Congenital Heart Disease

Tetralogy of Fallot

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

Tetralogy of Fallot is a combination of four heart defects that can result in a baby turning blue or cyanotic because of a lack of oxygen in the blood. It usually is diagnosed in infancy.

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. Valves that act as one-way doors control the flow between the chambers and between the arteries. The heart also has been pictured as two side-by-side pumps with one side pumping blood into the lungs and the other side pumping blood from the lungs back to the body.

Blood is pumped from the right side of the heart up 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 and is then pumped through another big blood vessel called the aorta to the rest of the body.

The four defects characteristic of this condition include:

• An abnormal opening in the wall separating the ventricles called a ventricular septal defect (VSD) that allows blood to go directly from the right to left ventricle without going through the lungs

• A narrowing of pulmonary valve or below the valve called pulmonary stenosis that partially blocks blood flow to the lungs

• An overly muscular right ventricle, also called right ventricular hypertrophy

• A displaced aorta, also called overriding aorta or Ao, directly over the abnormal opening between the ventricles

Babies with tetralogy are blue at birth or soon after, and have detectable heart murmurs, an extra sound in the heartbeat. Activity such as crying may exacerbate the condition and babies may have shortness of breath or may faint. Babies also may experience a "tetralogy spell" in which oxygen levels drop suddenly leading to irritability and then sleepiness or unresponsiveness.

Most adults with tetralogy of Fallot have had surgery during childhood. The adult with unrepaired tetralogy usually has milder cyanosis and a heart murmur or extra heart sound.

Reviewed by health care specialists at UCSF Medical Center.
Last updated December 18, 2008