Congenital Heart Disease

Transposition of Great Arteries

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

Transposition of the great arteries is when the two major arteries leaving the heart are connected to the wrong ventricles or lower chambers of the heart. The result is that blood containing oxygen from the lungs is pumped back into the lungs. Blood that lacks oxygen, which is necessary to nourish the body, is pumped throughout the body.

The heart consists of four chambers: the two upper chambers, called atria, where blood enters the heart, and the two lower chambers, called ventricles, where blood is pumped out of the heart. The flow between the chambers is controlled by a set of valves that act as one-way doors.

Normally blood is pumped from the right side of the heart through the pulmonary valve and the pulmonary artery to the lungs, where the blood is filled with oxygen. From the lungs, the blood travels back down to the left atrium and left ventricle. The newly oxygenated blood then is pumped through another big blood vessel called the aorta to the rest of the body.

A baby with transposed arteries is blue or cyanotic shortly after birth. The blueness doesn't go away even if the baby is given extra oxygen. For a baby with transposed arteries to survive, blood flow between the right and left sides of the heart must be increased.

Sometimes, other abnormalities may temporarily minimize the problem caused by this condition. For example, an atrial septal defect (ASD), an abnormal hole between the two atrial chambers where blood enters the heart, or a ventricular septal defect (VSD), an abnormal hole between the two ventricles, the chambers from which blood exits the heart, will allow blood to circulate between the two sides of the heart.

If the VSD is an alternative route for blood flow, the baby actually may get too much blood in the lungs. The baby won't be blue but may begin to suffer from congestive heart failure and have the symptoms of rapid breathing, poor feeding and sweating.

Another abnormality that could provide some short-term relief is a patent ductus arteriosus (PDA) that doesn't close normally after birth. The PDA is a connection between the aorta and pulmonary arteries that exists while a baby is in the womb and doesn't use its lungs. The PDA usually closes shortly after birth.

Babies with transposition may develop elevated pulmonary vascular resistance or pulmonary hypertension.

Reviewed by health care specialists at UCSF Children's Hospital.
Last updated May 8, 2007