Editing Cardiac arrest (section)

====Structural heart disease====
[[File:Heart left ventricular hypertrophy sa.jpg|thumb|Short axis view of the heart demonstrating wall thickening in left ventricular hypertrophy]]
Examples of structural heart diseases include: [[cardiomyopathy|cardiomyopathies]] ([[hypertrophic cardiomyopathy|hypertrophic]], [[dilated cardiomyopathy|dilated]], or [[Arrhythmogenic cardiomyopathy|arrhythmogenic]]), [[Cardiac arrhythmia|cardiac rhythm disturbances]], [[myocarditis]], and [[congestive heart failure]].<ref name="Kannel-1998">{{cite journal | vauthors = Kannel WB, Wilson PW, D'Agostino RB, Cobb J | title = Sudden coronary death in women | journal = American Heart Journal | volume = 136 | issue = 2 | pages = 205–212 | date = August 1998 | pmid = 9704680 | doi = 10.1053/hj.1998.v136.90226 }}</ref>
[[File:Left Ventricular Hypertrophy Unlabeled.jpg|thumb|EKG depiction of left ventricular hypertrophy]]
[[Left ventricular hypertrophy]] is a leading cause of sudden cardiac deaths in the adult population.<ref>{{cite journal | vauthors = Stevens SM, Reinier K, Chugh SS | title = Increased left ventricular mass as a predictor of sudden cardiac death: is it time to put it to the test? | journal = Circulation: Arrhythmia and Electrophysiology | volume = 6 | issue = 1 | pages = 212–217 | date = February 2013 | pmid = 23424223 | pmc = 3596001 | doi = 10.1161/CIRCEP.112.974931 }}</ref><ref name="Walls-2017" /> This is most commonly the result of longstanding [[Hypertension|high blood pressure]], or hypertension, which has led to maladaptive overgrowth of muscular tissue of the [[Ventricle (heart)|left ventricle]], the heart's main pumping chamber.<ref name="Katholi-2011">{{cite journal | vauthors = Katholi RE, Couri DM | title = Left ventricular hypertrophy: major risk factor in patients with hypertension: update and practical clinical applications | journal = International Journal of Hypertension | volume = 2011 | pages = 495349 | year = 2011 | pmid = 21755036 | pmc = 3132610 | doi = 10.4061/2011/495349 | doi-access = free }}</ref> This is because elevated blood pressure over the course of several years requires the heart to adapt to the requirement of pumping harder to adequately circulate blood throughout the body. If the heart does this for a prolonged period of time, the left ventricle can experience hypertrophy (grow larger) in a way that decreases the heart's effectiveness.<ref>{{cite book | vauthors = Bornstein AB, Rao SS, Marwaha K | chapter = Left Ventricular Hypertrophy |date=2021| chapter-url= http://www.ncbi.nlm.nih.gov/books/NBK557534/ | title = StatPearls|place=Treasure Island (FL) |publisher= StatPearls Publishing|pmid=32491466|access-date=2021-11-05 }}</ref> Left ventricular hypertrophy can be demonstrated on an [[Echocardiography|echocardiogram]] and [[Electrocardiography|electrocardiogram]] (EKG).<ref name="Katholi-2011" />

Abnormalities of the cardiac conduction system (notably the [[atrioventricular node]] and [[Purkinje fibers|His-Purkinje]] system) may predispose an individual to arrhythmias with a risk of progressing to sudden cardiac arrest, albeit this risk remains low. Many of these conduction blocks can be treated with internal cardiac defibrillators for those determined to be at high risk due to severity of fibrosis or severe electrophysiologic disturbances.<ref name="Saunders-2015" />

Structural heart diseases unrelated to coronary artery disease account for 10% of all sudden cardiac deaths.<ref name="Podrid-2016" /><ref name="Zheng-2001" /> A 1999 review of sudden cardiac deaths in the United States found that structural heart diseases accounted for over 30% of sudden cardiac arrests for those under 30 years.<ref name="CDC-2002" /><ref name="Zheng-2001" />