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Tetralogy Of Fallot

  • Definition

    A congenital cardiac anomaly that consists of four defects: pulmonic stenosis, ventricular septal defect, malposition of the aorta so that it arises from the septal defect or the right ventricle, and right ventricular hypertrophy.


    tetralogy of fallot is actually four defects in combination.

    First, the septum that divides the two ventricles is incomplete (so there is a ventricular septal defect), and oxygen-poor blood is thus allowed to mix with oxygen-rich blood.

    Second, the passageway from the right ventricle to the lungs is markedly narrowed.

    Third, the origin of the aorta is shifted toward the right side of the heart from the left.

    Fourth, the muscle in the wall of the right ventricle is thickened and stiffened.

    Only the first two of these defects cause significant trouble or require an operation.

    Tetralogy of Fallot constitutes about 10 percent of all congenital heart disease. It is the most common cyanotic heart defect; nearly 3,000 new cases a year occur in the U.S..

    A French physician, Etienne Fallot, described this defect in 1888.


    The cause of this congenital abnormality is not known.


    These defects result in decreased blood flow to the lungs and circulation of blue (unoxygenated) blood to the body tissues; both of these effects cause bluish skin (cyanosis), clubbing (bulging of the nailbeds) of the fingers and toes, shortness of breath, and extreme fatigue.


    The condition is suspected on the basis of the child's symptoms and a physical examination. A chest x-ray shows a characteristic shape of the heart. An ecg, echocardiography, and in some cases cardiac catheterization are performed to determine the extent of the abnormality.


    Infants may require surgery (for example, the Blalock-Taussig shunt procedure) to improve blood flow to the lungs and decrease cyanosis. Once the child is past infancy, corrective open heart surgery is performed. The results of successful complete repair of Tetralogy of Fallot are good: cyanosis disappears, exercise tolerance improves, and people may lead normal lives.

    Without an operation, only about 30 percent of people with Tetralogy of Fallot would survive to the age of 40 years. Surgery results in almost 90 percent of patients surviving for at least 25 years from the time of surgery; generally, the results are best if the defect is corrected before the patient is 12 years old. If an infant has severe symptoms at an early age, placement of a temporary shunt may be required to provide more blood flow to the lungs.

    The long-term corrective procedure involves open-heart surgery, including two steps: closing the hole between the two ventricles and opening up the artery from the right ventricle to the lungs. The long-term results of the operation are good; most patients grow normally and have normal lives. A minority of patients have difficulties later in life with heart failure or heart rhythm disorders and may require additional surgery or continued medication.

    If surgery is considered necessary, it is usually performed electively when the child is between the ages of 2 and 4. The holes most often can be closed with a suture, but if they are particularly large, a small patch made from the patient's own pericardial (outside wrapping of the heart) tissue or a Dacron patch can be used.

    The operation provides a complete cure, and it is extremely rare for the holes to open up again. Antibiotic treatment to prevent infection need not be required for more than a few months after the operation, and the patient should be able to lead a full and active life.

    Patients receive antibiotics before dental or surgical procedures (bacterial endocarditis prophylaxis). Other medications may also be prescribed.


    How is tetralogy of Fallot diagnosed?

    Is it hereditary?

    Is surgery the only treatment method?

    How many similar surgeries have you performed? How many have been done in the hospital where this will be done?

    Will you be prescribing any heart-related medicines? If so, what are the side effects?