Disease: Tetralogy of Fallot

Overview

Tetralogy of Fallot (teh-TRAL-uh-jee of fuh-LOW) is a rare condition caused by a combination of four heart defects that are present at birth (congenital).

These defects, which affect the structure 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 because their blood doesn't carry enough oxygen.

Tetralogy of Fallot is often diagnosed during infancy or soon after. However, tetralogy of Fallot might not be detected until later in life in some adults, depending on the severity of the defects and symptoms.

With early diagnosis followed by appropriate surgical treatment, most children and adults who have tetralogy of Fallot live relatively normal lives, though they'll need regular medical care throughout life and might have restrictions on exercise.

Tetralogy of Fallot care at Mayo Clinic

Source: http://www.mayoclinic.com

Symptoms

Tetralogy of Fallot symptoms vary, depending on the extent of obstruction of blood flow out of the right ventricle and into the lungs. Signs and symptoms may include:

  • A bluish coloration of the skin caused by blood low in oxygen (cyanosis)
  • Shortness of breath and rapid breathing, especially during feeding or exercise
  • Loss of consciousness (fainting)
  • Clubbing of fingers and toes — an abnormal, rounded shape of the nail bed
  • Poor weight gain
  • Tiring easily during play or exercise
  • Irritability
  • Prolonged crying
  • A heart murmur

Tet spells

Sometimes, babies who have tetralogy of Fallot will suddenly develop deep blue skin, nails and lips after crying or feeding, or when agitated.

These episodes are called tet spells and are caused by a rapid drop in the amount of oxygen in the blood. Tet spells are most common in young infants, around 2 to 4 months old. Toddlers or older children might instinctively squat when they're short of breath. Squatting increases blood flow to the lungs.

When to see a doctor

Seek medical help if you notice that your baby has the following symptoms:

  • Difficulty breathing
  • Bluish discoloration of the skin
  • Passing out or seizures
  • Weakness
  • Unusual irritability

If your baby becomes blue (cyanotic), place your baby on his or her side and pull your baby's knees up to his or her chest. This helps increase blood flow to the lungs. Call 911 or your local emergency number immediately.

Source: http://www.mayoclinic.com

Causes

Tetralogy of Fallot occurs during fetal growth, when the baby's heart is developing. While factors such as poor maternal nutrition, viral illness or genetic disorders might increase the risk of this condition, in most cases the cause of tetralogy of Fallot is unknown.

The four abnormalities that make up the tetralogy of Fallot include:

  • Pulmonary valve stenosis. Pulmonary valve stenosis is a narrowing of the pulmonary valve — the valve that separates the lower right chamber of the heart (right ventricle) from the main blood vessel leading to the lungs (pulmonary artery).

    Narrowing (constriction) of the pulmonary valve reduces blood flow to the lungs. The narrowing might also affect the muscle beneath the pulmonary valve. In some severe cases, the pulmonary valve doesn't form properly (pulmonary atresia) and causes reduced blood flow to the lungs.

  • Ventricular septal defect. A ventricular septal defect is a hole (defect) in the wall (septum) that separates the two lower chambers of the heart — the left and right ventricles. The hole allows deoxygenated blood in the right ventricle — blood that has circulated through the body and is returning to the lungs to replenish its oxygen supply — to flow into the left ventricle and mix with oxygenated blood fresh from the lungs.

    Blood from the left ventricle also flows back to the right ventricle in an inefficient manner. This ability for blood to flow through the ventricular septal defect reduces the supply of oxygenated blood to the body and eventually can weaken the heart.

  • Overriding aorta. Normally the aorta — the main artery leading out to the body — branches off the left ventricle. In tetralogy of Fallot, the aorta is shifted slightly to the right and lies directly above the ventricular septal defect.

    In this position the aorta receives blood from both the right and left ventricles, mixing the oxygen-poor blood from the right ventricle with the oxygen-rich blood from the left ventricle.

  • Right ventricular hypertrophy. When the heart's pumping action is overworked, it causes the muscular wall of the right ventricle to thicken. Over time this might cause the heart to stiffen, become weak and eventually fail.

Some children or adults who have tetralogy of Fallot may have other heart defects, such as a hole between the heart's upper chambers (atrial septal defect), a right aortic arch or abnormalities of the coronary arteries.

Source: http://www.mayoclinic.com

Diagnosis

Your or your baby's doctor might suspect tetralogy of Fallot if he or she notices you or your baby has blue-tinged skin or a heart murmur — an abnormal whooshing sound caused by turbulent blood flow. Your or your baby's cardiologist will conduct a physical examination and use several tests to confirm the diagnosis.

Tests may include:

  • Echocardiography. Echocardiograms use high-pitched sound waves to produce an image of the heart. Sound waves bounce off the heart and produce moving images that can be viewed on a video screen.

    This test is generally used to diagnose tetralogy of Fallot. It allows your or your baby's doctor to determine if there is a ventricular septal defect and where it's located, if the structure of the pulmonary valve and pulmonary artery is normal, if the right ventricle is functioning properly, if the aorta is positioned properly, and if there are any other heart defects. This test can also help your or your baby's doctor to plan treatment for the condition.

  • Electrocardiogram. An electrocardiogram records the electrical activity in the heart each time it contracts. During this procedure, patches with wires (electrodes) are placed on your or your baby's chest, wrists and ankles. The electrodes measure electrical activity, which is recorded on paper.

    This test helps determine if the right ventricle is enlarged (right ventricular hypertrophy), if the right atrium is enlarged and if the heart rhythm is regular.

  • Chest X-ray. A chest X-ray can show the structure of the heart and lungs. A common sign of tetralogy of Fallot on an X-ray is a "boot-shaped" heart, because the right ventricle is enlarged.
  • Oxygen level measurement (pulse oximetry). This test uses a small sensor that can be placed on a finger or toe to measure the amount of oxygen in the blood.
  • Cardiac catheterization. Doctors may use this test to evaluate the structure of the heart and plan surgical treatment. During this procedure, your or your baby's doctor inserts a thin, flexible tube (catheter) into an artery or vein in the arm, groin or neck and threads it up to the heart.

    Your or your baby's doctor injects a dye through the catheter to make the heart structures visible on X-ray pictures. Cardiac catheterization also measures pressure and oxygen levels in the chambers of the heart and in the blood vessels.

Source: http://www.mayoclinic.com

Complications

All babies who have tetralogy of Fallot need corrective surgery. Without treatment, your baby might not grow and develop properly.

Your baby may also be at an increased risk of serious complications, such as infective endocarditis — an infection of the inner lining of the heart or heart valve caused by a bacterial infection.

Untreated cases of tetralogy of Fallot usually develop severe complications over time, which might result in death or disability by early adulthood.

Source: http://www.mayoclinic.com

Lifestyle and home remedies

After treatment, you might have some concerns about how best to manage your or your child's condition, including:

  • Preventing infection. A child, adolescent or adult who has severe heart defects might need to take preventive antibiotics before certain dental and surgical procedures. Your or your child's doctor can tell you if this is necessary. Maintaining good oral hygiene and getting regular dental checkups are excellent ways to help prevent infection.
  • Exercising. Parents of children or adolescents with congenital heart defects or adults who have congenital heart defects often worry about the risks of vigorous activity even after successful treatment.

    Although some children, adolescents or adults might need to limit the amount or type of exercise, many can lead normal or near-normal lives. Decisions about exercise need to be made on a case-by-case basis, so ask your or your child's doctor which activities are safe for you or your child.

If you're an adult who has congenital heart disease, you might have concerns, such as:

  • Employment. Having a congenital heart defect generally won't limit your career options. If you have serious heart rhythm problems or the potential for life-threatening complications, evaluation by a specialty team is needed to determine risk, provide therapy and counsel people regarding employment.
  • Pregnancy. Most women who have congenital heart disease tolerate pregnancy without any problems. However, a severe heart defect or complications such as arrhythmias can increase the risk of complications during pregnancy.

    If you have congenital heart disease, discuss family planning with your doctor. Your doctor may recommend that you be seen by a doctor trained in congenital heart disease before pregnancy and that you receive care during your pregnancy from doctors trained in congenital heart disease, genetics and high-risk obstetric care. Some heart medications aren't safe during pregnancy and might need to be stopped or adjusted before you become pregnant.

Source: http://www.mayoclinic.com

Coping and support

It can be extremely frightening to learn that you or your child has potentially life-threatening heart defects. Although support groups aren't for everyone, talking to other adults with congenital heart disease or to other parents — especially those whose children have already gone through corrective surgery — can give you hope, encouragement and support. Ask your or your child's doctor if there are any support groups for parents of children with heart defects or adults with congenital heart disease in your area.

If your child has a heart defect, be sure to give yourself a break at times. Ask other family members or friends to help take care of your child. When your child is in the hospital, see if you can schedule friends and family to visit with your child so that you can go home to take a shower or nap, or to spend time with your other children.

To help coordinate your or your child's care, you might prepare a brief note with your or your child's diagnosis, medications, surgeries and dates, and the cardiologist's name and number. This note will provide necessary information to others who might care for your child and will help any new doctor understand your or your child's health history.

If you change health insurance plans, be sure your new plan will cover your or your child's care. Some plans might not allow coverage for pre-existing conditions or might require a waiting period.

Source: http://www.mayoclinic.com

Risk factors

While the exact cause of tetralogy of Fallot is unknown, various factors might increase the risk of a baby being born with this condition. These risk factors include:

  • A viral illness during pregnancy, such as rubella (German measles)
  • Alcoholism during pregnancy
  • Poor nutrition during pregnancy
  • A mother older than age 40
  • A parent who has tetralogy of Fallot
  • The presence of Down syndrome or DiGeorge syndrome

Source: http://www.mayoclinic.com

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