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The tetralogy of Fallot is a congenital heart defect which classically has four anatomical components. It is the most common cyanotic heart defect and the most common cause of blue baby syndrome. Image File history File links Tetralogy_of_Fallot. ...
The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ...
The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ...
// Q00-Q99 - Congenital malformations, deformations and chromosomal abnormalities (Q00-Q07) Congenital malformations of the nervous system (Q00) Anencephaly and similar malformations (Q01) Encephalocele (Q02) Microcephaly (Q03) Congenital hydrocephalus (Q04) Other congenital malformations of brain (Q05) Spina bifida (Q06) Other congenital malformations of spinal cord (Q07) Other congenital malformations of nervous...
The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ...
The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ...
The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ...
The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ...
MedlinePlus (medlineplus. ...
eMedicine is an online clinical medical knowledge base that was founded in 1996. ...
A congenital heart defect is a defect in the structure of the heart and great blood vessels of the newborn. ...
Cyanosis refers to the bluish coloration of the skin due to the presence of deoxygenated hemoglobin in blood vessels near the skin surface. ...
A cyanotic newborn, or blue baby Blue baby syndrome (or simply, blue baby) is a laymans term used to describe newborns with cyanotic conditions, such as: Cyanotic heart defects Tetralogy of Fallot Dextro-Transposition of the great arteries Hypoplastic left heart syndrome Methemoglobinemia On November 29, 1944, the Johns...
It was described in 1672 by Niels Stensen and in 1888 by the French physician Etienne Fallot, for whom it is named. Events England, France, Munster and Cologne invade the United Provinces, therefore this name is know as ´het rampjaar´ (the disaster year) in the Netherlands. ...
Nicolaus Steno. ...
Year 1888 (MDCCCLXXXVIII) was a leap year starting on Sunday (click on link for calendar) of the Gregorian calendar (or a leap year starting on Tuesday of the 12-day slower Julian calendar). ...
Etienne Fallot (1850-1911) was a French physician born in Sète. ...
Anatomic morphology
As classically described, tetralogy of Fallot involves four heart malformations which present together: The heart and lungs, from an older edition of Grays Anatomy. ...
- A ventricular septal defect (VSD): a hole between the two bottom chambers (ventricles) of the heart. The defect is centered around the 'outlet septum', the most superior aspect of the septum, and in the majority of cases is single and large. In some cases septal hypertrophy can narrow the margins of the defect. [1]
- Pulmonic stenosis: Right ventricular outflow tract obstruction, a narrowing at (valvular stenosis) or just below (infundibular stenosis) the pulmonary valve. The stenosis is mostly the result of hypertrophy of the septoparietal trabeculae,[1] however the deviated outlet septum is believed to play a role. [2]. The degree of stenosis varies between individuals with TOF is the primary determinant of symptoms and severity. This malformation is infrequently described as sub-pulmonary stenosis or subpulmonary obstruction. [3]
- Overriding aorta: defined as when the aortic valve is not restricted to the left ventricle, thus having biventricular connections. The aortic root can be moved anteriorly or override the septal defect, but it is still to the right of the root of the pulmonary artery. The degree of override is quite variable, being between 5-95% of the valve being connected to the right ventricle.[1]
- Right ventricular hypertrophy: The right ventricle is more muscular than normal, causing a characteristic coeur-en-sabot (boot-shaped) appearance as seen by chest X-ray. Due to the misarrangement of the external ventricular septum, the right ventricular wall increase in size to deal with the increased obstruction to the right outflow tract. This feature is now generally agreed to be a secondary anomaly, as the level of hypertrophy generally increases with age. [4]
There is anatomic variation between the hearts of individuals with tetralogy of Fallot. The degree of right ventricular outflow tract obstruction varies between patients and is generally determines clinical symptoms and disease progression. Tetralogy of Fallot may present with other anatomical anomalies, including: A ventricular septal defect (or VSD) is a defect in the ventricular septum (the wall dividing the left and right ventricles of the heart). ...
Pulmonary valve stenosis (or, less commonly, pulmonic valve stenosis), abbreviated PVS, is a condition that can result in the reduction of flow of blood to the lungs. ...
The heart and lungs, from an older edition of Grays Anatomy. ...
An overriding aorta is a congenital heart defect where the aorta is positioned directly over a ventricular septal defect, instead of over the left ventricle. ...
The aortic valve is one of the valves of the heart. ...
Although ventricular hypertrophy may occur in either the left or right or both ventricles of the heart , left ventricular hypertrophy (LVH) is more commonly encountered. ...
The right ventricle is one of four chambers (two atria and two ventricles) in the human heart. ...
- stenosis of the left pulmonary artery, in 40% of patients
- a bicuspid pulmonary valve, in 40% of patients
- right-sided aortic arch, in 25% of patients
- coronary artery anomalies, in 10% of patients
- an atrial septal defect, in which case the syndrome is sometimes called a pentalogy of Fallot
- an atrioventricular septal defect
- partially or totally anomalous pulmonary venous return
- forked ribs and scoliosis
Tetralogy of fallot with pulmonary atresia or pseudotruncus arteriosus is a severe variant in which there is complete obstruction of the right ventricular outflow tract and absence of the pulmonary trunk. In these individuals, there is complete right to left shunting of blood. The lungs are perfused via extensive collaterals from the systemic arteries.
Epidemiology and etiology Tetralogy of Fallot occurs in approximately 3 to 6 per 10,000 births and represents 5-7% of congenital heart defects. Its cause is thought to be due to environmental or genetic factors or a combination. It is associated with chromosome 22 deletions and diGeorge syndrome. It occurs slightly more often in males than in females. DiGeorge syndrome is also called Microdeletion 22q11 syndrome (del 22q11. ...
Embryology studies show that it is a result of anterior malalignment of the conal septum, resulting in the clinical combination of a VSD, pulmonary stenosis, and an overriding aorta. Right ventricular hypertrophy results from this combination, which causes resistance to blood flow from the right ventricle.
Pathophysiology Tetralogy of Fallot results in low oxygenation of blood due to mixing of oxygenated and deoxygenated blood in the left ventricle through the VSD and preferential flow of both oxygenated and deoxygenated blood from the ventricles through the aorta because of obstruction to flow through the pulmonary valve. This is known as a right-to-left shunt. Oxygenation refers to the amount of oxygen in a medium. ...
Children with tetralogy of Fallot may develop acute severe cyanosis or hypoxic "tet spells". The precise mechanism of these episodes is in doubt, but presumably results from an increase in resistance to blood flow to the lungs with increased preferential flow of desaturated blood to the body.
Symptoms The primary symptom is low blood oxygen saturation with or without cyanosis from birth or developing in the first year of life. Without cyanosis, the baby is referred to as a "pink tet". Other symptoms include a heart murmur which may range from almost imperceptible to very loud, difficulty in feeding, failure to gain weight, retarded growth and physical development, dyspnea on exertion, clubbing of the fingers and toes, and polycythemia. Cyanosis refers to the bluish coloration of the skin due to the presence of deoxygenated hemoglobin in blood vessels near the skin surface. ...
Polycythemia is a condition in which there is a net increase in the total number of red blood cells in the body. ...
Tet spells are characterized by a sudden, marked increase in cyanosis, syncope, and may result in hypoxic brain injury and death.
Diagnosis Often a simple chest x-ray is enough to determine the presence of this condition. The heart may present with a "boot-like" appearance, rather than the symmetric appearance of a normal heart.
Treatment Tetralogy of Fallot is treated on two levels: with immediate emergency care for hypoxic or "tet" spells and with corrective surgery.
Emergency management of tet spells Consequential acute hypoxia may be treated with beta-blockers such as propranolol, but acute episodes may require rapid intervention with morphine to reduce ventilatory drive and phenylephrine to increase blood pressure. Oxygen is ineffective in treating hypoxic spells because the underlying problem is lack of blood flow through the pulmonary circuit and not alveolar oxygenation. There are also simple procedures such as the knee-chest position which increases aortic wave reflection, increasing pressure on the left side of the heart, decreasing the right to left shunt thus decreasing the amount of deoxygenated blood entering the systemic circulation.[5] Beta blockers or beta-adrenergic blocking agents are a class of drugs used to treat a variety of cardiovascular conditions and some other diseases. ...
Propranolol (INN) (IPA: ) is a non-selective beta blocker mainly used in the treatment of hypertension. ...
This article does not adequately cite its references or sources. ...
Phenylephrine or neosynephrine is an α-adrenergic receptor agonist used primarily as a decongestant, as an agent to dilate the pupil and, rarely, to increase blood pressure. ...
Palliative surgery The condition was initially thought untreatable until surgeon Alfred Blalock, cardiologist Helen B. Taussig, and lab assistant Vivien Thomas at Johns Hopkins University developed a surgical procedure, which involved forming an anastomosis between the subclavian artery and the pulmonary artery. It was actually Helen Taussig who convinced Alfred Blalock that the shunt was going to work. This redirected a large portion of the partially oxygenated blood leaving the heart for the body into the lungs, increasing flow through the pulmonary circuit, and greatly relieving symptoms in patients. The first Blalock-Taussig shunt surgery was performed on 15-month old Eileen Saxon on November 29, 1944 with dramatic results. Alfred Blalock (1899-1964) circa 1944 Alfred Blalock (April 5, 1899 – September 15, 1964) was a 20th century American innovator in the field of medical science most noted for his research on the medical condition of shock and the development of the Blalock-Taussig Shunt, surgical relief of the cyanosis...
Helen B(roke). ...
Vivien Theodore Thomas Vivien Thomas autobiography, Partners of the Heart: Vivien Thomas and His Work With Alfred Blalock Vivien Theodore Thomas (August 29, 1910 – November 26, 1985) was an African-American surgical technician who helped develop the procedures used to treat blue baby syndrome in the 1940s. ...
The Blalock-Taussig shunt is a surgical procedure to give palliation to cyanotic heart defects which are common causes of blue baby syndrome. ...
The Pott shunt and the Waterson procedure are other shunt procedures which were developed for the same purpose.
Currently, Blalock-Taussig shunts are not normally performed on infants with TOF except for severe variants such as TOF with pulmonary atresia.
Total surgical repair The Blalock-Taussig procedure was the only surgical treatment until the first total repair was performed in 1954. Between 1944 and when total repair became available at major surgical centers in the early 1960s, many infants and children were treated with Blalock-Taussig procedures.
The total repair was performed by C. Walton Lillehei at the University of Minnesota in 1954 on a 10-month boy. Total repair initially carried a high mortality risk which has consistently improved over the years. Surgery is now often carried out in infants 1 year of age or younger with a <5% perioperative mortality. The surgery generally involves making incisions into the heart muscle, relieving the right ventricular outflow tract stenosis by careful resection of muscle, and repairing the VSD using a Gore-Tex or Dacron patch or a homograft. Additional reparative or reconstructive work may be done on patients as required by their particular anatomy. Dr. C. Walton Lillehei (October 23, 1918–July 5, 1999) is known as the Father of Open-Heart Surgery. ...
Patients who have undergone "total" repair of tetralogy of Fallot often have good to excellent cardiac function after the operation with some to no exercise intolerance and have the potential to lead normal lives. Surgical success and long-term outcome greatly depends on the particular anatomy of the patient and the surgeon's skill and experience with this type of repair.
Prognosis Untreated, tetralogy of Fallot results in progressive right ventricular hypertrophy and dilatation due to the increased resistance on the right ventricle. The dilated cardiomyopathy progresses to right heart failure, usually with accompanying left heart failure. Actuarial survival for untreated tetralogy of Fallot is approximately 75% after the first year of life, 60% by four years, 30% by ten years, and 5% by forty years.
Patients with repaired tetralogy of Fallot have the potential to lead normal lives with continued excellent cardiac function, with some considerations:
Current techniques for total surgical repair greatly improve the hemodynamic function of the heart with tetralogy of Fallot but do not provide a lifetime correction of the defect. Ninety percent of patients with total repair as infants develop a progressively leaky pulmonary valve as the heart grows to its adult size. Patients also may have some degree of residual right outflow stenosis and damage to the electrical system of the heart from surgical incisions, causing abnormalities as detected by EKG and/or arrhythmias.
Long-term follow up studies show that this patient population is at risk for sudden cardiac death and for heart failure. Therefore, lifetime follow-up care by an adult congenital cardiologist is recommended to monitor these risks and to recommend treatment, such as interventional procedures or re-operation, if it becomes necessary.
As with patients that have undergone any heart surgery, antibiotic prophylaxis is indicated during dental treatment in order to prevent infective endocarditis.
References - ^ a b c Gatzoulis MA, Webb GD, Daubeney PE. (2005) Diagnosis and Management of Adult Congenital Heart Disease. Churchill Livingstone, Philadelphia. ISBN 0443071039.
- ^ Bartelings M, Gittenberger-de Groot A (1991). "Morphogenetic considerations on congenital malformations of the outflow tract. Part 1: Common arterial trunk and tetralogy of Fallot". Int. J. Cardiol. 32 (2): 213-30. PMID 1917172.
- ^ Anderson RH, Weinberg. The clinical anatomy of tetralogy of Fallot. Cardiol Young. 2005 15;38-47. PMID 15934690.
- ^ Anderson RH, Tynan M. Tetralogy of Fallot – a centennial review. Int J Cardiol. 1988 21; 219-232. PMID 3068155.
- ^ Murakami T (2002). "Squatting: the hemodynamic change is induced by enhanced aortic wave reflection". Am. J. Hypertens. 15 (11): 986-8. PMID 12441219.
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