Tetralogy of Fallot

I. Tetralogy of Fallot (Tet; TOF)

Tetralogy of Fallot refers to a type of congenital heart defect. Congenital means present at birth.

Causes Tetralogy of Fallot is classified as a cyanotic heart defect because the condition causes low oxygen levels in the blood. This leads to cyanosis (a bluish-purple color to the skin).

The classic form of tetralogy includes four related defects of the heart and its major blood vessels:

·  Ventricular septal defect (hole between the right and left ventricles)

·  Narrowing of the pulmonary outflow tract (the valve and artery that connect the heart with the lungs)

·  Overriding aorta (the artery that carries oxygen-rich blood to the body) that is shifted over the right ventricle and ventricular septal defect, instead of coming out only from the left ventricle

·  A thickened muscular wall of the right ventricle (right ventricular hypertrophy)

At birth, infants may not show signs of cyanosis. However, later they may develop sudden episodes (called "Tet spells") of bluish skin from crying or feeding.

Tetralogy of Fallot is rare, but it is the most common form of cyanotic congenital heart disease. Patients with tetraology of Fallot have a higher incidence of major non-heart congenital defects.

The cause of most congenital heart defects is unknown. Many factors seem to be involved.

Factors that increase the risk for this condition during pregnancy include:

·  Alcoholism in the mother

·  Diabetes

·  Mother who is over 40 years old

·  Poor nutrition during pregnancy

·  Rubella or other viral illnesses during pregnancy

There is a high incidence of chromosomal disorders in children with tetralogy of Fallot, such as Down syndrome and DiGeorge syndrome (a condition that causes heart defects, low calcium levels, and immune deficiency).

Symptoms

·  Clubbing of fingers (skin or bone enlargement around the fingernails)

·  Cyanosis, which becomes more pronounced when the baby is upset

·  Difficult feeding (poor feeding habits)

·  Failure to gain weight

·  Passing out

·  Poor development

·  Squatting during episodes of cyanosis

Exams and Tests

A physical examination with a stethoscope almost always reveals a heart murmur.

Tests may include:

·  Chest x-ray

·  Complete blood count (CBC)

·  Echocardiogram

·  Electrocardiogram (EKG)

·  MRI of the heart (generally after surgery)

Treatment

Surgery to repair tetralogy of Fallot is done when the infant is very young. Sometimes more than one surgery is needed. When more than one surgery is used, the first surgery is done to help increase blood flow to the lungs.

Surgery to correct the problem may be done at a later time. Often only one corrective surgery is performed in the first few months of life. Corrective surgery is done to widen part of the narrowed pulmonary tract and close the ventricular septal defect.

Outlook (Prognosis)

Most cases can be corrected with surgery. Babies who have surgery usually do well. Ninety percent survive to adulthood and live active, healthy, and productive lives. Without surgery, death usually occurs by the time the person reaches age 20.

Patients who have continued, severe leakiness of the pulmonary valve may need to have the valve replaced.

Regular follow-up with a cardiologist to monitor for life-threatening arrhythmias (irregular heart rhythms) is recommended.

Possible Complications

·  Delayed growth and development

·  Irregular heart rhythms (arrhythmias)

·  Seizures during periods when there is not enough oxygen

·  Death

II. Ventricular septal defect (VSD; Interventricular septal defect)

Ventricular septal defect describes one or more holes in the wall that separates the right and left ventricles of the heart. Ventricular septal defect is one of the most common congenital (present from birth) heart defects. It may occur by itself or with other congenital diseases.

Causes

Before a baby is born, the right and left ventricles of its heart are not separate. As the fetus grows, a wall forms to separate these two ventricles. If the wall does not completely form, a hole remains. This hole is known as a ventricular septal defect, or a VSD.

Ventricular septal defect is one of the most common congenital heart defects. The baby may have no symptoms, and the hole can eventually close as the wall continues to grow after birth. If the hole is large, too much blood will be pumped to the lungs, leading to heart failure.

The cause of VSD is not yet known. This defect often occurs along with other congenital heart defects.

In adults, ventricular septal defects are a rare but serious complication of heart attacks. These holes are related to heart attacks and do not result from a birth defect.

Symptoms

Patients with ventricular septal defects may not have symptoms. However, if the hole is large, symptoms, the baby often has symptoms related to heart failure.

The most common symptoms include:

·  Shortness of breath

·  Fast breathing

·  Hard breathing

·  Paleness

·  Failure to gain weight

·  Fast heart rate

·  Sweating while feeding

·  Frequent respiratory infections

Exams and Tests

Listening with a stethoscope usually reveals a heart murmur (the sound of the blood crossing the hole). The loudness of the murmur is related to the size of the defect and amount of blood crossing the defect.

Tests may include:

·  Chest x-ray -- looks to see if there is a large heart with fluid in the lungs

·  ECG -- shows signs of an enlarged left ventricle

·  Echocardiogram -- used to make a definite diagnosis

·  Cardiac catheterization (rarely needed, unless there are concerns of high blood pressure in the lungs)

·  MRI of the heart -- used to find out how much blood is getting to the lungs

Treatment

If the defect is small, no treatment is usually needed. However, the baby should be closely monitored by a health care provider to make sure that the hole eventually closes properly and signs of heart failure do not occur.

Babies with a large VSD who have symptoms related to heart failure may need medicine to control the symptoms and surgery to close the hole. Medications may include digitalis (digoxin) and diuretics.

If symptoms continue despite medication, surgery to close the defect with a Gore-tex patch is needed. Some VSDs can be closed with a special device during a cardiac catheterization, although this is infrequently done.

Surgery for a VSD with no symptoms is controversial. This should be carefully discussed with your health care provider.

Outlook (Prognosis)

Many small defects will close on their own. For those defects that do not spontaneously close, the outcome is good with surgical repair. Complications may result if a large defect is not treated.

Possible Complications

·  Heart failure

·  Infective endocarditis (bacterial infection of the heart)

·  Aortic insufficiency (leaking of the valve that separates the left ventricle from the aorta)

·  Damage to the electrical conduction system of the heart during surgery (causing arrhythmias)

·  Delayed growth and development (failure to thrive in infancy)

·  Pulmonary hypertension (high blood pressure in the lungs) leading to failure of the right side of the heart

When to Contact a Medical Professional

Most often, this condition is diagnosed during routine examination of an infant. Call your infant's health care provider if the baby seems to be having difficulty breathing, or if the baby seems to have an unusual number of respiratory infections.

Prevention

Except for the case of heart attack associated VSD, this condition is always present at birth.

Drinking alcohol and using the antiseizure medicines depakote and dilantin during pregnancy have been associated with increased incidence of VSDs. Other than avoiding these things during pregnancy, there is no known way to prevent a VSD.

Atrial septal defect

Atrial septal defect (ASD) is a congenital heart defect in which the wall that separates the upper heart chambers (atria) does not close completely. Congenital means the defect is present at birth.

Causes

In fetal circulation, there is normally an opening between the two atria (the upper chambers of the heart) to allow blood to bypass the lungs. This opening usually closes around the time the baby is born.

If the ASD is persistent, blood continues to flow from the left to the right atria. This is called a shunt. If too much blood moves to the right side of the heart, pressures in the lungs build up. The shunt can be reversed so that blood flows from right to left. Many problems can occur if the shunt is large, but small atrial septal defects often cause very few problems and may be found much later in life.

ASD is not very common. When the person has no other congenital defect, symptoms may be absent, particularly in children. Symptoms may begin any time after birth through childhood. Individuals with ASD are at an increased risk for developing a number of complications including:

·  Atrial fibrillation (in adults)

·  Heart failure

·  Pulmonary overcirculation

·  Pulmonary hypertension

·  Stroke

Symptoms

Small to moderate sized defects may produce no symptoms, or not until middle age or later. Symptoms that may occur can include:

·  Difficulty breathing (dyspnea)

·  Frequent respiratory infections in children

·  Sensation of feeling the heart beat (palpitations) in adults

·  Shortness of breath with activity

Exams and Tests

The doctor may hear abnormal heart sounds when listening to the chest with a stethoscope. A murmur may be heard only in certain body positions, and sometimes a murmur may not be heard at all. The physical exam may also reveal signs of heart failure in some adults.

If the shunt is large, increased blood flow across the tricuspid valve may create an additional murmur when the heart relaxes between beats.

Tests that may done include:

·  Cardiac catheterization

·  Chest x-ray

·  Coronary angiography (for patients over 35 years old)

·  Doppler study of the heart

·  ECG

·  Echocardiography

·  Heart MRI

·  Transesophageal echocardiography (TEE)

Treatment

ASD may not require treatment if there are few or no symptoms, or if the defect is small. Surgical closure of the defect is recommended if the defect is large, the heart is swollen, or symptoms occur.

A procedure has been developed to close the defect without surgery. The procedure involves placing an ASD closure device into the heart through tubes called catheters. The health care provider makes a tiny surgical cut in the groin, then inserts the catheters into a blood vessel and up into the heart. The closure device is then placed across the ASD and the defect is closed.

Not all patients with atrial septal defects can have this procedure.

Prophylactic (preventive) antibiotics should be given prior to dental procedures to reduce the risk of developing infective endocarditis immediately after surgery for the ASD, but they are not required later on.

Outlook (Prognosis)

With a small to moderate atrial septal defect, a person may live a normal life span without symptoms. Larger defects may cause disability by middle age because of increased blood flow and shunting of blood back into the pulmonary circulation.

Possible Complications

·  Arrhythmias, particularly atrial fibrillation

·  Heart failure

·  Pulmonary hypertension

·  Stroke

When to Contact a Medical Professional

Call your health care provider if symptoms indicating an atrial septal defect develop.

Prevention

There is no known way to prevent the defect, but some of the complications can be prevented with early detection.

·  Patent ductus arteriosus

Patent ductus arteriosus (PDA) is a condition in which a blood vessel called the ductus arteriosus fails to close normally in an infant soon after birth. (The word "patent" means open.)

The condition leads to abnormal blood flow between the aorta and pulmonary artery, two major blood vessels that carry blood from the heart.

Causes

Before birth, the ductus arteriosus allows blood to bypass the baby's lungs by connecting the pulmonary arteries (which supply blood to the lungs) with the aorta (which supplies blood to the body). Soon after the infant is born and the lungs fill with air, this blood vessel is no longer needed. It will usually close within a couple of days. If the ductus arteriosus does not close, there will be abnormal blood circulation between the heart and lungs.

PDA affects girls more often than boys. The condition is more common in premature infants and those with neonatal respiratory distress syndrome. Infants with genetic disorders, such as Down syndrome, and whose mothers had rubella during pregnancy are at higher risk for PDA.

PDA is common in babies with congenital heart problems, such as hypoplastic left heart syndrome, transposition of the great vessels, and pulmonary stenosis.

Symptoms

A small PDA may not cause any symptoms. However, some infants may not tolerate a PDA, especially if it is large, and may have symptoms such as:

·  Bounding pulse

·  Fast breathing

·  Poor feeding habits

·  Shortness of breath

·  Sweating while feeding

·  Tiring very easily

·  Poor growth

Exams and Tests

Babies with PDA often have a characteristic heart murmur that can be heard with a stethoscope. However, in premature infants, a heart murmur may not be heard. Doctor's may suspect the condition if the infant has breathing or feeding problems soon after birth.

Changes may be seen on chest x-rays. The diagnosis is confirmed with an echocardiogram.

Sometimes, a small PDA may not be diagnosed until later in childhood.

Treatment

The goal of treatment, if the rest of circulation is normal or close to normal, is to close the PDA. In the presence of certain other heart problems, such as hypoplastic left heart syndrome, the PDA may actually be lifesaving and medicine may be used to prevent it from closing.

Sometimes, a PDA may close on its own. Premature babies have a high rate of closure within the first 2 years of life. In full-term infants, a PDA rarely closes on its own after the first few weeks.

When treatment is appropriate, medications such as indomethacin or a special form of ibuprofen are generally the first choice.

If these measures do not work or can't be used, a medical procedure may be needed.

A transcatheter device closure is a minimally invasive procedure that uses a thin, hollow tube. The doctor passes a small metal coil or other blocking device through the catheter to the site of the PDA. This blocks blood flow through the vessel. Such endovascular coils have been used successfully as an alternative to surgery.