Editing Cardiology (section)

=== Cardiac arrest ===
{{Main|Cardiac arrest}}

Cardiac arrest is a sudden stop in effective [[circulatory system|blood flow]] due to the failure of the heart to contract effectively.<ref name=NIH2016What/> Symptoms include [[unconsciousness|loss of consciousness]] and [[respiratory arrest|abnormal or absent breathing]].<ref name=Fie2009>{{cite book|last1=Field|first1=John M.|title=The Textbook of Emergency Cardiovascular Care and CPR|date=2009|publisher=Lippincott Williams & Wilkins|isbn=9780781788991|page=11|url=https://books.google.com/books?id=JaOoXdSlT9sC&pg=PA11|language=en}}</ref><ref name=NIH2016Sign/> Some people may have [[chest pain]], [[shortness of breath]], or [[nausea]] before this occurs.<ref name=NIH2016Sign>{{cite web|title=What Are the Signs and Symptoms of Sudden Cardiac Arrest?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/signs|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref> If not treated within minutes, [[death]] usually occurs.<ref name=NIH2016What>{{cite web|title=What Is Sudden Cardiac Arrest?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref>

<!-- Cause and diagnosis -->
The most common cause of cardiac arrest is [[coronary artery disease]].<!-- <ref name=NIH2016Ca/> --> Less common causes include [[bleeding|major blood loss]], lack of oxygen, [[hypokalemia|very low potassium]], [[heart failure]], and intense physical exercise.<!-- <ref name=NIH2016Ca/> --> A number of inherited disorders may also increase the risk including [[long QT syndrome]].<!-- <ref name=NIH2016Ca/> --> The initial heart rhythm is most often [[ventricular fibrillation]].<ref name=NIH2016Ca>{{cite web|title=What Causes Sudden Cardiac Arrest?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/causes|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref> The diagnosis is confirmed by finding no pulse.<ref name=Fie2009/> While a cardiac arrest may be caused by heart attack or heart failure these are not the same.<ref name=NIH2016What/>

<!-- Treatment and prognosis -->
Prevention includes not smoking, physical activity, and maintaining a healthy weight.<ref name=NIH2016Pre/> Treatment for cardiac arrest is immediate [[cardiopulmonary resuscitation]] (CPR) and, if a [[shockable rhythm]] is present, [[defibrillation]].<ref name=NIH2016Tx>{{cite web|title=How Is Sudden Cardiac Arrest Treated?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/treatment|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref> Among those who survive [[targeted temperature management]] may improve outcomes.<ref name="pmid27521472">{{cite journal | vauthors = Schenone AL, Cohen A, Patarroyo G, Harper L, Wang X, Shishehbor MH, Menon V, Duggal A | title = Therapeutic hypothermia after cardiac arrest: A systematic review/meta-analysis exploring the impact of expanded criteria and targeted temperature | journal = Resuscitation | volume = 108 | issue = | pages = 102–110 | date = November 2016 | pmid = 27521472 | doi = 10.1016/j.resuscitation.2016.07.238 }}</ref> An [[implantable cardiac defibrillator]] may be placed to reduce the chance of death from recurrence.<ref name=NIH2016Pre>{{cite web|title=How Can Death Due to Sudden Cardiac Arrest Be Prevented?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/prevention|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref>

<!-- Epidemiology and history -->
In the [[United States]], cardiac arrest outside of [[hospital]] occurs in about 13 per 10,000 people per year (326,000 cases). In hospital cardiac arrest occurs in an additional 209,000<ref name="pmid26472992">{{cite journal | vauthors = Kronick SL, Kurz MC, Lin S, Edelson DP, Berg RA, Billi JE, Cabanas JG, Cone DC, Diercks DB, Foster JJ, Meeks RA, Travers AH, Welsford M | title = Part 4: Systems of Care and Continuous Quality Improvement: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care | journal = Circulation | volume = 132 | issue = 18 Suppl 2 | pages = S397–413 | date = November 2015 | pmid = 26472992 | doi = 10.1161/CIR.0000000000000258 |doi-access=free}}</ref> Cardiac arrest becomes more common with age.<!-- <ref name=NIH2016Risk/> --> It affects males more often than females.<ref name=NIH2016Risk>{{cite web|title=Who Is at Risk for Sudden Cardiac Arrest?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/scda/atrisk|website=NHLBI|access-date=16 August 2016|date=June 22, 2016}}</ref> The percentage of people who survive with treatment is about 8%.<!-- <ref name=Adam2012/> --> Many who survive have significant [[disability]].<!-- <ref name=Adam2012/> --> Many U.S. television shows, however, have portrayed unrealistically high survival rates of 67%.<ref name=Adam2012>{{cite book|last1=Adams|first1=James G.|title=Emergency Medicine: Clinical Essentials (Expert Consult – Online)|date=2012|publisher=Elsevier Health Sciences|isbn=978-1455733941|page=1771|url=https://books.google.com/books?id=rpoH-KYE93IC&pg=PA1771|language=en}}</ref>