Editing Tetralogy of Fallot (section)

{{Short description|Type of congenital heart defect}}
{{Distinguish|Teratology}}
{{Infobox medical condition (new)
| name            = Tetralogy of Fallot
| image           = Tetralogy of Fallot.svg
| caption         = Diagram of a healthy heart and one with tetralogy of Fallot
| width           = 350px
| field           = [[Cardiac surgery]], [[pediatrics]]
| synonyms        = Fallot’s syndrome, Fallot’s tetrad, Steno–Fallot tetralogy<ref name=Name2016/>
| symptoms        = Episodes of [[cyanosis|bluish color to the skin]], difficulty breathing, [[heart murmur]], [[finger clubbing]]<ref name=NIH2011Sym/>
| complications   = [[Heart arrhythmia|Irregular heart rate]], [[pulmonary regurgitation]]<ref name=War2005/>
| onset           = From birth<ref name=NIH2011What/>
| duration        =
| types           =
| causes          = Unknown<ref name="Roos-Hesselink_2017"/>
| risks           = [[Alcohol (drug)|Alcohol]], [[diabetes]], >40, [[rubella]] during pregnancy<ref name="Roos-Hesselink_2017"/>
| diagnosis       = Based on symptoms, [[echocardiogram]]<ref name=NIH2011Diag>{{cite web|title=How Is Tetralogy of Fallot Diagnosed?|url=https://www.nhlbi.nih.gov/health/health-topics/topics/tof/diagnosis|website=NHLBI|access-date=7 May 2017|language=en|date=1 July 2011|url-status=live|archive-url=https://web.archive.org/web/20170429160101/https://www.nhlbi.nih.gov/health/health-topics/topics/tof/diagnosis|archive-date=29 April 2017}}</ref>
| differential    = [[Transposition of the great arteries]], [[Eisenmenger syndrome]], [[Ebstein anomaly]]<ref>{{cite book|vauthors=Prasad R, Kahan S, Mohan P|title=In a Page: Cardiology|date=2007|publisher=Lippincott Williams & Wilkins|isbn=9780781764964|url=https://books.google.com/books?id=7ODciw8IIF8C&pg=PA134|language=en|access-date=2017-09-15|archive-date=2021-05-15|archive-url=https://web.archive.org/web/20210515074550/https://books.google.com/books?id=7ODciw8IIF8C&pg=PA134|url-status=live}}</ref>
| prevention      =
| treatment       = [[Open heart surgery]]<ref name=NIH2011Tx/>
| medication      =
| prognosis       =
| frequency       = 1 in 2,000 babies<ref name=NIH2011What/>
| deaths          =
}}
<!-- Definition -->
'''Tetralogy of Fallot''' ('''TOF'''), formerly known as Steno-Fallot tetralogy,<ref name="Diaz-Frias_2021">{{cite book |vauthors=Diaz-Frias J, Guillaume M |chapter=Tetralogy of Fallot |date=2021 |chapter-url=http://www.ncbi.nlm.nih.gov/books/NBK513288/ |title=StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=30020660 |access-date=2021-12-05 |archive-date=2020-08-12 |archive-url=https://web.archive.org/web/20200812103313/https://www.ncbi.nlm.nih.gov/books/NBK513288/ |url-status=live }}</ref> is a [[congenital heart defect]] characterized by four specific cardiac defects.<ref name=NIH2011What>{{cite web|title=What Is Tetralogy of Fallot?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/tof/|website=NHLBI|access-date=2 October 2016|date=1 July 2011|url-status=live|archive-url=https://web.archive.org/web/20161004225713/http://www.nhlbi.nih.gov/health/health-topics/topics/tof|archive-date=4 October 2016}}</ref> Classically, the four defects are:<ref name="NIH2011What" />

*[[Pulmonary stenosis]], which is narrowing of the exit from the right ventricle;
* A [[ventricular septal defect]], which is a hole allowing blood to flow between the two [[ventricle (heart)|ventricle]]s;
* [[Right ventricular hypertrophy]], which is thickening of the right ventricular muscle; and
* an [[overriding aorta]], which is where the [[aorta]] expands to allow blood from both ventricles to enter.<!-- Symptoms -->

At birth, children may be asymptomatic or present with many severe symptoms.<ref name="Curr2016">{{Cite book |title=Current diagnosis & treatment: pediatrics | vauthors = Hay WW, Levin MJ, Deterding RR, Abzug MJ |isbn=9780071848541 |edition=23rd |location=New York |oclc=951067614|date=2016-05-02 }}</ref> Later in infancy, there are typically episodes of bluish colour to the skin due to a lack of sufficient oxygenation, known as [[cyanosis]].<ref name="NIH2011Sym" /> When affected babies cry or have a [[bowel movement]], they may undergo a "tet spell" where they turn cyanotic, have difficulty breathing, become limp, and occasionally [[unconsciousness|lose consciousness]].<ref name="NIH2011Sym" /> Other symptoms may include a [[heart murmur]], [[finger clubbing]], and easy tiring upon [[breastfeeding]].<ref name="NIH2011Sym">{{cite web|title=What Are the Signs and Symptoms of Tetralogy of Fallot?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/tof/signs|website=NHLBI|access-date=2 October 2016|date=1 July 2011|url-status=live|archive-url=https://web.archive.org/web/20161005191311/http://www.nhlbi.nih.gov/health/health-topics/topics/tof/signs|archive-date=5 October 2016}}</ref>

<!-- Cause and diagnosis -->
The cause of tetralogy of Fallot is typically not known.<ref name="Roos-Hesselink_2017" /> Maternal risk factors include lifestyle-related habits ([[alcohol (drug)|alcohol]] use during pregnancy, smoking, or recreational drugs), medical conditions ([[diabetes]]), infections during pregnancy ([[rubella]]), and advanced age of mother during [[pregnancy]] (35 years and older).<ref name="Roos-Hesselink_2017">{{cite book | vauthors = Roos-Hesselink JW, Johnson MR |title=Pregnancy and congenital heart disease |date=2017 |publisher=Springer |isbn=9783319389134 |location=Cham |pages=62 |oclc=969644876}}</ref>{{rp|62}} Babies with [[Down syndrome]] and other chromosomal defects that cause congenital heart defects may also be at risk of teratology of Fallot.<ref name="NIH2011Ca">{{cite web|title=What Causes Tetralogy of Fallot?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/tof/causes|website=NHLBI|access-date=2 October 2016 |date=1 July 2011 |url-status=live |archive-url =https://web.archive.org/web/20161005191259/http://www.nhlbi.nih.gov/health/health-topics/topics/tof/causes|archive-date=5 October 2016}}</ref> <!-- Treatment and prognosis -->

Teratology of fallot is typically treated by [[open heart surgery]] in the first year of life.<ref name=NIH2011Tx/> The timing of surgery depends on the baby's symptoms and size.<ref name=NIH2011Tx/> The procedure involves increasing the size of the [[pulmonary valve]] and [[pulmonary arteries]] and repairing the ventricular septal defect.<ref name=NIH2011Tx/> In babies who are too small, a temporary surgery may be done with plans for a second surgery when the baby is bigger.<ref name=NIH2011Tx>{{cite web|title=How Is Tetralogy of Fallot Treated?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/tof/treatment |website=NHLBI |access-date=2 October 2016|date=July 1, 2011|url-status=live|archive-url=https://web.archive.org/web/20161005191332/http://www.nhlbi.nih.gov/health/health-topics/topics/tof/treatment|archive-date=5 October 2016}}</ref> With proper care, most people who are affected live to be adults.<ref name=NIH2011What/> Long-term problems may include an [[Heart arrhythmia|irregular heart rate]] and [[pulmonary regurgitation]].<ref name=War2005>{{cite journal | vauthors = Warnes CA | title = The adult with congenital heart disease: born to be bad? | journal = Journal of the American College of Cardiology | volume = 46 | issue = 1 | pages = 1–8 | date = July 2005 | pmid = 15992627 | doi = 10.1016/j.jacc.2005.02.083 | doi-access = free }}</ref>

<!-- Epidemiology and history -->
The prevalence is estimated to be anywhere from 0.02 to 0.04% in the general population.<ref name=NIH2011What/> Though males and females were initially thought to be affected equally, more recent studies have found males to be affected more than females.<ref name=NIH2011What/><ref name="NORD"/> It is the most common complex congenital heart defect, accounting for about 10 percent of cases.<ref>{{Cite book |title=Johns Hopkins textbook of cardiothoracic surgery |date=2014 |publisher=McGraw-Hill Companies | vauthors = Yuh DD |isbn= 9780071663502 |edition=2nd |location=New York |oclc=828334087}}</ref><ref>{{cite web|title=Types of Congenital Heart Defects|url=http://www.nhlbi.nih.gov/health/health-topics/topics/chd/types|website=NHLBI|access-date=2 October 2016|date=1 July 2011|url-status=live|archive-url=https://web.archive.org/web/20161005180430/http://www.nhlbi.nih.gov/health/health-topics/topics/chd/types|archive-date=5 October 2016}}</ref> It was initially described in 1671 by [[Nicolas Steno|Niels Steensen]].<ref name=Name2016>{{cite web | vauthors = Lehn M |title=Fallot's tetralogy |url= http://www.whonamedit.com/synd.cfm/2281.html |website=Whonamedit? |access-date=2 October 2016 |url-status=live|archive-url= https://web.archive.org/web/20161003083817/http://www.whonamedit.com/synd.cfm/2281.html |archive-date=3 October 2016}}</ref><ref name=VanP2009>{{cite journal | vauthors = Van Praagh R | title = The first Stella van Praagh memorial lecture: the history and anatomy of tetralogy of Fallot | journal = Seminars in Thoracic and Cardiovascular Surgery. Pediatric Cardiac Surgery Annual | volume = 12 | pages = 19–38 | date = 2009 | pmid = 19349011 | doi = 10.1053/j.pcsu.2009.01.004 }}</ref> A further description was published in 1888 by the French physician [[Etienne Fallot|Étienne-Louis Arthur Fallot]], after whom it is named.<ref name=Name2016/><ref name=Fallot1888>{{Cite book|oclc=457786038|title=Contribution à l'anatomie pathologique de la maladie bleue (cyanose cardiaque), par le Dr. A. Fallot, ...| vauthors = Fallot A |date=1888|publisher=Impr. de Barlatier-Feissat|location=Marseille|pages=77–93|language=fr}}</ref> The first total surgical repair was carried out in 1954.<ref name=War2005/>
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