Tetralogy of Fallot can be detected during an ultrasound exam during pregnancy. If your clinical team suspects your baby may have TOF, they will order a fetal echocardiogram (cardiac ultrasound) to further
evaluate the structure of the heart and how it's functioning with this condition. Once your baby is born, a pediatric cardiologist will listen to your baby’s heart and lungs, feel the baby’s pulses, measure the oxygen level in the blood through pulse oximetry (a non-invasive test), and use other several tests to help clarify the diagnosis, including: Almost all children with tetralogy of Fallot will need surgery. Many children can be treated medically until a complete repair can be done. More severe forms of TOF may require early
intervention, including hospitalization. Most babies with TOF do not need heart catheterization, but sometimes this procedure can provide the care team with further information. In severe circumstances, some children need to have a stent placed via a catheter to open the heart’s connection to the lung artery. Children with TOF typically undergo surgery between 3 and 6 months of age. For most, a full repair surgery is performed as one
operation. But in rare instances, a child may require a series of operations. Then, an initial operation will place a Blalock-Taussig (BT) shunt, a tube connecting the lung artery with an artery near the heart, to increase blood flow to the lungs. This operation keeps the baby’s condition stable until further repairs can be done. However, at Boston Children’s Hospital we can also pursue, depending on your child’s condition, cutting-edge options in addition to a traditional BT shunt. Full
surgical repair of TOF consists of: If your child also has pulmonary atresia, surgeons will also reconnect the heart’s right ventricle to the pulmonary (lung) artery by placing a new valve or connecting tube. If
your child has major aortopulmonary collateral arteries (MAPCAs), they may need multiple procedures. Children with tetralogy of Fallot may need additional operations or catheterizations as they grow older. Although the goal of the initial operation is to provide the best long-term flow to the lungs, some children develop leakage from the lung valve, requiring replacement in the future. This often occurs in adolescence or early
adulthood, although it can happen sooner. Teenagers with congenital heart defects stay with their cardiologist until adulthood for medical appointments and procedures. Sometimes children need to limit physical activities, but there is still a lot that they can do. As adults, they will need to be followed by a congenital cardiologist because complications can arise in adulthood. TOF patients may be at some risk for
arrhythmias (abnormal heart rhythms), leaky valves, and other heart problems. Non-cardiac surgeries may pose risks for people with tetralogy of Fallot and will require evaluation and discussion with a cardiologist. For women with TOF, pregnancy may also present risks; our Adult Congenital Heart Program
has a team of doctors dedicated to this evaluation. Our team in the Boston Children’s Benderson Family Heart Center treats some of the most complex pediatric heart conditions in the world, with excellent results. Adults who were treated for congenital heart disease as children will need to be followed by a cardiologist because complications from
early heart disease can arise in adulthood. The Boston Adult Congenital Heart Program (BACH) is a world leader in the care of this unique patient population. Tetralogy of FallotNORD gratefully acknowledges Mary C. Mancini, MD, PhD, Department of Surgery, Louisiana State University Health Sciences Center, for assistance in the preparation of this report. Synonyms of Tetralogy of Fallot
General DiscussionSummary Tetralogy of Fallot is the most common form of cyanotic congenital heart disease. Cyanosis is the abnormal bluish discoloration of the skin that occurs because of low levels of circulating oxygen in the blood. Tetralogy of Fallot consists of the combination of four different heart defects: a ventricular septal defect (VSD); obstructed outflow of blood from the right ventricle to the lungs (pulmonary stenosis); a displaced aorta, which causes blood to flow into the aorta from both the right and left ventricles (dextroposition or overriding aorta); and abnormal enlargement of the right ventricle (right ventricular hypertrophy). The severity of the symptoms is related to the degree of blood flow obstruction from the right ventricle. Introduction The normal heart has four chambers. The two upper chambers known as atria are separated from each other by a fibrous partition known as the atrial septum. The two lower chambers are known as ventricles and are separated from each other by the ventricular septum. Valves connect the atria (left and right) to their respective ventricles. The valves allow for blood to be pumped through the chambers. Blood travels from the right ventricle through the pulmonary artery to the lungs where it receives oxygen. The blood returns to the heart through pulmonary veins and enters the left ventricle. The left ventricle sends the now oxygen-filled blood into the main artery of the body (aorta). The aorta sends the blood throughout the body. Ventricular Septal Defect The heart has an inner wall that separates the two chambers, called a septum. The septum stops mixing of the blood between the two sides. A ventricular septal defect is a hole in the septum that causes oxygen-rich blood (left ventricle) and the oxygen-poor blood (right ventricle) to mix. Pulmonary Stenosis This defect is the narrowing of the pulmonary valve, which flows oxygen poor blood into the pulmonary artery and from there the blood travels to the lungs to pick up oxygen. Pulmonary stenosis is when the pulmonary valve cannot open fully, making the heart work harder and results in a lack of blood reaching the lung. Right Ventricular Hypertrophy The muscle of the right ventricle is thicker due to the right side of the heart receiving excessive blood flow from the left side of the heart through the ventricular septal defect and working harder. Overriding Aorta In a normal heart, the aorta is attached to the left ventricle and allows oxygen-rich blood to flow throughout the body. In a tetralogy of Fallot heart, the aorta is located between both the left and the right ventricle. This causes oxygen-poor blood from the right ventricle to flow into the aorta instead of the pulmonary artery. If infants with tetralogy of Fallot are not treated, the symptoms usually become progressively more severe. Blood flow to the lungs may be further decreased and severe cyanosis may cause life-threatening complications. The exact cause of tetralogy of Fallot is not known. Signs & SymptomsThe symptoms of tetralogy of Fallot vary widely from person to person. The severity of the symptoms, which may range from mild to severe, is related to the degree of blood flow obstruction from the right ventricle. Tetralogy of Fallot may be present at birth or emerge within the first year of life. The most common symptom of this disorder is abnormal bluish discoloration of the skin (cyanosis). This may occur while the child is at rest or crying. The mucous membranes of the lips and mouth, fingertips, and toenails may be particularly blue due to the lack of oxygen. Affected infants may have difficulty breathing (dyspnea); as a result, they tend to play for short periods and then rest. Other symptoms may include a heart murmur, easy fatigability, poor appetite, slow weight gain, heart murmurs, an abnormal increase in the numbers of red blood cells (polycythemia), fingers and toes with wide, enlarged tips and overhanging nails (clubbing), and/or delayed physical growth. Some infants with tetralogy of Fallot may experience episodes of severe cyanosis and breathing difficulty (paroxysmal hypercyanotic attack or “blue” or “tet” spells). During these episodes, the infant may become restless, extremely cyanotic while gasping for air and nonresponsive to parent’s voices. In extreme situations, infants may pass out. A characteristic squatting position may be assumed to help assist breathing. Severe attacks may lead to the loss consciousness, and occasionally to convulsions or temporary paralysis on one side of the body (hemiparesis). These spells may last for a few minutes to a few hours and may be followed by periods of muscle weakness and a prolonged period of sleep. A variety of other complications may occur in association with tetralogy of Fallot. These may
include mild anemia in infants, abnormal increase in the number of red blood cells (polycythemia) in older children, and blood clotting (coagulation) defects. These blood abnormalities may lead to the formation of blood clots that can travel through the blood stream (embolisms). These blood clots may cause the blood supply to the brain (cerebral infarctions) to be interrupted temporarily. The most severe form of tetralogy of Fallot is known as pseudotruncus arteriosus. Infants with this form of the disorder experience severe symptoms that relate to the profound obstruction of the right ventricular blood flow and severe underdevelopment of associated blood vessels and valves related to the lungs (pulmonary atresia). Ventricular septal defects are usually severe in this form of the disorder. Severe cyanosis, alarmingly low levels of circulating oxygen, and excessive circulating red blood cells (polycythemia) are the major features of pseudotruncus arteriosus. (For more information, see “Ventricular Septal Defect” in the Related Disorders section of this report.) CausesThe exact cause of tetralogy of Fallot is not known. However, some studies suggest that the disorder may be due to the interaction of several genetic and/or environmental factors (multifactorial). Therefore, researchers suspect that something may affect the genes in the developing fetus, causing this birth defect, but the exact nature of this trigger is not known. Some conditions that may increase the risk of having a child with tetralogy of Fallot are viral illnesses, alcohol use, diabetes, poor nutrition, and being pregnant over the age of 40. Approximately 25 percent of infants with tetralogy of Fallot also have other congenital birth defects that are not related to the function or structure of the heart. Affected PopulationsTetralogy of Fallot is a rare congenital malformation of the heart that occurs more frequently in males than females. Approximately 1 percent of newborns have congenital heart defects. About 10 percent of these infants are diagnosed with tetralogy of Fallot. This heart defect is usually detected weeks or months after birth. The prevalence of tetralogy of Fallot is estimated to be 1 in 3,000 live births. Children with chromosome disorders, such as Down syndrome, often have tetralogy of Fallot and other congenital heart diseases. DiagnosisThe diagnosis of tetralogy of Fallot is confirmed by clinical evaluation and physical examination. A variety of specialized tests including electrocardiogram, echocardiogram, and cardiac catheterization may be performed to aid in diagnosis and therapy. When tetralogy of Fallot is present, x-ray studies usually reveal a normal-sized heart that is characteristically boot-shaped (coeur en sabot). Periodic measurements of systemic blood oxygen saturation and hemoglobin are also advisable. Infants with this disorder usually have a relatively loud murmur over the upper left breastbone. Standard TherapiesTreatment The definitive treatment for tetralogy of Fallot is surgery (i.e., Blalock-Taussig shunting procedure, aortic/pulmonary shunt, intracardiac repair, balloon pulmonary valvuloplasty and/or valve replacement). Surgical correction of this heart malformation is best accomplished during infancy. Selection of the exact surgical procedure is based on the severity of symptoms and extent of the malformation. The surgeon will widen the pulmonary valve and the passage from the right ventricle to the pulmonary artery is enlarged. A patch covers the hole in the septum to repair the ventricular septal defect. By resolving the VSD and the pulmonary valve problems, it fixes the other two defects. Temporary surgery may be recommended babies are too weak or small to have the full repair surgery; the full repair surgery will be performed when the baby is stronger. A tube or a “shunt” is placed between a large artery branching off the aorta and the pulmonary artery. It creates a pathway for blood to travel to the lungs to get oxygen. The tube is removed during the full repair surgery. When early repair is not possible, other surgical measures may be taken during infancy or early childhood. Prior to surgery, treatment to control symptoms (palliative) may include the maintenance of adequate fluid intake (hydration), monitoring of hemoglobin levels in the blood, and the avoidance of strenuous exercise. Heart medications (i.e., digitalis) may be prescribed to help control irregular heartbeats (arrhythmias), rapid heartbeats, and/or heart failure. Episodes of severe symptoms or “blue spells” (hypoxia) may require the administration of supplemental oxygen, morphine, and/or other drugs that improve oxygen concentration. The knee-chest position may also bring some symptomatic relief. Sodium bicarbonate may be administered to lower abnormally high levels of acid in the blood (acidosis). The drug propranolol may be given to help prevent future spells and to reduce their severity. Drugs that help to remove excess fluid from the body (diuretics), dietary salt restriction, and bed rest may be effective in treating congestive heart failure. Antibiotics may be prescribed to infants with tetralogy of Fallot to help prevent infections (prophylaxis) because children with this disorder are susceptible to bacterial infection of the heart (endocarditis). Respiratory infections must be treated vigorously and early. Children should be given antibiotics at times of predictable risk (e.g., tooth extractions and surgery). Other treatment is symptomatic and supportive. Although the risk for tetralogy of Fallot in the siblings of infants with this disorder is thought to be very low, genetic counseling may be of benefit for parents and other family members. Investigational TherapiesInformation on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site. For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office: For information about clinical trials sponsored by private sources, contact: For information about clinical trials conducted in Europe, contact: Supporting Organizations
ReferencesTEXTBOOKS Braunwald E, ed. Heart Disease. A Textbook of Cardiovascular Medicine. 3rd ed. Philadelphia, PA: W. B. Saunders Company; 1988:946-8, 988-91. JOURNAL ARTICLES Walker WT, et al. Quality of life after repair of tetralogy of Fallot. Cardiol Young. 2002;12:549-53. Mulder TJ, et al. A multicenter analysis of the choice of initial surgical procedure in tetralogy of Fallot. Pediatr Cardiol. 2002;23:580-86. Eldadah ZA, et al. Familial tetralogy of Fallot caused by mutation in the jagged1 gene. Hum Mol Genet. 2001;10:163-69. Goldmuntz E, et al. NKX2.5 mutations in patients with tetralogy of Fallot. Circulation. 2001;104:2565-68. Digilio MC, et al. Recurrence risk figures for isolated tetralogy of Fallot after screening 22q11 microdeletion. J Med Genet. 1997;34:188-90. Santoro G, et al. Echocardiographically guided repair of tetralogy of Fallot. Am J Cardiol. 1994;73:808-11. Sousa Uva M, et al. Surgery for tetralogy of Fallot at less than six months of age. J Thorac Cardiovasc Surg. 1994;107:1291-300. Yamagishi M, et al. Outflow reconstruction of tetralogy of Fallot using a Gore-Tex valve. Ann Thorac Surg. 1993;56:1416-17. Heinemann MK, et al. Preoperative management of neonatal tetralogy of Fallot with absent pulmonary valve syndrome. Thorac Surg. 1993;55:172-74. Murphy JG, et al. Long-term outcome in patients undergoing surgical repair of tetralogy of Fallot. N Engl J Med. 1993;329:593- 99. Warnes CA., Tetralogy of Fallot and pulmonary atresia/ventricular septal defect. Cardiol Clin. 1993;11:643-50. INTERNET McKusick VA, ed. Online Mendelian Inheritance in Man (OMIM). Baltimore. MD: The Johns Hopkins University; Entry No:187500; Last Update 9/30/2013.. http://omim.org/entry/187500. Accessed August 18, 2016. Weinrauch LA. Tetralogy of Fallot.
MedlinePlus. Last Update 10/22/2015. http://www.nlm.nih.gov/medlineplus/ency/article/001567.htm. Accessed August 18, 2016. Years Published1986, 1994, 1995, 1996, 2003, 2016 The information in NORD’s Rare Disease Database is for educational purposes only and is not intended to replace the advice of a physician or other qualified medical professional. The content of the website and databases of the National Organization for Rare Disorders (NORD) is copyrighted and may not be reproduced, copied, downloaded or disseminated, in any way, for any commercial or public purpose, without prior written authorization and approval from NORD. Individuals may print one hard copy of an individual disease for personal use, provided that content is unmodified and includes NORD’s copyright. National Organization for Rare Disorders (NORD) What are the 4 features of tetralogy of Fallot?Tetralogy of Fallot includes four defects:. Narrowing of the lung valve (pulmonary valve stenosis). ... . A hole between the bottom heart chambers (ventricular septal defect). ... . Shifting of the body's main artery (aorta). ... . Thickening of the right lower heart chamber (right ventricular hypertrophy).. How does tetralogy of Fallot present?Infants with tetralogy of Fallot can have a bluish-looking skin color―called cyanosis―because their blood doesn't carry enough oxygen. At birth, infants might not have blue-looking skin, but later might develop sudden episodes of bluish skin during crying or feeding. These episodes are called tet spells.
What is tetralogy of Fallot in infants?Tetralogy of Fallot (fah-LO) is a congenital (present at birth) heart defect. In tetralogy of Fallot (TOF), four related heart defects change the way blood flows to the lungs and through the heart. TOF is repaired through open-heart surgery soon after birth or later in infancy.
What is the most common complication of tetralogy of Fallot?If left untreated, it can cause these problems: Blood clots (which may be in the brain causing stroke) Infection in the lining of the heart and heart valves (bacterial endocarditis) Abnormal heart rhythms (arrhythmias)
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