Tetralogy of Fallot an overview

Tetralogy of Fallot is a congenital heart disease that includes 4 specific defects:· Pulmonary valve stenosis (steh-NO-sis) is a narrowing of the pulmonary valve and the area below the valve. This slows the flow of blood from the right side of the heart to the lungs. The heart must pump harder to push blood through the smaller opening to the lungs where the blood picks up oxygen.· Ventricular septal defect (VSD) is a hole in the wall that separates the lower chambers (ventricles) of the heart.· Overriding aorta is a defect in the position of the large artery (aorta) that takes red (oxygen-rich blood) to the body. In a normal heart the aorta attaches to the left lower chamber of the heart (ventricle).

In tetralogy of Fallot, the aorta sits between the left and right ventricles, over the VSD. This causes mixing of red and blue (oxygen-poor) blood.· Right ventricular hypertrophy is the thickening of the right lower chamber of the heart (ventricle). Unlike other muscles in your body, when the heart thickens it does not work well. The heart has to pump harder to move blood through the narrowed pulmonary valve and the area below it.
Tetralogy of Fallot is a serious and complex heart defect that is present at birth. A baby's heart forms shortly after conception. By the end of the second month of pregnancy, the baby's heart is completely formed. It is during this time that tetralogy of Fallot can occur. It causes:· Less blood flow to the lungs· Mixing of red (oxygen-rich) and blue (oxygen-poor) blood inside the heart· Low levels of oxygen in the blood. When oxygen levels are low, the baby's skin, fingertips, or lips have a bluish tint. This is called a "blue baby" or cyanosis (SY-uh-NO-sis).Each year in the United States about 3,000 babies are born with tetralogy of Fallot. It is the congenital heart disease that causes the most cases of cyanosis.

Every infant or child with tetralogy of Fallot needs surgery, usually within the first year of life.· With advances in surgery and treatment many children born with tetralogy of Fallot have successful surgery and live to adulthood.Other Names for Tetralogy of Fallot· TOF· Fallot's

Tetralogy.

What Causes Tetralogy of Fallot?Doctors do not know the cause of most cases of tetralogy of Fallot. Heredity may play a role. In rare cases, more than one child in a family is born with a congenital heart defect like tetralogy of Fallot. Also, parents who have a congenital heart defect may be more likely than other parents to have a child with tetralogy of Fallot.Babies who have other birth defects, such as DiGeorge syndrome or Down syndrome, are also more likely to have tetralogy of Fallot.Other factors that increase the risk of a mother having a child with tetralogy of Fallot are: · Using alcohol or street drugs during pregnancy· Taking medications to control seizures during pregnancy· Having phenylketonuria (fen-el-key-toe-NEW-ree-a, or PKU)· Having viral infections such as German measles during pregnancy.Research continues to find the causes of congenital heart defects.

What Are the Signs and Symptoms of Tetralogy of Fallot?

Common Signs and SymptomsCyanosis is a common sign of tetralogy of Fallot. Cyanosis is the bluish tint of skin, lips, and nail beds caused by low levels of oxygen in the baby's blood. It usually occurs within the first few days to the first 2 weeks of life. The level of oxygen in the blood depends on:· The amount of narrowing of the pulmonary valve and surrounding area. The less narrowing of the pulmonary valve the better. This allows more blood to travel to the lungs to pick up oxygen. Increased narrowing of the pulmonary valve reduces blood flow to the lungs, lowering the amount of oxygen getting to the body.· Whether your baby has a patent ductus arteriosus (PDA) . A PDA is a persistent connection between the aorta and the pulmonary artery. This connection is called the ductus arteriosus and is normally present before birth. In most babies, the vessel closes within a few hours or days after birth. When the PDA stays open, blood mixes between the pulmonary artery and the aorta. More blood is sent back to the lungs to pick up oxygen.

A heart murmur may be the first sign found by your doctor. It is an extra or unusual sound heard during the baby's heartbeat. Most babies with tetralogy of Fallot have a heart murmur. The heart murmur may not be heard until after the baby is a few days old.Other Signs and SymptomsYour baby may have other symptoms, such as:· Rapid breathing· Cool and clammy skin· Pale skin color· Poor feeding because baby tires easily while nursing· Poor weight gain· Fussiness or irritability.Tetralogy "Spells"Some babies with tetralogy of Fallot have what is called a tetralogy "spell." A spell occurs when there is a sudden drop in the oxygen level in the blood. This causes the baby to become very blue. The baby may also:· Have a hard time breathing· Become very tired and limp· Not respond to your voice or touch· Become very fussy· Have a seizure.The cause of these spells is not known. They can happen when the baby is: · Upset · Has a low red blood cell count (anemia) · Has not gotten enough fluids. Babies who have a tetralogy spell need surgery as soon as possible. Each infant is different. Your baby's symptoms depend on the size and severity of the defects and if your baby has any other congenital heart defects.
How is Tetralogy of Fallot Diagnosed?Doctors diagnose tetralogy of Fallot by doing a physical exam of the baby and ordering tests. The signs and symptoms usually appear during the first weeks of life. Your infant's doctor may see them during a routine checkup. Some parents also notice signs of cyanosis or poor feeding and bring the baby to the doctor.If the doctor suspects that there is a problem with your baby's heart, you and your infant will be referred to a specialist who treats heart problems in children. The specialist, a pediatric cardiologist, will take a family and medical history, do a physical examination, and order several tests.Physical ExaminationDuring the physical examination, the doctor:· Listens to your baby's heart. The doctor uses a stethoscope to check for a heart murmur.· Looks for signs such as bluish color of skin and lips and rapid breathing.· Looks at general appearance. Some children with tetralogy of Fallot have a characteristic facial appearance that is associated with DiGeorge syndrome.· Listens to your baby's lungs.TestingAn echocardiogram is the test used most often to diagnose tetralogy of Fallot. This test uses sound waves to create a picture of the heart. An echocardiogram can show abnormal blood flow and problems with how the heart is formed. It is safe and painless.

During pregnancy, if your doctor suspects that your baby has a congenital heart defect, a special test called a fetal echocardiogram can be done. This test uses sound waves to create a picture of the baby's heart while still in the womb. It is usually done during the 5th month of pregnancy. This can help doctors plan treatment for your baby before he or she is born.Your baby may also have a cardiac catheterization if: · The results of the echocardiogram are not clear· The doctor suspects other heart problems.Cardiac catheterization is an invasive procedure. In this test:· A thin flexible tube is placed in the top of the baby's leg or arm and passed through an artery or vein to reach the heart.· Using x-rays, your baby's doctor can see the baby's blood vessels and heart. Your baby's doctor can also:· Measure the pressure inside the heart chambers· Determine how much red and blue blood is mixing between the 2 sides of the heart· See if the coronary arteries are normal.Other tests performed include:· Pulse oximetry .

This test uses a sensor to see how well your baby's lungs are passing oxygen to the blood and to check how much the red (oxygen-rich) blood and blue (oxygen-poor) blood are mixing. The sensor is placed on the baby's finger tip or toe (like a band aid). A small computer unit shows the amount of oxygen in the blood through the skin. This test is painless.· Chest x-ray. A chest x-ray takes a picture of your baby's heart and lungs. It can show if your child's heart is enlarged or if there is any fluid in the baby's lungs.· ECG or EKG (electrocardiogram). This test measures the rate and regularity of your baby's heartbeat.· Blood work to measure blood counts and oxygen levels.· A special blood test to see if your baby has DiGeorge syndrome.

How is Tetralogy of Fallot Treated?

All infants and children with tetralogy of Fallot must have surgery to repair the defects or help improve their symptoms.The goals of treatment are to:· Improve the baby's symptoms· Increase the level of oxygen in the baby's blood· Repair the defects.Most infants have surgery by the time they are 6 months old.Types of SurgeryCorrective SurgeryYour baby needs open-heart surgery to correct tetralogy of Fallot. The surgery includes:· Closing the hole in the inner wall of the heart between the lower chambers (VSD). A patch is used to cover the hole. This stops the mixing of blood between the chambers. The red (oxygen-rich) blood now flows out of the heart only to the body and the blue (oxygen-poor) blood goes to the lungs.· Opening and enlarging the area that blood flows through as it leaves the lower right side of the heart.

The thickened heart muscle is opened or a small amount of heart muscle is removed. This improves the flow of blue blood to the lungs so that it can pick up more oxygen.· Opening or widening the pulmonary valve (between the right ventricle and the pulmonary artery). The valve can be opened using a special instrument, but often a patch is sewn onto the heart to make the narrow area bigger. This increases blood flow out of the heart to the lungs.Your baby's heart doctor and heart surgeon decide the type of surgery needed and when it should happen based on:· The baby's health and weight· Severity of the baby's defects· Severity of the baby's symptoms.Sometimes, teenagers or adults need surgery to correct the right ventricular outflow tract.Temporary or Palliative SurgerySome babies are too weak to have open-heart surgery. They have temporary surgery to:· Reduce cyanosis (improve blood oxygen levels)· Give the baby time to grow and get stronger so the problem can be fixed later.The temporary surgery:· Is not open-heart surgery, but may be open-chest surgery· Does not repair the defect.Instead of open-heart surgery, a small opening can be made between the ribs. The procedure involves:· Placing a tube (called a shunt) between a large artery branching off the aorta and the pulmonary artery. · One end of the tube is sewn to the pulmonary artery and the other end is sewn to an artery branching off the aorta. This creates an additional pathway for blood to travel to the lungs.· This new pathway allows some of the blood in the aorta to flow through the tube into the pulmonary artery where it travels to the lungs to pick up oxygen.· The shunt is removed when your baby's defects are repaired during the corrective surgery.After surgery your baby may need medications to help keep the new blood pathway open.

Treatments

While Waiting for SurgeryYour baby may need other treatments before surgery. These treatments help the baby get stronger. They include:NutritionBabies with tetralogy of Fallot can tire while nursing or feeding. You may need to feed your baby more often. Some babies also need extra nutrition. This is given as a supplement or extra feeding. These feedings usually are formulas that give the baby extra calories. Many babies need extra vitamins or iron. Your pediatrician will decide what your baby needs. Lowering StressLowering your baby's anxiety or stress can help prevent tetralogy "spells" and save the baby's energy. You can try to predict what your baby needs to stop or lessen crying. Try picking up your infant slowly and speaking in a soothing voice to avoid startling or scaring the baby.Tetralogy "Spells"If your baby has a tetralogy spell you should:· Bring the baby's knees up tight against the baby's chest (the knee-chest position)· Attempt to calm the baby.After SurgeryAfter temporary surgery, your baby may need medications to keep the shunt open while you wait for the corrective surgery. These medicines are stopped after the shunt is removed during the corrective surgery.It is rare to need medications after the corrective surgery unless there are other problems. The scar from the surgery usually heals in about 6 weeks. Your surgeon or another member of the hospital staff will tell you when:· You can give your baby a bath· You can pick the baby up under the arms· Your baby should get his/her regular shots (immunizations).Your baby may need to take medicines to prevent a serious respiratory infection called respiratory syncytial virus (RSV). Because of the heart defect your baby may be more prone to get this infection. Your pediatrician or family doctor will decide if your baby needs any medicines to prevent RSV.

General Issues

It is important for your child to have regular medical care. This includes:· Lifetime follow up with a heart specialist· Following up with your child's pediatrician or family doctor for regular exams.Regular testing is usually recommended. These tests include:· Holter monitor· Echocardiogram· Exercise stress test.It is important for anyone with tetralogy of Fallot to have routine dental care to prevent tooth decay, which can lead to infections in the heart. Throughout your child's life, he or she should take antibiotics before any dental procedure, treatment, or cleaning. Talk to your doctor before going to the dentist. You may consider having your child wear a medic alert bracelet or necklace. This tells anyone caring for your child that the child has a congenital heart disease.Some children and adults with tetralogy of Fallot may need to limit certain types of exercise. The limits vary with each child. Discuss with your doctor:· If your child needs to restrict activity or exercise· If your child can play in organized sports, especially contact sports· The need for a note for school or coaches about limiting your child's exercise.Special Needs for ChildrenYour pediatrician or family doctor checks your child for growth and development at each routine checkup. Some children with tetralogy of Fallot do not grow and develop as fast as other children the same age. Most children "catch up" after surgery. However, some babies may need help. Your doctor may have your child tested for learning disabilities or refer you and your child for therapy with a specialist.

Pregnancy and Tetralogy of Fallot

Women with tetralogy of Fallot who want to become pregnant (or who are pregnant) need to:· Talk to their doctor about health risks during pregnancy· Talk to their doctor about medications that can be taken during pregnancy· Consult with specialists who take care of pregnant women with health conditions· Talk to their doctor about any new or worsening symptoms.
Summary·

Tetralogy of Fallot is a congenital heart disease that includes 4 specific defects:o Pulmonary valve stenosis: narrowing of the pulmonary valve and the area below the valve that slows the flow of blood from the right ventricle to the lungso VSD: a hole in the wall that separates the left and right ventricleso Overriding aorta: a defect where the aorta sits between the left and right ventricles, over the VSDo Right ventricular hypertrophy: thickening of the right ventricle. · Tetralogy of Fallot is a serious and complex type of heart defect that is present at birth. It causes:o Reduced blood flow to the lungso Mixing of red (oxygen-rich) and blue (oxygen-poor) blood inside the hearto Low levels of oxygen in the blood. · Cyanosis (bluish tint of skin, lips, and nail beds) is a common sign of tetralogy of Fallot. This happens when oxygen levels in the baby's blood are low.· Most babies with tetralogy of Fallot have a heart murmur (an extra or unusual sound heard during the baby's heartbeat).· Each year in the United States, about 3,000 babies are born with tetralogy of Fallot.· Doctors do not know what causes most cases of tetralogy of Fallot.· Babies who have other birth defects, such as DiGeorge syndrome or Down syndrome, are more likely to have tetralogy of Fallot.· Some babies have a sudden drop in the oxygen level in their blood. This is called a tetralogy "spell." When this happens your baby may:o Have a hard time breathingo Be very tired and limpo Not respond to your voice or toucho Be very fussyo Have a seizure.· If your baby has a tetralogy spell you should:o Put the baby in a knee-chest positiono Attempt to calm the baby · Doctors diagnose tetralogy of Fallot by doing a physical exam of your baby and ordering tests. · An echocardiogram is the test used most often to diagnose tetralogy of Fallot.· All infants and children with tetralogy of Fallot must have surgery to repair the defects or to help improve their symptoms. · Most infants have surgery by about 6 months of age. · With new advances in testing and treatment, most children who have tetralogy of Fallot fixed with surgery grow to adulthood and live healthy and productive lives.