Tetralogy Of Fallot

Tetralogy of Fallot belongs to common congenital heart defects; it manifests in childhood and may severely impair the patient’s life. Fortunately, modern medicine brings us the possibility of an effective surgical treatment.


The disorder occurs already during the intrauterine development of the fetus. It is more common in males and its development is probably caused by a combination of genetic factors and external influences. The tetralogy of Fallot consists of four anatomical defects of the heart. These are faulty septum between hear ventricles, narrowing of the pulmonary artery (artery leading blood to the lungs for oxygenation), muscle hypertrophy of the right heart ventricle and change of location of the aortic outlet from the left ventricle. Tetralogy of Fallot may be further complicated by other heart defects.


Normally, deoxygenated blood flows from the right ventricle to the pulmonary artery and then to the lungs, where it is oxygenated. Oxygenated blood returns back to heart into its left side and then returns to the left side of the heart. From the left ventricle the oxygenated blood flows through the aorta into the rest of the body carrying nutrients and oxygen to the tissues.


In the tetralogy of Fallot the deoxygenated blood flows from the right ventricle directly to aorta because of the defect (a hole) in the septum between ventricles. This is further allowed by elevated pressure in the narrowed pulmonary artery (increased resistance to the blood flow) and closer anatomical relationship between the malpositioned aorta and the right ventricle.


High concentration of deoxygenated blood in aorta causes a bluish discoloration of tissues (technically cyanosis) such as the face, lips, mucous membranes, limbs, etc. In addition, the patient suffers from signs of heart failure such as fatigue and shortness of breath; he or she can experience sudden bouts of breathlessness, turning blue and unconsciousness. The patient has often clubbed fingers when the condition lasts for a long time.


The diagnosis is usually stated by a pediatrician. The important clues are the above mentioned symptoms and the outcome of physical examination. When listening with a stethoscope, there is often present a clearly audible heart murmur. When there is suspicion of a heart defect, it is necessary to perform an echocardiography to confirm or exclude the diagnosis.


When untreated, the tetralogy of Fallot has a poor prognosis killing about two thirds of untreated patient before they reach the age of ten. However, modern cardiosurgical methods can solve the defects and restore (more or less) the normal heart anatomy and its function, thus significantly improving the prognosis. People who underwent the surgical interventions remain in a regular outpatient cardiac monitoring.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Contact: jiri.stefanek@seznam.cz
 Sources: basic text sources