Tetralogy of Fallot PDF - Congenital Heart Disease

Tetralogy of Fallot Straight to the point of care Last updated: Jul 18, 2023  Table of Contents Overview 3 Summary 3 Definition...

Tetralogy of Fallot Straight to the point of care Last updated: Jul 18, 2023  Table of Contents Overview 3 Summary 3 Definition 3 Theory 4 Epidemiology 4 Aetiology 4 Pathophysiology 4 Classification 6 Case history 6 Diagnosis 7 Approach 7 History and exam 9 Risk factors 9 Investigations 11 Differentials 13 Criteria 14 Screening 14 Management 15 Approach 15 Treatment algorithm overview 17 Treatment algorithm 18 Emerging 24 Secondary prevention 24 Patient discussions 24 Follow up 25 Monitoring 25 Complications 26 Prognosis 27 Guidelines 29 Diagnostic guidelines 29 Treatment guidelines 29 References 31 Images 37 Disclaimer 38 Tetralogy of Fallot Overview Summary Tetralogy of Fallot (TOF) is a ventricular septal defect with over-riding aorta and right ventricular (RV) outflow tract obstruction and resulting RV hypertrophy. The common embryological cause for this constellation of OVERVIEW findings is anterior and cephalad deviation of the muscular outlet of the ventricular septum. Usually presents in the neonatal period with a murmur, cyanosis, or both. Diagnosed by echocardiography. Treatment is by surgical repair. This usually consists of complete intracardiac repair typically during the neonatal or infant period. Occasionally, an aortopulmonary shunt is used palliatively before complete repair. The most common long-term complications of complete repair are progressive pulmonary regurgitation and RV failure, atrial arrhythmias, and ventricular arrhythmias. Definition TOF is a congenital cardiac malformation. The key morphological abnormality is anterior and cephalad deviation of the muscular outlet of the ventricular septum, which causes the 4 classic findings: (1) a mal- alignment ventricular septal defect (VSD), (2) aorta over-riding the VSD, (3) right ventricular outflow tract obstruction, (4) secondary concentric right ventricular hypertrophy. This was classically described in 1888 by Dr. Etienne-Louis Arthur Fallot, a pathologist, who coined the term 'la maladie bleue' (blue-baby syndrome). The cyanosis associated with this condition is due to right- to-left shunting of de-oxygenated blood at the level of the VSD. Historically, children with TOF presented with cyanosis that was progressive and life-limiting; untreated children with TOF would typically squat down, which would lead to increased pulmonary blood flow. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 3 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Theory Epidemiology Congenital heart defects are relatively common overall. During the early 1980s, an epidemiological study designed to estimate the prevalence of congenital heart disease (CHD) in the northeastern US showed the THEORY prevalence rate of CHD to be 3.7 per 1000 live births. There was a slight, but not statistically significant, male predominance and no ethnic difference. While it has been suggested that the incidence of CHD may be increasing over time, one meta-analysis of the literature suggests that this is largely due to an increasing ability to detect very minor cardiac lesions (e.g., trivial ventricular septal defects that will not need intervention). This report suggests that the overall incidence of severe forms of CHD has been stable over time at approximately 2.5/1000 to 3/1000 with moderate forms representing another 3/1000 live births. Of the severe forms of CHD, TOF is the most common cyanotic defect. It represents approximately 4% to 9% of all CHD and 30% of all cyanotic lesions. Globally, TOF is estimated to occur in 3 cases per 10,000 live births. In the US, the Centers for Disease Control and Prevention estimates that annually, 1 in 2518 babies are born with TOF. Aetiology Little is known about the exact aetiology of TOF. There is most likely to be interplay between genetic and environmental factors, but this has not been fully defined. One study of pregnant women with a first-degree relative with congenital heart disease (CHD) found 178 per 6640 (2.7%) pregnancies with CHD. There is a well-accepted association between certain genetic defects and CHD. Patients with trisomy 21, 18, or 13 have a higher incidence of TOF than infants without trisomy. A retrospective analysis in patients with apparently non-syndromic TOF found 10 out of 21 patients to have deletions of chromosome 22q11 (DiGeorge's and associated syndromes), suggesting a region on this chromosome may harbour a TOF susceptibility gene. In an earlier study comparing patients who had TOF with and without chromosome 22q11 deletion, every patient with TOF and 22q11 deletion was found to have an additional conotruncal anomaly. Alagille's syndrome, a syndrome with cardiovascular phenotypes ranging from mild pulmonary stenosis to TOF with severe pulmonary obstruction, has been found to be due to mutations in the Jagged1 gene. Additionally, mutations in Jagged1 have been associated with non-syndromic forms of TOF. A prospective study looking for mutations in NKX2.5 in patients with known TOF found approximately 4% of patients with non-syndromic TOF to have a mutation in NKX2.5. Increasing evidence suggests environmental factors may play a significant role in some cases of CHD. Maternal diabetes, maternal phenylketonuria, and maternal ingestion of retinoic acids or trimethadione have all been associated with an increased risk of CHD. Pathophysiology In TOF, the pathophysiology and management are dictated by 3 specific anatomical factors: 1. Degree of right ventricular outflow tract obstruction Typically occurs at multiple levels, including below the pulmonary valve (subvalvular or infundibular stenosis), at the level of the valve (valvular pulmonary stenosis), and above the valve (supravalvular stenosis). The degree of pulmonary obstruction determines whether the infant is cyanotic or acyanotic by affecting the amount of blood that shunts right to left at the ventricular septal defect (VSD). 4 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Theory TOF with mild pulmonary obstruction is typically not a cyanotic lesion. There is no significant restriction to the flow of blood into the pulmonary arteries and therefore the infant is well saturated. TOF and significant pulmonary obstruction result in a cyanotic infant. This is because blood in the right ventricle has a higher resistance to overcome in order to enter the pulmonary circulation. Blood is THEORY shunted from the right ventricle to the aorta through the VSD and into the systemic circulation without being oxygenated in the pulmonary circulation. 2. Pulmonary artery anatomy Pulmonary artery anatomy can dramatically affect the physiology. Pulmonary atresia with VSD (TOF with pulmonary atresia) and absent pulmonary valve syndrome (TOF with absent pulmonary valve) are very different physiologically and are considered different disease processes from TOF. For that reason, they are not discussed here. 3. Non-restrictive, mal-alignment VSD Anterior mal-alignment VSD in TOF is nearly always non-restrictive. With a large, non-restrictive VSD, the pressure in the right ventricle and left ventricle equalises. In this case, the VSD does not determine the degree of shunting. The degree of shunting in TOF is therefore due to the relative resistance to flow of the pulmonary versus systemic circulations. Additional VSDs may be present and should be looked for as these may complicate the postoperative course. Hypercyanotic spells, or tet spells, are episodes of severe cyanosis associated with hyperpnoea. They result from an increase in right ventricular outflow tract obstruction causing a decrease in the pulmonary blood flow and an increase in right-to-left shunting across the VSD. The exact aetiology of hypercyanotic spells is unclear, but they are thought to be initiated by increases in the right ventricular infundibular contractility. Hypercyanotic spells may be self-limited; however, if sustained, they can result in brain ischaemia or death. Anatomy and pathophysiology of tetralogy of Fallot (TOF): normal heart structure (a) promotes unidirectional flow of de-oxygenated blood (blue) into the lungs and oxygenated blood (red) into the aorta; in TOF (b) pulmonary stenosis and narrowing of the right ventricular outflow tract (RVOT) impedes the flow of de-oxygenated blood into the lungs, and both the ventricular septal defect (VSD) and overriding aorta (*) promote the flow of de-oxygenated blood into the systemic circulation, to produce cyanosis (sometimes referred to as 'blue baby' syndrome), right ventricular hypertrophy (RVH) is also present; (c) a Doppler echocardiogram shows mixing of de-oxygenated blood from the right ventricle (RV) and oxygenated blood from the left ventricle (LV) as blood is pumped out the over-riding aorta (Ao) in a patient with TOF (RA=right atrium, LA=left atrium) Multimedia Library of Congenital Heart Disease, Children’s Hospital, Boston, MA, editor Robert Geggel, MD; used with permission This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 5 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Theory Classification Variants of TOF THEORY There is no standard classification for TOF, but many experts would use the following classification: 1. Cyanotic TOF (also known as blue tet): infants with TOF and moderate to severe pulmonary obstruction are cyanotic at birth due to right-to-left shunting of de-oxygenated blood from the right ventricle across the VSD to the body. 2. Acyanotic TOF (also known as pink tet): infants with TOF and mild pulmonary obstruction are commonly acyanotic because there is little or no right-to-left shunting of blood at the ventricular level. These patients still undergo complete intracardiac repair. 3. Pulmonary atresia/VSD: sometimes referred to as TOF with pulmonary atresia and is anatomically and physiologically very different. It is often associated with malformation of the central pulmonary arteries. 4. Absent pulmonary valve syndrome: sometimes referred to as TOF with absent pulmonary valve. It is often associated with tracheobronchial compression and malformation. Case history Case history #1 A 1-day-old infant in the general care nursery born at full term by uncomplicated spontaneous vaginal delivery is noted to have cyanosis of the oral mucosa. The baby otherwise appears comfortable. On examination, respiratory rate is 40 and pulse oximetry is 80%. A right ventricular lift is palpated, S1 is normal, S2 is single, and a harsh 3/6 systolic ejection murmur is heard at the left upper sternal border. Case history #2 A 1-day-old infant in the general care nursery born at full term by uncomplicated spontaneous vaginal delivery is noted to have a murmur on examination. The baby otherwise appears well. On examination, respiratory rate is 40 and pulse oximetry is 96%. Precordium is normoactive. With auscultation, S1 is normal, S2 is single, and a 2/6 systolic ejection murmur is heard at the left upper sternal border. Other presentations Cyanosis occurs if severe right ventricular outflow tract obstruction forces blood returning to the right side of the heart to be shunted right to left across the ventricular septal defect and out to the systemic circulation, by-passing the lungs. Hypercyanotic spells may present as episodic, increasing cyanosis in a baby with TOF. The baby is typically crying and breathing deeply and rapidly, but may not be in significant respiratory distress. The typical murmur of TOF may disappear during the spell. This presentation is potentially life-threatening and requires rapid intervention. Alternatively, a baby may be severely cyanotic at birth. 6 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Diagnosis Approach Patients typically present with cyanosis and/or a murmur. Echocardiography is the definitive investigation for diagnosis of TOF and should be ordered in any newborn with a suspected diagnosis of congenital heart disease. History Certain genetic syndromes are associated with an increased incidence of TOF, such as DiGeorge and Down's syndromes. There may be a history of abnormality on fetal echocardiogram that suggests cardiac pathology. A typical infant presents in the newborn nursery with a murmur. Cyanosis is usually noted. The degree of cyanosis may vary and can be subtle, and some clinicians advocate routine screening of all neonates with pulse oximetry. Some infants may not present at birth but rather may present later with increasing cyanosis, murmur, or hypercyanotic (tet) spells. Hypercyanotic spells may present as episodic, increasing cyanosis in a baby with TOF. The baby is typically crying and breathing deeply and rapidly, but may not be in significant respiratory distress. The typical murmur of TOF may disappear during the spell. This presentation is potentially life-threatening and requires rapid intervention. TOF with severe pulmonary obstruction is a more severe presentation and may present in a newborn who appears severely cyanotic at birth. Infants with severe pulmonary obstruction or a hypercyanotic spell may present with severe cyanosis and acidosis due to tissue hypoxia. Physical examination Can vary significantly depending on the degree of pulmonary obstruction. The infant with mild obstruction is typically comfortable, and cyanosis may be difficult to discover on physical examination. With moderate obstruction the cyanosis is likely to be apparent on examination and the infant is typically comfortable. With severe obstruction the baby may have significant tachypnoea and cyanosis. DIAGNOSIS The cardiac examination typically finds an increased right ventricular (parasternal) impulse. S1 is normal and S2 is single. There is typically a 3/6 harsh systolic ejection murmur, heard best at the left sternal border. The murmur on examination represents blood flow across the pulmonary outflow and not the ventricular septal defect. The intensity of the murmur depends on the degree of pulmonary stenosis and decreases with severe stenosis. Investigations Transthoracic 2-dimensional and Doppler echocardiography is the preferred technique for defining the anatomical diagnosis. In the vast majority of cases no further testing is needed pre-operatively. Sedation may be judiciously used if the child is not co-operative with the examination. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 7 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Diagnosis Anatomy and pathophysiology of tetralogy of Fallot (TOF): normal heart structure (a) promotes unidirectional flow of de-oxygenated blood (blue) into the lungs and oxygenated blood (red) into the aorta; in TOF (b) pulmonary stenosis and narrowing of the right ventricular outflow tract (RVOT) impedes the flow of de-oxygenated blood into the lungs, and both the ventricular septal defect (VSD) and overriding aorta (*) promote the flow of de-oxygenated blood into the systemic circulation, to produce cyanosis (sometimes referred to as 'blue baby' syndrome), right ventricular hypertrophy (RVH) is also present; (c) a Doppler echocardiogram shows mixing of de-oxygenated blood from the right ventricle (RV) and oxygenated blood from the left ventricle (LV) as blood is pumped out the over-riding aorta (Ao) in a patient with TOF (RA=right atrium, LA=left atrium) Multimedia Library of Congenital Heart Disease, Children’s Hospital, Boston, MA, editor Robert Geggel, MD; used with permission Pre-ductal and post-ductal (right arm and either leg) pulse oximetry should be ordered if there is any suspicion of a congenital cardiac malformation. A hyper-oxygenation test can be used to determine whether hypoxaemia is from a pulmonary or a cardiac lesion. ECG will often show evidence of right ventricular hypertrophy and may show right axis deviation beyond normal limits for age. DIAGNOSIS ECG in tetralogy of Fallot showing right ventricular hypertrophy From the collection of Dr Jeffrey Gossett; used with permission A chest x-ray is classically described as a boot-shaped heart, but most patients do not have this finding. The presence of a right aortic arch may be noted in a subset of patients, particularly those with 22q11 deletion. Cardiac catheterisation is usually unnecessary in diagnosing TOF and may induce hypercyanotic spells. If there is significant concern for coronary artery anomalies that cannot be defined echocardiographically, then advanced imaging modalities including cardiac computed tomography angiography and magnetic resonance imaging are often used. Anomalies in the distribution or course of the coronary arteries may be present in approximately one third of patients with TOF. 8 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Diagnosis History and exam Key diagnostic factors hypercyanotic episodes (common) Hypercyanotic (tet) spells may present as episodic, increasing cyanosis in a baby with TOF. The baby is typically crying and breathing deeply and rapidly, but may not be in significant respiratory distress. The typical murmur of TOF may disappear during the spell. This presentation is potentially life-threatening and requires rapid intervention. Can occur in both cyanotic and acyanotic infants with TOF. harsh systolic ejection murmur (common) Loudest at the left sternal border represents the blood flow across the narrowed right ventricular outflow tract. cyanosis (common) Usually noted; however, the degree of cyanosis may vary and can be subtle. TOF with severe pulmonary obstruction is a more severe presentation and may present in a newborn who appears severely cyanotic at birth. tachypnoea (common) May have significant tachypnoea with severe pulmonary obstruction. Other diagnostic factors shock (uncommon) DIAGNOSIS Infants with severe pulmonary obstruction or a hypercyanotic spell may present with severe cyanosis and acidosis due to tissue hypoxia. Risk factors Weak trisomy 21, 18, or 13 There is a well-accepted association between certain genetic defects and congenital heart disease. Patients with trisomy 21, 18, or 13 have a higher incidence of TOF than infants without trisomy. chromosome 22q11 deletions (DiGeorge's syndrome) A retrospective analysis in patients with apparently non-syndromic TOF found 10 out of 21 patients to have deletions of chromosome 22q11 (DiGeorge's and associated syndromes), suggesting a region on this chromosome may harbour a TOF susceptibility gene. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 9 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Diagnosis Jagged1 gene mutations (Alagille's syndrome) Alagille's syndrome, a syndrome with cardiovascular phenotypes ranging from mild pulmonary stenosis to TOF with severe pulmonary obstruction, has been found to be due to mutations in the Jagged1 gene. Additionally, mutations in Jagged1 have been associated with non-syndromic forms of TOF. mutation in NKX2.5 gene A prospective study looking for mutations in NKX2.5 in patients with known TOF found approximately 4% of patients with non-syndromic TOF to have a mutation in NKX2.5. environmental factors Increasing evidence suggests environmental factors, such as maternal diabetes and phenylketonuria and maternal ingestion of retinoic acids and trimethadione, may play a significant causative role in certain cases of congenital heart disease. family history of congenital heart disease Believed to contribute to the recurrence of congenital heart disease in a family, but it cannot be clearly explained by mendelian genetics or complete penetrance. DIAGNOSIS 10 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Diagnosis Investigations 1st test to order Test Result pulse oximetry low ox ygen saturation Preductal and postductal (right arm and either leg) pulse oximetry should be ordered if there is any suspicion of a congenital cardiac malformation. May be normal in TOF with mild pulmonary stenosis. However, in TOF with moderate to severe pulmonary stenosis, the baby is hypoxaemic. echocardiogram infundibular pulmonary stenosis, over-riding Should be ordered in any newborn with a suspected diagnosis aorta, non-restrictive of congenital heart disease. Echocardiography is the definitive ventricular septal investigation for diagnosis of TOF. defect, concentric right ventricular hypertrophy ECG RVH with a rightwards axis, R in V1 and S in V6 Right ventricular hypertrophy (RVH) may be difficult to interpret in a above age-appropriate neonate. normals ECG in tetralogy of Fallot showing right ventricular hypertrophy From the collection of Dr Jeffrey Gossett; used with permission In an older child RVH is more likely to be seen. DIAGNOSIS CXR boot-shaped heart Normal cardiac silhouette does not rule out cyanotic heart disease. hyper-ox ygenation test no significant increase in PaO2 Used to determine whether hypoxaemia is from a pulmonary or a cardiac lesion. PaO2 on room air should be checked, 100% FiO2 given for at least 10 minutes, and then PaO2 re-checked. If the PaO2 increases by >25 mmHg and to >100 mmHg, the hypoxaemia is likely to be caused by a pulmonary problem. In acyanotic patients this test may yield false-negative results. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 11 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Diagnosis Other tests to consider Test Result cardiac CT angiography or MRI full definition of coronary anatomy Not routinely needed for evaluation in infants. Can be considered if definition of the coronary artery anatomy is not possible by echocardiography. cardiac catheterisation pulmonary stenosis and ventricular septal Not routinely done for diagnostic evaluation of TOF because defects may be seen on stimulation of the infundibular muscle may precipitate hypercyanotic angiogram; provides spells. haemodynamic data Occasionally intervention into the right ventricular outflow tract such as systemic right (RVOT) may be undertaken prior to complete repair with options ventricular pressure and including RVOT ballooning or stenting. right-to-left shunt DIAGNOSIS 12 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Diagnosis Differentials Condition Differentiating signs / Differentiating tests symptoms Other cyanotic congenital Includes single ventricle No change in PaO2 with cardiac abnormalities lesions such as hypoplastic hyperoxia test. left heart syndrome or Echocardiogram can define tricuspid atresia. Other anatomy to classify cyanotic possibilities include D- heart disease. transposition, pulmonary In some cases, a cardiac atresia, anomalous catheterisation may be pulmonary venous needed to further define connection, truncus anatomy and physiology. arteriosus, or Ebstein's anomaly. These may all be difficult to differentiate clinically from a cyanotic newborn with TOF. Most are not specifically associated with other syndromes, although this can vary. Pulmonary stenosis Usually presents in an Echocardiogram will show asymptomatic patient with presence or absence of a systolic ejection murmur typical anatomy of TOF with on examination. Difficult to pulmonary obstruction to differentiate clinically from differentiate from pulmonary TOF. stenosis alone. Ventricular septal defect At birth, an infant with simple Echocardiogram will show (VSD) VSD is fully saturated with presence or absence of regurgitant murmur on right-sided obstructive lesion examination. to determine whether this is DIAGNOSIS Intensity of murmur depends VSD alone or TOF. on size of VSD and flow across the VSD. A small VSD has a louder murmur because the gradient between the right and left ventricles is higher. A large VSD has a soft murmur because pressures are equalised between the right and left ventricles. As pulmonary vascular resistance drops, more blood shunts from left to right across the VSD and may result in pulmonary over- circulation and heart failure. This is uncommon with TOF, as the pulmonary obstruction prevents over-circulation. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 13 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Diagnosis Condition Differentiating signs / Differentiating tests symptoms Double outlet right Cannot be differentiated from Echocardiogram will show ventricle with normally TOF on physical examination presence or absence of related great vessels and alone. subaortic conus and degree pulmonary stenosis of aorta over-ride of the VSD to differentiate TOF from double outlet right ventricle. Primary pulmonary On examination, infant Hyper-oxygenation test disease may be tachypnoeic and should show increase in desaturated, potentially PaO2 with administration of requiring mechanical 100% FiO2. ventilation. CXR will show normal Cardiovascular examination cardiac silhouette with is usually normal. increased lung markings. Echocardiogram will show normal intracardiac anatomy. Criteria Echocardiogram findings of TOF Anterior and cephalad deviation of the muscular outlet of the ventricular septum resulting in: Mal-alignment ventricular septal defect Over-riding of the aorta Multi-level right ventricular outflow tract obstruction Right ventricular hypertrophy. DIAGNOSIS Screening There is an increase in the routine use of neonatal pulse-oximetry of all neonates for cyanotic heart disease. This has the potential to identify mildly cyanotic infants and should prompt further investigation of the neonate. All children with certain syndromes such as trisomy 21 should be screened for congenital heart disease (CHD). A screening fetal echocardiogram may be indicated in a pregnant mother who has had other children with CHD or has CHD herself. 14 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Management Approach The definitive treatment for TOF is complete surgical repair. All pre-operative patients with TOF need careful follow-up with their primary physician and a paediatric cardiologist. Attention to their weight gain is mandatory. Progression of cyanosis should be noted. Parents should be counselled to alert their physicians should they notice the onset of hypercyanotic spells, as these would be an indication for urgent surgical intervention. Management of hypercyanotic (tet) spells An infant with TOF and hypercyanotic spells is a medical emergency because a prolonged hypercyanotic spell can result in brain ischaemia and death. Management of a hypercyanotic spell consists of calming the child and manoeuvres to increase the amount of blood exiting the right ventricle to the pulmonary vasculature instead of to the aorta. Often the best place for the infant is in the parent's arms. Initially, the infant should be positioned with the knees to the chest as this will increase venous return to the heart (preload) and systemic afterload. Oxygen should be given, but care should be taken not to increase the infant's stimulation. If the infant is still profoundly cyanotic, acidosis will result. If these measures are not successful, medical therapy includes: Adjunctive supportive measures such as volume repletion, reversal of acidosis, or morphine Beta-blockers to relax the contracted infundibulum and to allow more time for right ventricular filling, improving pulmonary blood flow Phenylephrine as a final medical option to increase systemic venous resistance and force more blood to the lungs. Neonates with severely limited pulmonary blood flow causing profound cyanosis may benefit from prostaglandins (e.g., alprostadil) to maintain the patency of the ductus arteriosus. This provides an alternative source of pulmonary blood flow while the infant awaits urgent intervention. If all medical therapies fail to resolve a spell and the neonate or infant remains severely cyanotic, urgent intervention will be needed. Options include catheter-based right ventricular outflow tract ballooning or stenting, Blalock-Taussig shunt placement (a small GORE-TEX tube placed from a systemic artery to the pulmonary arteries to increase pulmonary blood flow), stenting of a patent ductus arteriosus, immediate complete repair, or extracorporeal membrane oxygenation. Propranolol has been used in the past in the outpatient setting of an infant with spells to delay surgery. An infant with a single spell is considered an indication for urgent surgical repair, but propranolol may be used until surgery can be arranged. Surgical management Over the last 10 to 15 years, there has been a trend towards neonatal repair of both cyanotic and MANAGEMENT acyanotic infants with TOF, but this is often determined by their pulmonary anatomy. In acyanotic patients without spells, repair is usually undertaken in the first year of life and has a very low morbidity and mortality. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 15 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Management Patients with TOF with severe pulmonary stenosis may undergo complete neonatal repair at some institutions or alternatively may undergo a Blalock-Taussig shunt or stenting of a patent ductus arteriosus in the newborn period before complete repair. Excellent results with complete repair in the neonatal period have been reported, with one cohort reporting a 5-year survival rate of 93% in patients with TOF who underwent complete repair as a neonate. Patients who undergo repair in childhood should be counselled about the possible need for future surgical or transcatheter interventions. In particular, if relief of pulmonary obstruction requires a transannular patch, there is likely to be a significant amount of postoperative pulmonary regurgitation. There is an increasing awareness of the need to monitor patients for progressive dilation of the right ventricle secondary to long-standing pulmonary regurgitation, and the need for pulmonary valve replacement in this setting. Typically, magnetic resonance imaging measurements are used to quantify the pulmonary regurgitation and right ventricular size. One group has suggested that valve replacement before the right ventricular diastolic volume reaches 160 mL/m² allows for normalisation of right ventricular volumes. Another group found that no patient with a right ventricular volume >170 mL/m² had normalisation of their right ventricular volumes after valve replacement. While there is no consensus on the exact criteria for the timing of replacement of the pulmonary valve, one review suggests using the following criteria: Repaired TOF or similar physiology with moderate or severe pulmonary regurgitation (regurgitation fraction ≥25% measured by cardiovascular magnetic resonance imaging) and 2 or more of the following criteria: Right ventricular end-diastolic volume index ≥160 mL/m² (Z score >5) Right ventricular end-systolic volume index ≥70 mL/m² Left ventricular end-diastolic volume index ≤65 mL/m² Right ventricular ejection fraction ≤45% Right ventricular outflow tract aneurysm Clinical criteria: exercise intolerance, symptoms and signs of heart failure, cardiac medications, syncope, or sustained ventricular tachycardia. Other haemodynamically significant lesions such as moderate or severe tricuspid regurgitation, residual atrial or ventricular septal defects, and severe aortic regurgitation may trigger referral for surgery in patients with moderate or severe pulmonary regurgitation. In the absence of the 6 criteria above, pulmonary valve replacement should be considered on a case-by-case basis. Due to a higher risk of adverse clinical outcomes in patients who underwent TOF repair at age ≥3 years, pulmonary valve replacement may be indicated sooner and in the presence of less severe right ventricular dilation and dysfunction. Infective endocarditis prophylaxis MANAGEMENT This is recommended pre-operatively and should be used for 6 months after repair. Those patients who have residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device should continue to receive lifelong infective endocarditis prophylaxis whenever undergoing an invasive 16 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Management procedure (e.g., dental procedures, or procedures on the respiratory tract or infected skin, skin structures, or musculoskeletal tissue). Treatment algorithm overview Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer Acute ( summary ) hypercyanotic spells 1st manoeuvres to increase systemic venous return adjunct supportive care 2nd beta-blocker adjunct supportive care 3rd phenylephrine adjunct supportive care neonate with profound cyanosis and severely limited pulmonary blood flow 1st alprostadil adjunct supportive care neonate or infant with non-remit ting severe cyanosis 1st surgical shunt, transcatheter stent/ balloon, or immediate complete repair adjunct extracorporeal membrane ox ygenation (ECMO) Ongoing ( summary ) all patients 1st complete surgical repair plus monitoring with possible pulmonary valve replacement MANAGEMENT adjunct infective endocarditis prophylaxis This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 17 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Management Treatment algorithm Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer Acute hypercyanotic spells 1st manoeuvres to increase systemic venous return » Infant should be kept calm and manoeuvres tried to increase the amount of blood exiting the right ventricle through the pulmonary vasculature instead of to the aorta. » Infant should be held in the parent's arms and positioned with the knees to the chest. adjunct supportive care Treatment recommended for SOME patients in selected patient group » Supportive medical therapy may include volume/blood administration as needed, intravenous morphine to calm the child as needed, and bicarbonate to reverse acidosis as needed. Oxygen should be given, but care should be taken not to increase the infant's stimulation. 2nd beta-blocker Primary options » esmolol: 100-500 micrograms/kg intravenous bolus initially, followed by 50-500 micrograms/kg/min infusion Bolus should be re-administered before maintenance dose is increased. OR » propranolol: 0.15 to 0.25 mg/kg intravenous bolus initially, may repeat in 15 min; 2-8 mg/ kg/day orally given in divided doses every 6 hours » Thought to help resolve hypercyanotic spells, but the mechanism of action is not completely clear. It is believed that it helps to decrease the infundibular obstruction by decreasing the heart rate, prolonging diastolic filling, and decreasing MANAGEMENT contractility. » May be initiated in patients with TOF with pulmonary stenosis if manoeuvres such as knee-to-chest positioning or fluid bolus have not resolved the hypercyanotic spell. 18 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Management Acute » Propranolol has been used in the past in the outpatient setting of an infant with spells to delay surgery. An infant with a single spell is considered an indication for urgent surgical repair, but propranolol may be used until surgery can be arranged. adjunct supportive care Treatment recommended for SOME patients in selected patient group » Supportive medical therapy may include volume/blood administration as needed, intravenous morphine to calm the child as needed, and bicarbonate to reverse acidosis as needed. Oxygen should be given, but care should be taken not to increase the infant's stimulation. 3rd phenylephrine Primary options » phenylephrine: 5-20 micrograms/kg intravenous bolus, followed by 0.1 to 0.5 micrograms/kg/min infusion » Used to increase systemic venous resistance by direct simulation of peripheral alpha- adrenergic receptors. » The goal is to increase the systemic vascular resistance above the resistance of the pulmonary outflow tract so that blood in the right ventricle preferentially flows through the pulmonary circulation, rather than across the ventricular septal defect and into the systemic circulation. » Used in the intensive care unit setting as the last medical option for management of hypercyanotic spells. It is initiated when positioning and beta-blocker agents have not increased pulmonary blood flow. adjunct supportive care Treatment recommended for SOME patients in selected patient group » Supportive medical therapy may include volume/blood administration as needed, intravenous morphine to calm the child as needed, and bicarbonate to reverse acidosis MANAGEMENT as needed. Oxygen should be given, but care should be taken not to increase the infant's stimulation. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 19 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Management Acute neonate with profound cyanosis and severely limited pulmonary blood flow 1st alprostadil Primary options » alprostadil: 0.02 to 0.1 micrograms/kg/min intravenously » May benefit from alprostadil (prostaglandin E1) to maintain the patency of the ductus arteriosus. This provides an alternative source of pulmonary blood flow while the infant awaits urgent intervention. » A potential adverse effect is apnoea, and mechanical ventilation may be required. Monitor for apnoea. adjunct supportive care Treatment recommended for SOME patients in selected patient group » Supportive medical therapy may include volume/blood administration as needed, intravenous morphine to calm the child as needed, and bicarbonate to reverse acidosis as needed. Oxygen should be given, but care should be taken not to increase the infant's stimulation. neonate or infant with non-remit ting severe cyanosis 1st surgical shunt, transcatheter stent/ balloon, or immediate complete repair » For neonates or infants with TOF and severe pulmonary obstruction in whom the pulmonary blood flow is significantly restricted, an alternative source of pulmonary blood flow may be necessary. » If all medical therapies fail to resolve a spell and the patient remains severely cyanotic, urgent intervention will be needed. » Options include catheter-based right ventricular outflow tract ballooning or stenting, stenting of a patent ductus arteriosus, Blalock- Taussig shunt placement (a small GORE- MANAGEMENT TEX tube placed from a systemic artery to the pulmonary arteries to increase pulmonary blood flow), or immediate complete repair. adjunct extracorporeal membrane ox ygenation (ECMO) 20 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Management Acute Treatment recommended for SOME patients in selected patient group » Emergent ECMO may be initiated to reverse cyanosis and acidosis before surgical intervention. MANAGEMENT This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 21 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Management Ongoing all patients 1st complete surgical repair » Specific treatment guidelines for surgical management of TOF do not exist, largely due to the complexity of the anatomical diversity among patients. » The anatomical variations in TOF, as well as its association with other cardiovascular anomalies, greatly influence the physiological consequences. » Additionally, surgical technique varies by surgical programme. Thus, the management of each patient is determined in consultation with cardiology and cardiovascular surgeons. plus monitoring with possible pulmonary valve replacement Treatment recommended for ALL patients in selected patient group » Patients who undergo repair in childhood should be counselled about the possible need for future surgical or transcatheter interventions.There is an increasing awareness of the need to monitor patients for progressive dilation of the right ventricle secondary to long- standing pulmonary regurgitation, and the need for pulmonary valve replacement in this setting. » Typically, magnetic resonance imaging measurements are used to quantify the pulmonary regurgitation and right ventricular size. While there is no consensus on the exact criteria for the timing of replacement of the pulmonary valve, one review suggests using the following criteria: » Repaired TOF or similar physiology with moderate or severe pulmonary regurgitation (regurgitation fraction ≥25% measured by cardiovascular magnetic resonance imaging) and 2 or more of the following criteria: right ventricular end-diastolic volume index ≥160 mL/m² (Z score >5); right ventricular end- systolic volume index ≥70 mL/m²; left ventricular end-diastolic volume index ≤65 mL/m²; right ventricular ejection fraction ≤45%; right ventricular outflow tract aneurysm; or clinical MANAGEMENT criteria (exercise intolerance, symptoms and signs of heart failure, cardiac medications, syncope, or sustained ventricular tachycardia). » Other haemodynamically significant lesions such as moderate or severe tricuspid 22 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Management Ongoing regurgitation, residual atrial or ventricular septal defects, and severe aortic regurgitation may trigger referral for surgery in patients with moderate or severe pulmonary regurgitation. In the absence of the 6 criteria above, pulmonary valve replacement should be considered on a case-by-case basis. » Due to a higher risk of adverse clinical outcomes in patients who underwent TOF repair at age ≥3 years, pulmonary valve replacement may be indicated sooner and in the presence of less severe right ventricular dilation and dysfunction. adjunct infective endocarditis prophylaxis Treatment recommended for SOME patients in selected patient group Primary options » cefalexin: 50 mg/kg orally as a single dose given 60 minutes before procedure, maximum 2000 mg/dose OR » amoxicillin: 50 mg/kg orally as a single dose given 60 minutes before procedure, maximum 2000 mg/dose OR » ampicillin: 50 mg/kg intravenously/ intramuscularly as a single dose given 30 minutes before fore procedure, maximum 2000 mg/dose » Cardiac surgery: directed primarily against staphylococci. First-generation cephalosporin (e.g., cefalexin) is most commonly used, but antibiotic choice depends on susceptibility patterns at each hospital. » Infective endocarditis prophylaxis before dental procedures or for procedures on the respiratory tract or infected skin, skin structures, or musculoskeletal tissue is required for unrepaired cyanotic congenital heart disease (CHD), including palliative shunts and repaired CHD with residual defects at or adjacent to the MANAGEMENT site of a prosthetic patch or device: directed primarily against enterococci. Amoxicillin or ampicillin is the preferred agent. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 23 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Management Emerging Percutaneous pulmonary valve In the complete surgical repair of TOF, there is dilation or reconstruction of the stenotic portion of the right ventricular outflow tract (RVOT). The repair of the RVOT depends on the anatomy of the pulmonary valve and artery, and infants frequently develop progressive pulmonary regurgitation (as in the case with transannular patch augmentation or progressive pulmonary obstruction) as they grow. It is not uncommon for TOF patients to need pulmonary valve replacement throughout their lives, necessitating multiple by-pass surgeries. Advancements have been made in the development of a transcatheter valved stent, and outcomes of 58 patients undergoing percutaneous pulmonary valve implantation in Europe have recently been reported. In this series, there were three major procedural complications and seven minor complications with no mortality. Secondary prevention Immunisation against respiratory syncytial virus is indicated during the appropriate season. Infective endocarditis prophylaxis before dental procedures or for procedures on the respiratory tract or infected skin, skin structures, or musculoskeletal tissue is required for unrepaired cyanotic congenital heart disease (CHD), including palliative shunts and repaired CHD with residual defects at or adjacent to the site of a prosthetic patch or device. Patients with TOF should have pre-conception counselling. Women with repaired TOF should be evaluated by a cardiologist before pregnancy. The risk of having an offspring with CHD increases 10-fold with an affected first-degree relative. A screening fetal echocardiogram may be indicated in a pregnant mother who has had other children with CHD or has CHD herself. There are no clear guidelines Patient discussions Patients should be aware that corrective repair does not mean a cure and further surgical intervention may be required. Patients need to be informed that having congenital heart disease (CHD) increases the risk of their own children having CHD, and that pre-conception genetic testing and fetal echocardiography may be indicated. As patients transition from adolescent to adult care, it is important to provide education on self- management and to help them build their medical knowledge. For example, ensure that they are equipped with the skills needed to make medical appointments and refill prescriptions, and that they understand the importance of lifestyle interventions such as weight management and non-smoking. MANAGEMENT 24 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Follow up Monitoring Monitoring FOLLOW UP Patients with surgically corrected TOF should be routinely assessed by a paediatric cardiologist. Neurodevelopmental follow-up is routinely indicated. Joint guidelines from the American College of Cardiology and American Heart Association recommend that adult patients with repaired TOF should have routine follow-up with a cardiologist who has expertise in adults with congenital heart disease (CHD) with recommended visit frequency and testing increasing based on the individual patients’ physiological stage and symptoms. They further advise that echocardiographic examinations and/ or magnetic resonance imaging (MRI) be performed on these patients by staff with expertise in adult CHD. Guidelines from the European Society of Cardiology (ESC) similarly recommend that adults with TOF be followed up in a specialised adult CHD centre. Pre-conception counselling and management during pregnancy is especially important for women with repaired TOF. Echocardiograms to evaluate right ventricular (RV) function and the progression of pulmonary stenosis or regurgitation should be performed every 1 to 5 years. The timing is patient specific, and patients with significant progressive RV dilation, pulmonary stenosis or regurgitation, or symptoms may require at least yearly scans. Cardiac MRI or computed tomography is an additional tool increasingly used to evaluate RV volume and function. MRI allows for accurate 3-dimensional measurements of RV volumes and is increasingly being used to determine timing of surgical pulmonary valve replacement. Often a multi-modality approach to imaging tailored to individual patient-specific considerations will need to be considered under the guidance of a congenital cardiologist. ESC guidelines recommend performing cardiac MRI at regular intervals according to TOF pathology. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 25 can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved.  Tetralogy of Fallot Follow up Complications Complications Timeframe Likelihood FOLLOW UP cyanotic spells short term medium Hypercyanotic spells present with dyspnoea and severe cyanosis. They result from contraction of the infundibular musculature creating increased right ventricular outflow tract obstruction and increased shunting of de-oxygenated blood from the right ventricle across the ventricular septal defect to the systemic circulation. Treatment of hypercyanotic spells is targeted towards relaxing the pulmonary obstruction and increasing systemic vascular resistance to increase the blood flow through the pulmonary circulation. paradoxical emboli short term low Preoperatively, patients with TOF have a ventricular septal defect (VSD), which allows communication of venous blood in the right heart with the systemic circulation. Normally, a thrombus in the venous circulation that embolises will be trapped in the pulmonary vasculature. However, the VSD provides communication such that a thrombus can paradoxically cross the VSD and lodge in an arterial bed, causing ischaemia. Patients with known communication between the right and left cardiac chambers should have precautions taken when using intravenous catheters, as an air bubble in the intravenous tubing can embolise to the systemic circulation, causing end-organ ischaemia. Prophylactic anticoagulation is not commonly given to patients with TOF. However, the possibility of venous thrombi should be carefully considered and treated aggressively if identified. progressive pulmonary regurgitation and right long term high ventricular failure A single-centre study of 100 consecutive adult patients with TOF repaired in childhood who underwent cardiac magnetic resonance imaging found poor right ventricular and left ventricular systolic function to be independent risk factors for impaired clinical status. ventricular arrhythmias long term medium While short-term results of surgical repair are good, the long-term results are limited by the development of arrhythmias. A retrospective analysis of 66 patients undergoing surgical repair of TOF between 1960 and 1993 found 28% to have no ventricular arrhythmias, 51% to have minor ventricular arrhythmias, 10.5% to have non-sustained ventricular tachycardia, and 9% to have sustained ventricular tachycardia or ventricular fibrillation. Serial ECGs have been performed to monitor the width of the QRS complex as an arrhythmogenic risk factor. If the QRS complex is noted to widen, further electrophysiological evaluation may be necessary. Some experts recommend periodic Holter monitors to screen for arrhythmia. Exercise testing is used by some clinicians. Ventricular arrhythmias may be managed with anti-arrhythmic drugs, transcatheter or surgical ablation, and/or implantation of an implantable cardioverter-defibrillator. 26 This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics can be found on bestpractice.bmj.com. Use of this content is subject to our disclaimer (. Use of this content is subject to our). © BMJ Publishing Group Ltd 2023. All rights reserved. Tetralogy of Fallot Follow up Complications Timeframe Likelihood atrial arrhythmias long term medium FOLLOW UP In the past decade, atrial arrhythmias have been increasingly recognised as a common long-term morbidity in repaired TOF. One retrospective study of adults with TOF repaired in childhood found that one third of patients had documented atrial arrhythmias, including sinus node dysfunction, atrial fibrillation, atrial flutter, and supraventricular tachycardia. Atrial arrhythmias are treated with transcatheter ablation or surgical ablation at the time of pulmonary valve replacement. sudden cardiac death long term low Sudden cardiac death from ventricular tachycardia or ventricular fibrillation is the most common cardiac cause of death in patients with repaired TOF. It is believed to be associated with progressive right ventricular failure. Ten years after surgery, the risk of sudden cardiac death increased from 0.06% per year to 0.2% per year. One retrospective analysis of patients undergoing surgical repair in 1 state in the US between 1958 and 1996 found that 11 out of 445 patients with repaired TOF died of sudden cardiac death. One retrospective study of 793 adult patients who underwent surgical repair for TOF in childhood at 6 different institutions found moderate to severe pulmonary regurgitation in 100% of patients who died of sudden cardiac death. congestive heart failure long term low Some patients with minimal pulmonary stenosis may have symptoms of heart failure. Furosemide is the most commonly used diuretic for symptoms of congestive heart disease. Care should be taken, as over- diuresis may precipitate hypercyanotic spells. Congestive heart failure is not a commonly recognised long-term complication of surgically repaired TOF. One single-centre study of 100 adults with TOF surgically repaired in childhood found 48% to be in New York Heart Association (NYHA) class I, 40% in class II, and 12% in class III. Prognosis Historically, the survival for untreated TOF was quite poor. In a report from the 1930s of 1000 patients with congenital heart disease, the average life expectancy for TOF was 12 years. Surgical outcomes are excellent with survival rates of 100% at 1 month, 93% at 1 year, and 93% at 5 years after complete repair. Freedom from reoperation rates were 100% at 1 month, 89% at 1 year, and 58% at 5 years. Once the patient has undergone complete surgical repair, the prognosis and any problems that occur may be related to the patient's individual anatomy and type of surgical repair, as well as any associated conditions. One study of survivors of the first year after surgical repair showed actuarial survival rates of 97% at 10 years, 94% at 20 years, 89% at 30 years, and 85% at 36 years. This PDF of the BMJ Best Practice topic is based on the web version that was last updated: Jul 18, 2023. BMJ Best Practice topics are regularly updated and the most recent version of the topics 27