the United States living with congenital heart defects. Each year in the United States, about 35,000 infants are born with a congenital heart defect (about 8 out of every 1,000 births). Approximately 25 percent of children with congenital heart defects require surgery to correct the condition.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 18 Nov 2008

Last Modified: 08 Sep 2015