Editing Heart (section)

===Diseases===
{{multiple image
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| image1 = Doctors stethoscope 1.jpg
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| caption1 = The stethoscope is used for [[auscultation]] of the heart, and is one of the most iconic symbols for [[medicine]]. A number of diseases can be detected primarily by listening for [[heart murmur]]s.
| image2 = 2113ab Atherosclerosis.jpg
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| caption2 = [[Atherosclerosis]] is a condition affecting the [[circulatory system]]. If the [[coronary arteries]] are affected, [[angina pectoris]] may result or at worse a [[heart attack]].
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[[Cardiovascular disease]]s, which include diseases of the heart, are the leading cause of death worldwide.<ref name="WHOfacts">{{Cite web|url=https://www.who.int/mediacentre/factsheets/fs317/en/|title=Cardiovascular diseases (CVDs)|website=World Health Organization|language=en-GB|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160310222948/http://www.who.int/mediacentre/factsheets/fs317/en/|archive-date=10 March 2016}}</ref> The majority of cardiovascular disease is noncommunicable and related to lifestyle and other factors, becoming more prevalent with ageing.<ref name="WHOfacts" /> Heart disease is a major cause of death, accounting for an average of 30% of all deaths in 2008, globally.<ref name="WHO CVD 2013" /> This rate varies from a lower 28% to a high 40% in [[World Bank high-income economy|high-income countries]].<ref name="Harrisons" /> Doctors that specialise in the heart are called [[cardiologist]]s. Many other medical professionals are involved in treating diseases of the heart, including [[Physician|doctors]], [[cardiothoracic surgeon]]s, [[intensivist]]s, and [[allied health profession|allied health practitioners]] including [[physiotherapist]]s and [[dietician]]s.<ref>{{Cite web|url=http://www.heart.org/HEARTORG/Conditions/HeartFailure/LivingWithHeartFailureAndAdvancedHF/Your-Heart-Failure-Healthcare-Team_UCM_306361_Article.jsp|title=Your Heart Failure Healthcare Team|website=www.heart.org|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160310073427/http://www.heart.org/HEARTORG/Conditions/HeartFailure/LivingWithHeartFailureAndAdvancedHF/Your-Heart-Failure-Healthcare-Team_UCM_306361_Article.jsp|archive-date=10 March 2016}}</ref>

==== Ischemic heart disease ====<!--Heart attack / AMI-->
{{main|Coronary artery disease}}

Coronary artery disease, also known as ischemic heart disease, is caused by [[atherosclerosis]]—a build-up of fatty material along the inner walls of the arteries. These fatty deposits known as atherosclerotic plaques [[stenosis|narrow]] the coronary arteries, and if severe may reduce blood flow to the heart.<ref name="WHFdiseases">{{Cite web|url=http://www.world-heart-federation.org/cardiovascular-health/heart-disease/different-heart-diseases/|title=Different heart diseases|website=World Heart Federation|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160312102709/http://www.world-heart-federation.org/cardiovascular-health/heart-disease/different-heart-diseases/|archive-date=12 March 2016}}</ref> If a narrowing (or stenosis) is relatively minor then the patient may not experience any symptoms. Severe narrowings may cause chest pain ([[angina]]) or breathlessness during exercise or even at rest. The thin covering of an atherosclerotic plaque can rupture, exposing the fatty centre to the circulating blood. In this case a clot or thrombus can form, blocking the artery, and restricting blood flow to an area of heart muscle causing a myocardial infarction (a heart attack) or [[unstable angina]].{{sfn|Harrison's|2011|p=1501}} In the worst case this may cause [[cardiac arrest]], a sudden and utter loss of output from the heart.{{sfn|Davidson's|2010|p=554}} [[Obesity]], [[high blood pressure]], uncontrolled [[diabetes]], smoking and high [[cholesterol]] can all increase the risk of developing atherosclerosis and coronary artery disease.<ref name="WHOfacts" /><ref name="WHFdiseases" />

==== Heart failure ====<!--Heart failure-->
{{main|Heart failure}}
Heart failure is defined as a condition in which the heart is unable to pump enough blood to meet the demands of the body.<ref name=":2" /> Patients with [[heart failure]] may experience breathlessness especially when lying flat, as well as ankle swelling, known as [[Peripheral edema|peripheral oedema]]. Heart failure is the result of many diseases affecting the heart, but is most commonly associated with [[Coronary artery disease|ischemic heart disease]], [[valvular heart disease]], or high blood pressure. Less common causes include various [[Cardiomyopathy|cardiomyopathies]]. Heart failure is frequently associated with weakness of the heart muscle in the ventricles (systolic heart failure), but can also be seen in patients with heart muscle that is strong but stiff (diastolic heart failure). The condition may affect the left ventricle (causing predominantly breathlessness), the right ventricle (causing predominantly swelling of the legs and an elevated [[jugular venous pressure]]), or both ventricles. Patients with heart failure are at higher risk of developing dangerous heart rhythm disturbances or [[Heart arrhythmia|arrhythmias]].<ref name=":2" />

==== Cardiomyopathies ====<!-- Cardiomyopathy -->
{{main|Cardiomyopathy}}Cardiomyopathies are diseases affecting the muscle of the heart. Some cause abnormal thickening of the heart muscle ([[hypertrophic cardiomyopathy]]), some cause the heart to abnormally expand and weaken ([[dilated cardiomyopathy]]), some cause the heart muscle to become stiff and unable to fully relax between contractions ([[restrictive cardiomyopathy]]) and some make the heart prone to abnormal heart rhythms ([[arrhythmogenic cardiomyopathy]]). These conditions are often genetic and can be [[Inherited disease|inherited]], but some such as dilated cardiomyopathy may be caused by damage from toxins such as alcohol. Some cardiomyopathies such as hypertrophic cardiomopathy are linked to a higher risk of sudden cardiac death, particularly in athletes.<ref name="CNX2014" /> Many cardiomyopathies can lead to heart failure in the later stages of the disease.<ref name=":2" />

==== Valvular heart disease ====<!-- Murmurs-->
{{main|Valvular heart disease}}{{listen|filename=Mitral Valve Prolapse.wav|title=Mitral Valve Prolapse murmur|description=Heart sounds of a 16 year old girl diagnosed with mitral valve prolapse and mitral regurgitation. Auscultating her heart, a systolic murmur and click is heard. Recorded with the stethoscope over the mitral valve.|format=[[wav]]}}Healthy heart valves allow blood to flow easily in one direction, and prevent it from flowing in the other direction. A diseased heart valve may have a narrow opening ([[stenosis]]), that restricts the flow of blood in the forward direction. A valve may otherwise be leaky, allowing blood to leak in the reverse direction ([[Regurgitation (circulation)|regurgitation]]). Valvular heart disease may cause breathlessness, blackouts, or chest pain, but may be asymptomatic and only detected on a routine examination by hearing abnormal heart sounds or a [[heart murmur]]. In the developed world, valvular heart disease is most commonly caused by degeneration secondary to old age, but may also be caused by infection of the heart valves ([[endocarditis]]). In some parts of the world [[Rheumatic Heart Disease|rheumatic heart disease]] is a major cause of valvular heart disease, typically leading to mitral or aortic stenosis and caused by the body's immune system reacting to a [[Group A streptococcal infection|streptococcal]] throat infection.<ref name=":4" />{{sfn|Davidson's|2010|pp=612–613}}

==== Cardiac arrhythmias ====<!-- Abnormalities of rhythm-->
{{main|Arrhythmia}}
{{Listen|filename=|title=An irregular heartbeat|description=Recording of heart sounds from a 16-year-old girl with a cardiac arrhythmia.|pos=[[wav]]}}
While in the healthy heart, waves of electrical impulses originate in the [[Sinoatrial node|sinus node]] before spreading to the rest of the atria, the [[atrioventricular node]], and finally the ventricles (referred to as a [[Sinus rhythm|normal sinus rhythm]]), this normal rhythm can be disrupted. Abnormal heart rhythms or arrhythmias may be asymptomatic or may cause palpitations, blackouts, or breathlessness. Some types of arrhythmia such as [[atrial fibrillation]] increase the long term risk of [[stroke]].<ref name=":3" />

Some arrhythmias cause the heart to beat abnormally slowly, referred to as a [[bradycardia]] or bradyarrhythmia. This may be caused by an [[Sick sinus syndrome|abnormally slow sinus node]] or damage within the cardiac conduction system ([[heart block]]).<ref name=":1" /> In other arrhythmias the heart may beat abnormally rapidly, referred to as a [[tachycardia]] or tachyarrhythmia. These arrhythmias can take many forms and can originate from different structures within the heart—some arise from the atria (e.g. [[atrial flutter]]), some from the atrioventricular node (e.g. [[AV nodal reentrant tachycardia|AV nodal re-entrant tachycardia]]) whilst others arise from the ventricles (e.g. [[ventricular tachycardia]]). Some tachyarrhythmias are caused by scarring within the heart (e.g. some forms of [[ventricular tachycardia]]), others by an irritable focus (e.g. focal [[atrial tachycardia]]), while others are caused by additional abnormal conduction tissue that has been present since birth (e.g. [[Wolff–Parkinson–White syndrome|Wolff-Parkinson-White syndrome]]). The most dangerous form of heart racing is [[ventricular fibrillation]], in which the ventricles quiver rather than contract, and which if untreated is rapidly fatal.<ref>{{Cite journal|last1=Blomström-Lundqvist|first1=Carina|last2=Scheinman|first2=Melvin M.|last3=Aliot|first3=Etienne M.|last4=Alpert|first4=Joseph S.|last5=Calkins|first5=Hugh|last6=Camm|first6=A. John|last7=Campbell|first7=W. Barton|last8=Haines|first8=David E.|last9=Kuck|first9=Karl H.|date=2003-10-14|title=ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias – executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Supraventricular Arrhythmias)|journal=Circulation|volume=108|issue=15|pages=1871–1909|doi=10.1161/01.CIR.0000091380.04100.84|issn=1524-4539|pmid=14557344|doi-access=free}}</ref>

==== Pericardial disease ====<!-- Pericardium-->
The sac which surrounds the heart, called the pericardium, can become inflamed in a condition known as [[pericarditis]]. This condition typically causes chest pain that may spread to the back, and is often caused by a viral infection ([[Infectious mononucleosis|glandular fever]], [[cytomegalovirus]], or [[coxsackievirus]]). Fluid can build up within the pericardial sac, referred to as a [[pericardial effusion]]. Pericardial effusions often occur secondary to pericarditis, kidney failure, or tumours, and frequently do not cause any symptoms. However, large effusions or effusions which accumulate rapidly can compress the heart in a condition known as [[cardiac tamponade]], causing breathlessness and potentially fatal low blood pressure. Fluid can be removed from the pericardial space for diagnosis or to relieve tamponade using a syringe in a procedure called [[pericardiocentesis]].{{sfn|Davidson's|2010|pp=638–639}}

==== Congenital heart disease ====<!--Congenital disease-->
{{main|Congenital heart defect}}
Some people are born with hearts that are abnormal and these abnormalities are known as congenital heart defects. They may range from the relatively minor (e.g. [[patent foramen ovale]], arguably a variant of normal) to serious life-threatening abnormalities (e.g. [[hypoplastic left heart syndrome]]). Common abnormalities include those that affect the heart muscle that separates the two side of the heart (a "hole in the heart", e.g. [[ventricular septal defect]]). Other defects include those affecting the heart valves (e.g. [[Aortic stenosis|congenital aortic stenosis]]), or the main blood vessels that lead from the heart (e.g. [[coarctation of the aorta]]). More complex syndromes are seen that affect more than one part of the heart (e.g. [[Tetralogy of Fallot]]).

Some congenital heart defects allow blood that is low in oxygen that would normally be returned to the lungs to instead be pumped back to the rest of the body. These are known as [[Cyanotic heart defect|cyanotic congenital heart defects]] and are often more serious. Major congenital heart defects are often picked up in childhood, shortly after birth, or even before a child is born (e.g. [[Transposition of the great vessels|transposition of the great arteries]]), causing breathlessness and a lower rate of growth. More minor forms of congenital heart disease may remain undetected for many years and only reveal themselves in adult life (e.g., [[atrial septal defect]]).<ref>{{Cite journal|last1=Baumgartner|first1=Helmut|last2=Bonhoeffer|first2=Philipp|last3=De Groot|first3=Natasja M.S.|last4=de Haan|first4=Fokko|last5=Deanfield|first5=John Erik|last6=Galie|first6=Nazzareno|last7=Gatzoulis|first7=Michael A.|last8=Gohlke-Baerwolf|first8=Christa|last9=Kaemmerer|first9=Harald|date=December 2010|title=ESC Guidelines for the management of grown-up congenital heart disease (new version 2010)|journal=European Heart Journal|volume=31|issue=23|pages=2915–2957|doi=10.1093/eurheartj/ehq249|issn=1522-9645|pmid=20801927|doi-access=free}}</ref>{{sfn|Harrison's|2011|p=1458–65}}

==== Channelopathies ====
{{main|Channelopathy}}
[[Channelopathies]] can be categorized based on the organ system they affect. In the cardiovascular system, the electrical impulse required for each heart beat is provided by the [[electrochemical gradient]] of each heart cell. Because the beating of the heart depends on the proper movement of ions across the surface membrane, cardiac ion channelopathies form a major group of heart diseases.<ref>{{Cite journal |last=Marbán |first=Eduardo |date=2002-01-10 |title=Cardiac channelopathies |url=https://pubmed.ncbi.nlm.nih.gov/11805845/ |journal=Nature |volume=415 |issue=6868 |pages=213–218 |doi=10.1038/415213a |issn=0028-0836 |pmid=11805845|bibcode=2002Natur.415..213M |s2cid=4419017 }}</ref><ref>{{Cite journal |last=Marban |first=Eduardo |date=2003-07-01 |title=Cardiac Channelopathies |url=https://www.heartviews.org/article.asp?issn=1995-705X;year=2003;volume=4;issue=3;spage=4;epage=4;aulast=Marban;type=0 |journal=Heart Views |language=en |volume=4 |issue=3 |page=4 |issn=1995-705X}}</ref> Cardiac ion channelopathies may explain some of the cases of [[sudden death syndrome]] and [[sudden arrhythmic death syndrome]].<ref name="Skinner">{{cite journal |vauthors=Skinner JR, Winbo A, Abrams D, Vohra J, Wilde AA |title=Channelopathies That Lead to Sudden Cardiac Death: Clinical and Genetic Aspects |journal=Heart Lung Circ |volume=28 |issue=1 |pages=22–30 |date=January 2019 |pmid=30389366 |doi=10.1016/j.hlc.2018.09.007 |s2cid=53270374 |url=}}</ref> Long QT syndrome is the most common form of cardiac channelopathy.

* [[Long QT syndrome]] (LQTS) – Mostly hereditary. On EKG can be observed as longer corrected QT interval (QTc). Characterized by fainting, sudden, life-threatening heart rhythm disturbances – [[Torsades de pointes]] type ventricular tachycardia, ventricular fibrillation and risk of sudden cardiac death.<ref>{{Cite web |title=Long QT Syndrome |url=https://rarediseases.org/rare-diseases/romano-ward-syndrome/ |access-date=2022-11-19 |website=NORD (National Organization for Rare Disorders) |language=en-US}}</ref>
* [[Short QT syndrome]].
* [[Catecholaminergic polymorphic ventricular tachycardia]] (CPVT).<ref>{{Cite web |title=Catecholaminergic polymorphic ventricular tachycardia: MedlinePlus Genetics |url=https://medlineplus.gov/genetics/condition/catecholaminergic-polymorphic-ventricular-tachycardia/ |access-date=2022-11-19 |website=medlineplus.gov |language=en}}</ref>
* [[Progressive cardiac conduction defect]] (PCCD).<ref>{{Cite web |title=Progressive familial heart block: MedlinePlus Genetics |url=https://medlineplus.gov/genetics/condition/progressive-familial-heart-block/ |access-date=2022-11-19 |website=medlineplus.gov |language=en}}</ref>
* [[Benign early repolarization|Early repolarisation syndrome]] (BER) – common in younger and active people, especially men, because it is affected by higher [[testosterone]] levels, which cause increased potassium currents, which further causes an elevation of the [[J-point]] on the EKG. In very rare cases, it can lead to ventricular fibrillation and death.<ref>{{Cite journal |last1=Bourier |first1=Felix |last2=Denis |first2=Arnaud |last3=Cheniti |first3=Ghassen |last4=Lam |first4=Anna |last5=Vlachos |first5=Konstantinos |last6=Takigawa |first6=Masateru |last7=Kitamura |first7=Takeshi |last8=Frontera |first8=Antonio |last9=Duchateau |first9=Josselin |last10=Pambrun |first10=Thomas |last11=Klotz |first11=Nicolas |last12=Derval |first12=Nicolas |last13=Sacher |first13=Frédéric |last14=Jais |first14=Pierre |last15=Haissaguerre |first15=Michel |date=2018-11-27 |title=Early Repolarization Syndrome: Diagnostic and Therapeutic Approach |journal=Frontiers in Cardiovascular Medicine |volume=5 |page=169 |doi=10.3389/fcvm.2018.00169 |issn=2297-055X |pmc=6278243 |pmid=30542653|doi-access=free }}</ref>
* [[Brugada syndrome]] – a genetic disorder characterized by an abnormal EKG and is one of the most common causes of sudden cardiac death in young men.<ref>{{Cite web |title=Brugada syndrome: MedlinePlus Genetics |url=https://medlineplus.gov/genetics/condition/brugada-syndrome/ |access-date=2022-11-19 |website=medlineplus.gov |language=en}}</ref>