Tetralogy of Fallot (TOF) is a congenital heart defect that is a combination of four heart defects. These defects of the heart cause oxygen-poor blood to flow out of the heart and to the rest of the body. Infants and children with tetralogy of Fallot usually have blue-tinged skin as result of low oxygen in the blood. This is usually termed as tet spells which develop after episodes of crying or feeding or when agitated. They are most common in young infants aged 2 or 4 months. It is also characterized by heart murmur, finger clubbing and difficulty in breathing.
There is no definite cause for tetralogy of Fallot. The disease is defined by four heart defects mainly pulmonary valve stenosis, ventricular septal defect, overriding aorta and right ventricular hypertrophy. Pulmonary valve stenosis is narrowing of the pulmonary valve which separates the lower right chamber of the heart from the main blood vessels leading to the lungs. Constriction of the valve leads to reduced blood flow to the lungs. Moreover, overgrowth of the heart muscle also leads to constriction below the pulmonary valve (infundibular stenosis). In ventricular septal defect, there is a hole in the wall separating the two lower chambers of the heart which is left and right ventricles. As a result deoxygenated blood gets mixed with fresh oxygenated blood leading reduced oxygen level in the blood.
In overriding aorta, the aortic valve (the main artery leading out to the body) is situated above the ventricular septal defect and is connected to both the right and left ventricle. The degree to which the aorta is attached to the right ventricle is referred to as the degree of “override”. This leads to mixing of oxygen-poor blood with oxygen-rich blood. In right ventricular hypertrophy over-working of the pumping action leads to thickening of the muscular wall of the right ventricle. This make the heart stiffen and become weak and eventually fail. This conditions or defects of the heart can occur in both infants and adults. Why this defects occur is not known or the cause behind it. They occur together and hence have been termed collectively as tetralogy of Fallot.
As tetralogy of Fallot has numerous health complications like infective endocarditis (an infection of the inner lining of the heart or heart valve caused by bacterial infection) and even death or disability (if untreated), it is essential to get proper diagnosis and treatment during the stage of infancy. Your baby’s treatment may be done by a multidisciplinary team consisting of cardiologist and pediatric specialists.
Your doctor will generally do a series of test consisting of echocardiography, electrocardiogram and chest X-rays which are the main test that produces images of the heart and helps the doctor plan a treatment procedure for the condition. A chest X-ray produces an image of the heart where the “boot shaped” sign is visible. Additional tests include oxygen level measurement (pulse oximetry) and cardiac catheterization.
The only possible of treatment for tetralogy of Fallot is surgery. There are two types of surgery, intracardiac (complete) repair and temporary operation, which are performed in conjuction or individually. Generally, a temporary operation is followed by an intracardiac repair.
Intracardiac repair is basically an open heart surgery performed in the first years after birth followed by a series of surgical repairs to correct the defects of the heart. The surgeon usually places a patch over the ventricular septal defect to close the hole between the lower chambers of the heart and also repairs or replaces the pulmonary valve to increase blood flow. He also removes the thickened muscles of the right ventricles. Sometimes a tube is placed between the right ventricle and the pulmonary artery. This is called a Rastelli repair.
In temporary surgery, also called palliative surgery, your doctor will create a bypass to improve blood flow to the lungs. It is done for both adults and babies. However, it is performed on babies prior to intracardiac repair, if he or she was born prematurely or the pulmonary artery is underdeveloped (hypoplastic). Therefore, talk to your doctor about the possible outcomes and complications of the surgeries before taking any decisions.
If your baby shows symptoms like difficulty breathing, bluish discolouration of the skin, passing out or seizures, weakness and unusual irritability, you should immediately take him or her to a doctor. Additional symptoms include clubbing of fingers and toes (abnormal, rounded shape of fingers) and tet spells. Tet spells are episodes where the baby develops deep blue skin, nails and lips right after crying or feeding or when agitated. Therefore, a baby showing one of these symptoms are eligible for tetralogy of Fallot treatment.
If your baby is suffering from other heart conditions or not showing any sign of the disease, then he or she is not eligible for the treatment of tetralogy of Fallot.
The surgical treatments for tetralogy of Fallot usually consist of numerous long-term complications like chronic pulmonary regurgitation (where blood leaks through the pulmonary valve back into the pumping chamber (right ventricle), heart valve problems (blood leaking through the tricuspid valve), holes in the wall between the ventricles that may continue to leak after repair or may need re-repair, enlarged right ventricle or left ventricle not working properly, irregular heartbeats (arrhythmias), coronary artery disease, aortic root dilation and sudden cardiac death. Other surgical risks include infection, bleeding or blood clots.
These complications can continue throughout childhood, adolescence and adulthood. However, the complications are further treated with more surgeries, heart catheterization and medications.
The treatment for tetralogy of Fallot involves a series of follow-up surgeries that are done to treat the complications arising due to the surgical operation. Due to the nature of the disease, post-treatment recovery and prevention is a lifelong process. It will include monitoring by a cardiologist specializing in congenital heart disease. There will be regular or monthly follow-ups and tests that evaluate the condition of the heart. Your doctor will give certain guidelines to follow like taking antibiotics during dental procedures to prevent infection as children with tetralogy of Fallot are at an increased risk for endocarditis. Also maintaining good oral hygiene helps. The doctor will also ask you to limit or stop doing any sort of physical activity as it will put increased pressure on your heart. However, these measures can vary from case to case.
Cautions should be taken for women who are pregnant as having tetralogy of Fallot can increase your complications or risk during pregnancy. But in most cases, the heart defect does not have any effects on pregnancy.
Recovery is a life-long process as tetralogy of Fallot requires numerous surgical repairs. Moreover, there will be restrictions such as no or less physical activity for the patient.
The treatment cost for tetralogy of Fallot is high ranging from Rs.2,00,000 to Rs.7,00,000.
No the results of the treatment is not permanent as the intracardiac repair is followed by more surgical operations to correct any complications arising out of the main surgery.
There are no alternative treatments for tetralogy of Fallot. The only treatment is surgical procedure.