Title: Hypertrophic cardiomyopathy

{{Short description|Enlargement of the heart muscle}}
{{Redirect|HOCM|the museum in Olympia, Washington, US|Hands On Children's Museum}}
{{Use dmy dates|date=December 2025}}
{{cs1 config|name-list-style=vanc|display-authors=6}}
{{Infobox medical condition
| name            = Hypertrophic cardiomyopathy
| synonyms        = Asymmetric septal hypertrophy; idiopathic hypertrophic subaortic stenosis;&lt;ref&gt;{{cite web|title=Other Names for Cardiomyopathy|url=http://www.nhlbi.nih.gov/health/health-topics/topics/cm/names|website=NHLBI|access-date=31 August 2016|date=22 June 2016|archive-url=https://web.archive.org/web/20160728023504/http://www.nhlbi.nih.gov/health/health-topics/topics/cm/names|archive-date=28 July 2016}}&lt;/ref&gt; hypertrophic obstructive cardiomyopathy (HOCM)
| image           = Hypertrophic obstructive cardiomyopathy.png
| image_size      = 220px
| field           = [[Cardiology]]
| symptoms        = Feeling tired, [[pedal edema|leg swelling]], [[shortness of breath]], [[chest pain]], [[syncope (medicine)|fainting]]&lt;ref name=NIH2016Sym/&gt;
| complications   = [[Heart failure]], [[Heart arrhythmia|irregular heartbeat]], [[sudden cardiac death]]&lt;ref name=NIH2016What/&gt;&lt;ref name=SCD2011/&gt;
| onset           =
| duration        =
| types           =
| causes          = [[Genetics]], [[Fabry disease]], [[Friedreich's ataxia]], certain medications&lt;ref name=Fer2018/&gt;&lt;ref name=NIH2016Ca/&gt;
| risks           =
| diagnosis       = [[Electrocardiogram]], [[echocardiogram]], [[stress testing]], [[genetic testing]]&lt;ref name=JACC2011/&gt;
| differential    = [[Hypertensive heart disease]], [[aortic stenosis]], [[athlete's heart]]&lt;ref name=Fer2018/&gt;
| prevention      =
| treatment       = Medications, [[implantable cardiac defibrillator]], surgery&lt;ref name=JACC2011/&gt;
| medication      = [[Beta blockers]], [[verapamil]], [[disopyramide]]&lt;ref name=Raja2020/&gt;
| prognosis       = Less than 1% per year risk of death (with treatment)&lt;ref name=Mar2014/&gt;
| frequency       = in average 1 in 500 people&lt;ref name=Raja2020/&gt;
| deaths          =
}}
&lt;!-- Definition and symptoms --&gt;
'''Hypertrophic cardiomyopathy''' ('''HCM''', or '''HOCM''' when [[#Variants|obstructive]]) is a condition in which [[muscle|muscle tissues]] of the [[heart]] become [[hypertrophy|thickened]] without an obvious cause.&lt;ref name=Raja2020&gt;{{cite book | vauthors = Cui H, Schaff HV | veditors =Raja SG |title=Cardiac Surgery: A Complete Guide |date=2020 |publisher=Springer |location=Switzerland |isbn=978-3-030-24176-6 |pages=735–748 |chapter-url=https://books.google.com/books?id=kcPPDwAAQBAJ&amp;pg=PA735 |language=en |chapter=80. Hypertrophic cardiomyopathy |access-date=20 October 2022 |archive-date=10 January 2023 |archive-url=https://web.archive.org/web/20230110100927/https://books.google.com/books?id=kcPPDwAAQBAJ&amp;pg=PA735 |url-status=live }}&lt;/ref&gt; The parts of the heart most commonly affected are the [[interventricular septum]] and the [[Ventricular hypertrophy|ventricles]].&lt;ref name=&quot;:0&quot;&gt;{{cite book | vauthors = Basit H, Brito D, Sharma S | chapter =Hypertrophic Cardiomyopathy|date=2020| chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK430788/| title =StatPearls|place=Treasure Island (FL)|publisher=StatPearls Publishing|pmid=28613539|access-date=20 September 2020 |archive-date=6 April 2021|archive-url= https://web.archive.org/web/20210406104824/https://www.ncbi.nlm.nih.gov/books/NBK430788/ |url-status=live}}&lt;/ref&gt; This results in the heart being less able to pump [[blood]] effectively and also may cause [[Cardiac conduction system|electrical conduction]] problems.&lt;ref name=NIH2016What&gt;{{cite web|title=What Is Cardiomyopathy?|url=https://www.nhlbi.nih.gov/health/cardiomyopathy|website=NHLBI|access-date=10 November 2017|date=22 June 2016|archive-url=https://web.archive.org/web/20171110172002/https://www.nhlbi.nih.gov/health/health-topics/topics/cm|archive-date=10 November 2017|url-status=live}}&lt;/ref&gt; Specifically affected are the [[bundle branches]] that conduct impulses through the interventricular septum and into the [[Purkinje fibers]], as these are responsible for the [[depolarization]] of contractile cells of both ventricles.&lt;ref name=NIH2023&gt;{{cite journal | vauthors = Bernardini A, Crotti L, Olivotto I, Cecchi F | title = Diagnostic and prognostic electrocardiographic features in patients with hypertrophic cardiomyopathy | journal = European Heart Journal Supplements | volume = 25 | issue = Suppl C | pages = C173–C178 | date = May 2023 | pmid = 37125268 | pmc = 10132576 | doi = 10.1093/eurheartjsupp/suad074 }}&lt;/ref&gt;

People who have hypertrophic cardiomyopathy may have a range of symptoms. People may be asymptomatic, or may have [[fatigue]], [[pedal edema|leg swelling]], and [[shortness of breath]].&lt;ref name=&quot;NIH2016Sym&quot; /&gt; It may also result in [[chest pain]] or [[syncope (medicine)|fainting]].&lt;ref name=&quot;NIH2016Sym&quot;&gt;{{cite web|title=What Are the Signs and Symptoms of Cardiomyopathy?|url=https://www.nhlbi.nih.gov/health/cardiomyopathy/symptoms|website=NHLBI|access-date=10 November 2017|date=22 June 2016|archive-url=https://web.archive.org/web/20160728023343/http://www.nhlbi.nih.gov/health/health-topics/topics/cm/signs|archive-date=28 July 2016|url-status=live}}&lt;/ref&gt; Symptoms may be worse when the person is dehydrated.&lt;ref name=&quot;:0&quot; /&gt; Complications may include [[heart failure]], an [[Heart arrhythmia|irregular heartbeat]], and [[sudden cardiac death]].&lt;ref name=&quot;NIH2016What&quot; /&gt;&lt;ref name=&quot;SCD2011&quot;&gt;{{cite journal | vauthors = Barsheshet A, Brenyo A, Moss AJ, Goldenberg I | title = Genetics of sudden cardiac death | journal = Current Cardiology Reports | volume = 13 | issue = 5 | pages = 364–376 | date = October 2011 | pmid = 21789574 | doi = 10.1007/s11886-011-0209-y | s2cid = 25887172 }}&lt;/ref&gt;

Hypertrophic cardiomyopathy is most commonly [[heredity|inherited]] in an [[Dominance_(genetics)|autosomal dominant pattern]].&lt;ref name=&quot;NIH2016Ca&quot;&gt;{{cite web|title=What Causes Cardiomyopathy?|url=https://www.nhlbi.nih.gov/health/cardiomyopathy/causes|website=NHLBI|access-date=10 November 2017|date=22 June 2016|archive-url=https://web.archive.org/web/20171005114628/https://www.nhlbi.nih.gov/health/health-topics/topics/cm/causes|archive-date=5 October 2017|url-status=live}}&lt;/ref&gt;&lt;ref name=&quot;:0&quot; /&gt; It is often due to [[mutation]]s in certain [[genes]] involved with making [[heart muscle]] proteins.&lt;ref name=&quot;NIH2016Ca&quot; /&gt; Other inherited causes of left ventricular hypertrophy include [[Fabry disease]] and [[Friedreich's ataxia]].&lt;ref name=&quot;Fer2018&quot;&gt;{{cite book| vauthors = Ferri FF |title=Ferri's Clinical Advisor 2018 E-Book: 5 Books in 1|date=2017|publisher=Elsevier Health Sciences|isbn=978-0-323-52957-0|page=246|url=https://books.google.com/books?id=wGclDwAAQBAJ&amp;pg=PA246|access-date=10 November 2017|archive-url=https://web.archive.org/web/20171110225010/https://books.google.ca/books?id=wGclDwAAQBAJ&amp;pg=PA246|archive-date=10 November 2017|url-status=live}}&lt;/ref&gt; Other considerations for causes of enlarged heart are [[Athletic heart syndrome|athlete's heart]] and [[hypertension]] (high blood pressure).&lt;ref name=&quot;:0&quot; /&gt; Making the diagnosis of hypertrophic cardiomyopathy often involves a family history or [[Genetic genealogy|pedigree]], an [[electrocardiogram]], [[echocardiogram]], and [[stress testing]].&lt;ref name=&quot;JACC2011&quot; /&gt; [[Genetic testing]] is recommended for affected people and their family members.&lt;ref name=&quot;Braunwald 2025&quot; /&gt;&lt;ref name=&quot;JACC2011&quot;&gt;{{cite journal | vauthors = Gersh BJ, Maron BJ, Bonow RO, Dearani JA, Fifer MA, Link MS, Naidu SS, Nishimura RA, Ommen SR, Rakowski H, Seidman CE, Towbin JA, Udelson JE, Yancy CW | title = 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines | journal = The Journal of Thoracic and Cardiovascular Surgery | volume = 142 | issue = 6 | pages = 1303–1338 | date = December 2011 | pmid = 22093712 | doi = 10.1016/j.jtcvs.2011.10.019 | doi-access = free }}&lt;/ref&gt; Hypertrophic cardiomyopathy can be distinguished from other inherited causes of cardiomyopathy by its autosomal dominant pattern, whereas Fabry disease is X-linked, and Friedreich's ataxia is inherited in an autosomal recessive pattern.&lt;ref name=&quot;:0&quot; /&gt;

&lt;!-- Treatment and prognosis --&gt;
Treatment depends on symptoms and other risk factors. Medications may include [[beta blockers]], [[verapamil]] or [[disopyramide]].&lt;ref name=Raja2020/&gt; An [[implantable cardiac defibrillator]] may be recommended in those with certain types of irregular heartbeat.&lt;ref name=&quot;JACC2011&quot; /&gt; Surgery, in the form of a [[septal myectomy]] or [[heart transplant]], may be done in those who do not improve with other measures.&lt;ref name=&quot;JACC2011&quot; /&gt; With treatment, the risk of death from the disease is less than one percent per year.&lt;ref name=&quot;Mar2014&quot;&gt;{{cite journal | vauthors = Maron BJ, Ommen SR, Semsarian C, Spirito P, Olivotto I, Maron MS | title = Hypertrophic cardiomyopathy: present and future, with translation into contemporary cardiovascular medicine | journal = Journal of the American College of Cardiology | volume = 64 | issue = 1 | pages = 83–99 | date = July 2014 | pmid = 24998133 | doi = 10.1016/j.jacc.2014.05.003 | doi-access =  }}&lt;/ref&gt;

&lt;!-- Epidemiology and history --&gt;
Hypertrophic cardiomyopathy affects up to one in 500 people.&lt;ref name=Raja2020/&gt; People of all ages may be affected.&lt;ref name=NIH2016Type&gt;{{cite web|title=Types of Cardiomyopathy|url=https://www.nhlbi.nih.gov/health/cardiomyopathy|website=NHLBI|access-date=10 November 2017|date=22 June 2016|archive-url=https://web.archive.org/web/20171004214624/https://www.nhlbi.nih.gov/health/health-topics/topics/cm/types|archive-date=4 October 2017|url-status=live}}&lt;/ref&gt; The first modern description of the disease was by [[Donald Teare]] in 1958.&lt;ref&gt;{{cite journal | vauthors = Teare D | title = Asymmetrical hypertrophy of the heart in young adults | journal = British Heart Journal | volume = 20 | issue = 1 | pages = 1–8 | date = January 1958 | pmid = 13499764 | pmc = 492780 | doi = 10.1136/hrt.20.1.1 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = McKenna WJ, Sen-Chowdhry S | title = From Teare to the present day: a fifty year odyssey in hypertrophic cardiomyopathy, a paradigm for the logic of the discovery process | journal = Revista Espanola de Cardiologia | volume = 61 | issue = 12 | pages = 1239–1244 | date = December 2008 | pmid = 19080961 | doi = 10.1016/S1885-5857(09)60050-5 | url = http://www.revespcardiol.org/en/from-teare-to-the-present/articulo/13130628/ | access-date = 6 February 2017 | url-status = live | archive-url = https://web.archive.org/web/20171111041703/http://www.revespcardiol.org/en/from-teare-to-the-present/articulo/13130628/ | archive-date = 11 November 2017 | url-access = subscription }}&lt;/ref&gt;

== Signs and symptoms ==
Many people with hypertrophic cardiomyopathy are asymptomatic or mildly symptomatic, and many of those carrying disease genes for hypertrophic cardiomyopathy do not have clinically detectable disease.&lt;ref name=&quot;Mar2002&quot;/&gt; The [[symptom]]s of hypertrophic cardiomyopathy include shortness of breath due to stiffening and decreased blood filling of the ventricles, exertional chest pain (also known as [[Angina pectoris|angina]]) due to reduced blood flow to the coronary arteries, uncomfortable awareness of the [[Cardiac cycle|heart beat]] ([[palpitations]]), [[lightheadedness]], weakness, [[Syncope (medicine)|fainting]] and [[sudden cardiac death]].&lt;ref&gt;{{cite journal | vauthors = Fifer MA, Vlahakes GJ | title = Management of symptoms in hypertrophic cardiomyopathy | journal = Circulation | volume = 117 | issue = 3 | pages = 429–439 | date = January 2008 | pmid = 18212300 | doi = 10.1161/CIRCULATIONAHA.107.694158 | doi-access = free }}&lt;/ref&gt;&lt;ref name=&quot;:1&quot;&gt;{{cite book | vauthors = Basit H, Brito D, Sharma S | chapter = Hypertrophic Cardiomyopathy |date=2023 | chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK430788/ | title = StatPearls |access-date=25 October 2023 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=28613539 }}&lt;/ref&gt;

[[Dyspnea|Shortness of breath]] is largely due to increased thickness of the [[left ventricle]] (LV) wall and interventricular septal wall, which impairs the filling of the ventricles, but also leads to elevated pressure in the left ventricle and left atrium as a result of increased thickness. This impaired heart filling can cause blood to back up in the lungs' circulation, causing further symptoms&lt;ref name=&quot;Braunwauld 2005&quot;&gt;{{cite book |chapter=The Cardiomyopathies |vauthors=Bonow R, Braunwald E, Zipes DP, Libby P |title=Braunwald's heart disease: a textbook of cardiovascular medicine |chapter-url=https://archive.org/details/braunwaldsheartd0000unse_n3o8 |chapter-url-access=registration |publisher=WB Saunders |location=Philadelphia |year=2005 |edition=7th |isbn=978-1-4160-0014-3 }}&lt;/ref&gt; Often, symptoms of hypertrophic cardiomyopathy are due to [[congestive heart failure]] (especially activity intolerance and dyspnea), but also lower extremity [[edema]].&lt;ref name=&quot;Braunwald 2025&quot; /&gt;

Major risk factors for sudden death in individuals with hypertrophic cardiomyopathy include prior history of [[cardiac arrest]] or [[ventricular fibrillation]], spontaneous sustained [[ventricular tachycardia]], abnormal exercise blood pressure and non-sustained ventricular tachycardia, unexplained [[syncope (medicine)|syncope]], family history of premature sudden death, and left ventricular wall thickness greater than 15&amp;nbsp;mm to 30&amp;nbsp;mm, on echocardiogram.&lt;ref name=&quot;Maron, McKenna et al. 2003&quot;&gt;{{cite journal | vauthors = Maron BJ, McKenna WJ, Danielson GK, Kappenberger LJ, Kuhn HJ, Seidman CE, Shah PM, Spencer WH, Spirito P, Ten Cate FJ, Wigle ED | title = American College of Cardiology/European Society of Cardiology clinical expert consensus document on hypertrophic cardiomyopathy. A report of the American College of Cardiology Foundation Task Force on Clinical Expert Consensus Documents and the European Society of Cardiology Committee for Practice Guidelines | journal = Journal of the American College of Cardiology | volume = 42 | issue = 9 | pages = 1687–1713 | date = November 2003 | pmid = 14607462 | doi = 10.1016/S0735-1097(03)00941-0 | doi-access = free }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Kalyva A, Parthenakis FI, Marketou ME, Kontaraki JE, Vardas PE | title = Biochemical characterisation of Troponin C mutations causing hypertrophic and dilated cardiomyopathies | journal = Journal of Muscle Research and Cell Motility | volume = 35 | issue = 2 | pages = 161–178 | date = April 2014 | pmid = 24744096 | doi = 10.1007/s10974-014-9382-0 | s2cid = 1726747 }}&lt;/ref&gt;

Hypertrophic cardiomyopathy also presents with a [[Systole|systolic]] ejection [[Heart murmur|murmur]] that increases in intensity with decreased [[Preload (cardiology)|preload]] (as in the [[Valsalva maneuver]] or standing), or with decreased [[afterload]] (as in vasodilator administration). On the other hand, the murmur decreases in intensity with increased preload (as in squatting) or increased afterload (as in the [[handgrip maneuver]]).&lt;ref name=&quot;:1&quot; /&gt; &quot;Spike and dome&quot; pulse and &quot;triple ripple [[apical impulse]]&quot; are two other signs that can be discovered in physical examination.&lt;ref&gt;{{cite book | vauthors = Murphy JG, Lloyd MA |title=Mayo Clinic Cardiology Concise Textbook and Mayo Clinic Cardiology Board Review Questions &amp; Answers: (TEXT AND Q&amp;A SET) |date=2007 |publisher=CRC Press |isbn=978-1-4398-2545-7 |page=1159 |url=https://books.google.com/books?id=CJVsBgAAQBAJ&amp;pg=PA1159 |access-date=22 October 2018 |archive-url=https://web.archive.org/web/20181023034755/https://books.google.ca/books?id=CJVsBgAAQBAJ&amp;pg=PA1159 |archive-date=23 October 2018 |url-status=live }}&lt;/ref&gt; [[Pulsus bisferiens]] may also be found during examination.&lt;ref&gt;{{cite book | vauthors = Sievert H, Qureshi SA, Wilson N, Hijazi ZM  |url=https://books.google.com/books?id=AqPNBQAAQBAJ&amp;pg=PA46 |title=Interventions in Structural, Valvular and Congenital Heart Disease |date=2015 |publisher=CRC Press |isbn=978-1-4822-1564-9 |edition=second |page=46 |access-date=2 January 2018 |archive-url=https://web.archive.org/web/20180103073947/https://books.google.ca/books?id=AqPNBQAAQBAJ&amp;pg=PA46 |archive-date=3 January 2018 |url-status=live }}&lt;/ref&gt;

==Genetics==
{| class=&quot;wikitable&quot; style=&quot;float: right; margin-left:15px; text-align:center&quot;
|+Genetic basis
|-
! Gene
! Locus
! Type
|-
| [[MYH7]]
| 14q12
| CMH1 ({{OMIM|192600||none}})
|-
| [[TNNT2]]
| 1q32
| CMH2 ({{OMIM|115195||none}})
|-
| [[TPM1]]
| 15q22.1
| CMH3 ({{OMIM|115196||none}})
|-
| [[MYBPC3]]
| 11p11.2
| CMH4 ({{OMIM|115197||none}})
|-
| ?
| ?
| CMH5
|-
| [[PRKAG2]]
| 7q36
| CMH6 ({{OMIM|600858||none}})
|-
| [[TNNI3]]
| 19q13.4
| CMH7 ({{OMIM|613690||none}})
|-
| [[MYL3]]
| 3p
| CMH8 ({{OMIM|608751||none}})
|-
| [[Titin|TTN]]
| 2q24.3
| CMH9 ({{OMIM|613765||none}})
|-
| [[MYL2]]
| 12q23-q24
| CMH10 ({{OMIM|608758||none}})
|-
| [[ACTC1]]
| 15q14
| CMH11 ({{OMIM|612098||none}})
|-
| [[CSRP3]]
| 11p15.1
| CMH12 ({{OMIM|612124||none}})
|}
Familial hypertrophic cardiomyopathy is inherited as an [[autosomal dominant]] trait which is attributed to mutations in one of several [[gene]]s that encode for the [[sarcomere]] [[protein]]s, and most diagnosed individuals will have an affected parent. Occasionally, both copies of the gene will be defective, a condition that may lead to a more severe manifestation of the disease.&lt;ref&gt;{{cite journal | vauthors = Chahine RA, Raizner AF, Luchi RJ | title = The genetics and semantics of hypertrophic cardiomyopathy | journal = Chest | volume = 74 | issue = 6 | pages = 695–696 | date = December 1978 | doi = 10.1378/chest.74.6.695-a | pmid = 738133 | url = https://journal.chestnet.org/article/S0012-3692(15)45522-9/fulltext | access-date = 2 April 2023 | url-status = live | archive-url = https://web.archive.org/web/20230809062440/https://journal.chestnet.org/article/S0012-3692%2815%2945522-9/fulltext | archive-date = 9 August 2023 | url-access = subscription }}&lt;/ref&gt;&lt;ref name=&quot;:0&quot; /&gt;

Currently, about 40–60% of people with hypertrophic cardiomyopathy will have a mutation identified in at least one of nine sarcomeric genes.&lt;ref name=&quot;Braunwald 2025&quot; /&gt; Approximately 40% of these mutations occur in the β-[[myosin heavy chain]] gene on [[chromosome 14]] q11.2-3, and approximately 40% involve the cardiac [[MYBPC3|myosin-binding protein C]] gene. Since hypertrophic cardiomyopathy is typically an [[autosomal dominant]] trait, children of a single hypertrophic cardiomyopathy parent have a 50% chance of inheriting the disease-causing mutation. Whenever such a mutation is identified, family-specific genetic testing can be used to identify relatives at risk for the disease, although clinical severity and age of onset cannot be predicted.&lt;ref&gt;{{cite book |vauthors=Cirino AL, Ho C |chapter=Hypertrophic Cardiomyopathy Overview |veditors=Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJ, Stephens K, Amemiya A |year=2014 |title=GeneReviews |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK1768/ |publisher=University of Washington, Seattle |pmid=20301725 |access-date=11 February 2017 |archive-date=18 January 2017 |archive-url=https://web.archive.org/web/20170118125341/https://www.ncbi.nlm.nih.gov/books/NBK1768/ |url-status=live }}&lt;/ref&gt;[[File:Cardiac sarcomere structure.png|thumb|308x308px|Cardiac sarcomere structure, featuring various components, including myosin-binding protein C]]An insertion/deletion polymorphism in the gene encoding for [[angiotensin converting enzyme]] (ACE) alters the clinical [[phenotype]] of the disease. The D/D (deletion/deletion) genotype of ACE is associated with more marked hypertrophy of the left ventricle and may be associated with a higher risk of adverse outcomes.&lt;ref name=&quot;Doolan, Nguyen et al. 2004&quot;&gt;{{cite journal | vauthors = Doolan G, Nguyen L, Chung J, Ingles J, Semsarian C | title = Progression of left ventricular hypertrophy and the angiotensin-converting enzyme gene polymorphism in hypertrophic cardiomyopathy | journal = International Journal of Cardiology | volume = 96 | issue = 2 | pages = 157–163 | date = August 2004 | pmid = 15314809 | doi = 10.1016/j.ijcard.2004.05.003 }}&lt;/ref&gt;&lt;ref name=&quot;Marian, Yu et al. 1993&quot;&gt;{{cite journal | vauthors = Marian AJ, Yu QT, Workman R, Greve G, Roberts R | title = Angiotensin-converting enzyme polymorphism in hypertrophic cardiomyopathy and sudden cardiac death | journal = Lancet | volume = 342 | issue = 8879 | pages = 1085–1086 | date = October 1993 | pmid = 8105312 | doi = 10.1016/0140-6736(93)92064-Z | s2cid = 39088276 }}&lt;/ref&gt;

Over 1400 mutations have been identified in genes known to lead to hypertrophic cardiomyopathy.&lt;ref&gt;{{cite journal | vauthors = Maron BJ, Maron MS | title = Hypertrophic cardiomyopathy | journal = Lancet | volume = 381 | issue = 9862 | pages = 242–255 | date = January 2013 | pmid = 22874472 | doi = 10.1016/s0140-6736(12)60397-3 | s2cid = 38333896 }}&lt;/ref&gt; Some mutations could have more harmful potential compared to others (β-myosin heavy chain). For example, [[TNNT2|troponin T]] mutations were originally associated with a 50% mortality before the age of 40. However, a more recent and larger study found a similar risk to other sarcomeric protein mutations.&lt;ref name=&quot;Pasquale et al. 2012&quot;&gt;{{cite journal | vauthors = Pasquale F, Syrris P, Kaski JP, Mogensen J, McKenna WJ, Elliott P | title = Long-term outcomes in hypertrophic cardiomyopathy caused by mutations in the cardiac troponin T gene | journal = Circulation: Cardiovascular Genetics | volume = 5 | issue = 1 | pages = 10–17 | date = February 2012 | pmid = 22144547 | doi = 10.1161/CIRCGENETICS.111.959973 | doi-access = free }}&lt;/ref&gt; The age at disease onset of hypertrophic cardiomyopathy with [[MYH7]] mutations is earlier and leads to more severe symptoms.&lt;ref name=&quot;Sedaghat-Hamedani F et al. 2017&quot;&gt;{{cite journal | vauthors = Sedaghat-Hamedani F, Kayvanpour E, Tugrul OF, Lai A, Amr A, Haas J, Proctor T, Ehlermann P, Jensen K, Katus HA, Meder B | title = Clinical outcomes associated with sarcomere mutations in hypertrophic cardiomyopathy: a meta-analysis on 7675 individuals | journal = Clinical Research in Cardiology | volume = 107 | issue = 1 | pages = 30–41 | date = January 2018 | pmid = 28840316 | doi = 10.1007/s00392-017-1155-5 | s2cid = 23723131 }}&lt;/ref&gt; Moreover, mutations on [[troponin C]] can alter Ca&lt;sup&gt;+2&lt;/sup&gt; sensibility on force development in cardiac muscle, these mutations are named after the amino acid that was changed after the location in which it happened, such as [[A8V]], A31S, C84Y and [[D145E]].&lt;ref&gt;{{cite journal | vauthors = Cheng Y, Regnier M | title = Cardiac troponin structure-function and the influence of hypertrophic cardiomyopathy associated mutations on modulation of contractility | journal = Archives of Biochemistry and Biophysics | volume = 601 | pages = 11–21 | date = July 2016 | pmid = 26851561 | pmc = 4899195 | doi = 10.1016/j.abb.2016.02.004 }}&lt;/ref&gt;

== Pathophysiology ==
Ventricular hypertrophy causes a dynamic pressure gradient across the left ventricular outflow tract (LVOT), which is associated with further narrowing of the outflow during [[systole]]. Pulling of the [[mitral valve]] leaflets towards the septum contributes to the outflow obstruction. This pulling is thought to occur by several proposed mechanisms, including the flow of blood through the narrowed outflow tract resulting in a higher velocity, and less pressure via the [[Venturi effect]].&lt;ref name=&quot;:1&quot; /&gt; This low pressure then causes the anterior leaflet of the mitral valve to be pulled into the outflow tract, resulting in further obstruction.&lt;ref name=&quot;:2&quot;&gt;{{cite web |title=Venturi effect |url=https://www.healio.com/cardiology/learn-the-heart/cardiology-review/topic-reviews/venturi-effect |access-date=25 October 2023 |website=www.healio.com |language=en}}&lt;/ref&gt;

The hypertrophied (thickened) left ventricular wall in hypertrophic cardiomyopathy requires a greater oxygen demand. This increased oxygen demand of the enlarged heart muscle, combined with fibrosis (scarring) of the heart muscle and a reduced flow through thick-walled [[coronary arteries]] results in an oxygen deficit to the heart muscle. These pathophysiological changes result in the anginal (exertional chest pain) symptoms sometimes seen in hypertrophic cardiomyopathy.&lt;ref name=&quot;Braunwald 2025&quot; /&gt;

== Diagnosis ==
[[File:DVA2555 (CardioNetworks ECGpedia).jpg|thumb|upright=1.6|An ECG showing HOCM]]

A [[medical diagnosis|diagnosis]] of hypertrophic cardiomyopathy is based upon several features of the disease process. While there is use of [[echocardiogram|echocardiography]], [[cardiac catheterization]], or [[cardiac MRI]] in the diagnosis of the disease, other important considerations include [[electrocardiogram|ECG]] and [[genetic testing]]. Genetic testing is recommended for those affected by hypertrophic cardiomyopathy and their family members.&lt;ref name=&quot;Braunwald 2025&quot; /&gt;
In about 60 to 70% of the cases, cardiac MRI shows thickening of more than 15&amp;nbsp;mm of the lower part of the ventricular septum. T1-weighted imaging may identify scarring of cardiac tissues while T2-weighted imaging may identify edema and inflammation of cardiac tissue which is associated with acute clinical signs of chest pain and fainting episodes.&lt;ref&gt;{{cite journal | vauthors = Amano Y, Kitamura M, Takano H, Yanagisawa F, Tachi M, Suzuki Y, Kumita S, Takayama M | title = Cardiac MR Imaging of Hypertrophic Cardiomyopathy: Techniques, Findings, and Clinical Relevance | journal = Magnetic Resonance in Medical Sciences | volume = 17 | issue = 2 | pages = 120–131 | date = April 2018 | pmid = 29343659 | pmc = 5891337 | doi = 10.2463/mrms.rev.2017-0145 }}&lt;/ref&gt;

ECG is the most sensitive diagnostic test.&lt;ref name=&quot;:1&quot; /&gt;

===Variants {{anchor|Obstructive and non-obstructive}}===
Depending on whether the distortion of normal heart anatomy causes an obstruction of the outflow of blood from the left ventricle of the heart, hypertrophic cardiomyopathy can be classified as obstructive or non-obstructive.&lt;ref name=&quot;pmid33215931&quot;&gt;{{cite journal | vauthors = Ommen SR, Mital S, Burke MA, Day SM, Deswal A, Elliott P, Evanovich LL, Hung J, Joglar JA, Kantor P, Kimmelstiel C, Kittleson M, Link MS, Maron MS, Martinez MW, Miyake CY, Schaff HV, Semsarian C, Sorajja P | title = 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines | journal = Circulation | volume = 142 | issue = 25 | pages = e558–e631 | date = December 2020 | pmid = 33215931 | doi = 10.1161/CIR.0000000000000937 | s2cid = 227078319 | doi-access = free }}&lt;/ref&gt; The obstructive variant of hypertrophic cardiomyopathy is hypertrophic obstructive cardiomyopathy (HOCM).&lt;ref&gt;{{cite book| vauthors = Kouchoukos N, Blackstone EH, Hanley FL, Kirklin JK |title= Kirklin/Barratt-Boyes Cardiac Surgery E-Book|publisher= Elsevier|year= 2013|url= https://bookshelf.health.elsevier.com/books/9780323247405|isbn= 978-1-4160-6391-9|edition= 4th|page= 770|access-date= 2 December 2022|archive-date= 9 August 2023|archive-url= https://web.archive.org/web/20230809062440/https://bookshelf.health.elsevier.com/|url-status= live}}&lt;/ref&gt; The diagnosis of left ventricular outflow tract obstruction is usually made by echocardiographic assessment and is defined as a peak left ventricular outflow tract gradient of ≥ 30 mmHg.&lt;ref name=&quot;pmid33215931&quot; /&gt;

Another, non-obstructive variant of hypertrophic cardiomyopathy is apical hypertrophic cardiomyopathy (AHCM or ApHCM),&lt;ref name=pmid8685759&gt;{{cite journal | vauthors = Rivera-Diaz J, Moosvi AR | title = Apical hypertrophic cardiomyopathy | journal = Southern Medical Journal | volume = 89 | issue = 7 | pages = 711–713 | date = July 1996 | pmid = 8685759 | doi = 10.1097/00007611-199607000-00012 }}&lt;/ref&gt; also called '''Yamaguchi syndrome'''. It was first described in individuals of [[Japan]]ese descent. Sakamoto was the first to report the condition's ECG pattern in 1976. Yamaguchi was the first to characterize the syndrome and its ventriculargrophic feature in 1979.&lt;ref&gt;Yamaguchi H, Ishimura T, Nishiyama S, Nagasaki F, Nakanishi S, Takatsu F, Nishijo T, Umeda T, Machii K. Hypertrophic nonobstructive cardiomyopathy with giant negative T waves (apical hypertrophy): ventriculographic and echocardiographic features in 30 patients. Am J Cardiol. 1979 Sep;44(3):401-12. doi: 10.1016/0002-9149(79)90388-6. PMID 573056.&lt;/ref&gt; Yamaguchi syndrome is an infrequent variant of hypertrophic cardiomyopathy in the European population. ApHCM is thought to be autosomal dominant, with the majority of mutations occurring in the genes encoding for the sarcomere.&lt;ref name=&quot;Arad 2005&quot;&gt;{{cite journal |last1=Arad |first1=Michael |last2=Penas-Lado |first2=Manual |last3=Monserrat |first3=Lorenzo |last4=Maron |first4=Barry J. |last5=Sherrid |first5=Mark |last6=Ho |first6=Carolyn Y. |last7=Barr |first7=Scott |last8=Karim |first8=Ahmad |last9=Olson |first9=Timothy M. |last10=Kamisago |first10=Mitsohiro |last11=Seidman |first11=J.G. |last12=Seidman |first12=Christine E. |title=Gene Mutations in Apical Hypertrophic Cardiomyopathy |journal=Circulation |date=November 2005 |volume=112 |issue=18 |pages=2805–2811 |doi=10.1161/circulationaha.105.547448}}&lt;/ref&gt; ECG findings in Yamaguchi syndrome may mimic those of a heart attack. Yamaguchi syndrome has a more favorable prognosis than classic hypertrophic cardiomyopathy, and it is more common in Asian populations.&lt;ref name=&quot;Dasari 2023&quot;&gt;{{cite journal |last1=Dasari |first1=Mahati |last2=Arun Kumar |first2=Pramukh |last3=Bhattad |first3=Pradnya Brijmohan |last4=Jha |first4=Anil |last5=Sherif |first5=Akil A. |last6=Mishra |first6=Ajay K. |last7=Ramsaran |first7=Eddison |title=Yamaguchi syndrome – An updated review article of electrocardiographic and echocardiographic findings |journal=The American Journal of the Medical Sciences |date=July 2023 |volume=366 |issue=1 |pages=27–31 |doi=10.1016/j.amjms.2023.03.025}}&lt;/ref&gt;

===Cardiac catheterization===
[[Image:Hypertrophic Cardiomyopathy - Intraventricular Pressure Tracing.png|thumb|Pressure tracings demonstrating the Brockenbrough–Braunwald–Morrow sign&lt;br /&gt;AO = Descending aorta; LV = Left ventricle; ECG = Electrocardiogram.&lt;br /&gt;After the third [[electrocardiogram|QRS complex]], the ventricle has more time to fill. Since there is more time to fill, the left ventricle will have more volume at the end of [[diastole]] (increased [[Preload (cardiology)|preload]]). Due to the [[Frank–Starling law of the heart]], the contraction of the left ventricle (and pressure generated by the left ventricle) will be greater on the subsequent beat (beat #4 in this picture). Because of the dynamic nature of the outflow obstruction in hypertrophic cardiomyopathy, the obstruction increases ''more'' than the left ventricular pressure increase. This causes a fall in the aortic pressure as the left ventricular pressure rises (seen as the yellow shaded area in the picture).]]

Upon [[cardiac catheterization]], [[catheter]]s can be placed in the left ventricle and the ascending [[aorta]], to measure the pressure difference between these structures. In normal individuals, during ventricular [[Systole (medicine)|systole]], the pressure in the ascending aorta and the left ventricle will equalize, and the aortic valve is open. In individuals with [[aortic stenosis]] or with hypertrophic cardiomyopathy with an outflow tract gradient, there will be a pressure gradient (difference) between the left ventricle and the aorta, with the left ventricular pressure higher than the aortic pressure. This gradient represents the degree of obstruction that has to be overcome to eject blood from the left ventricle.{{citation needed|date=February 2021}}

The Brockenbrough–Braunwald–Morrow sign is observed in individuals with hypertrophic cardiomyopathy with an outflow tract gradient. This sign can be used to differentiate hypertrophic cardiomyopathy from aortic stenosis. In individuals with aortic stenosis, after a [[premature ventricular contraction]] (PVC), the following ventricular contraction will be more forceful, and the pressure generated in the left ventricle will be higher. Because of the fixed obstruction that the stenotic aortic valve represents, the post-PVC ascending aortic pressure will increase as well. In individuals with hypertrophic cardiomyopathy, however, the degree of obstruction will increase more than the force of contraction will increase in the post-PVC beat. The result of this is that the left ventricular pressure increases and the ascending aortic pressure ''decreases'', with an increase in the LVOT gradient. Those with a dynamic obstruction across the aortic valve (those with HOCM) will also have a decrease in the [[pulse pressure]] in the beat after a PVC.&lt;ref name=&quot;Cui 2018&quot;&gt;{{cite journal |last1=Cui |first1=Hao |last2=Nguyen |first2=Anita |last3=Schaff |first3=Hartzell V. |title=The Brockenbrough-Braunwald-Morrow sign |journal=The Journal of Thoracic and Cardiovascular Surgery |date=October 2018 |volume=156 |issue=4 |pages=1614–1615 |doi=10.1016/j.jtcvs.2018.04.095}}&lt;/ref&gt;

== Screening ==
{{Main|Hypertrophic cardiomyopathy screening}}

Although hypertrophic cardiomyopathy may be asymptomatic, affected individuals may present with symptoms ranging from mild to critical heart failure and sudden cardiac death at any point from early childhood to seniority.&lt;ref name=Mar2002&gt;{{cite journal | vauthors = Maron BJ | title = Hypertrophic cardiomyopathy: a systematic review | journal = JAMA | volume = 287 | issue = 10 | pages = 1308–1320 | date = March 2002 | pmid = 11886323 | doi = 10.1001/jama.287.10.1308 | s2cid = 19887576 | doi-access =  }}&lt;/ref&gt;&lt;ref name=&quot;Behr &amp; McKenna&quot;&gt;{{cite journal | vauthors = Behr ER, McKenna WJ | title = Hypertrophic Cardiomyopathy | journal = Current Treatment Options in Cardiovascular Medicine | volume = 4 | issue = 6 | pages = 443–453 | date = December 2002 | pmid = 12408787 | doi = 10.1007/s11936-002-0039-8 | s2cid = 8041261 }}&lt;/ref&gt; Hypertrophic cardiomyopathy is the leading cause of sudden cardiac death in young athletes in the United States, and the most common genetic cardiovascular disorder.&lt;ref name=SCD2011/&gt; One study found that the incidence of sudden cardiac death in young competitive athletes declined in the Veneto region of Italy by 89% from an unusually high baseline rate since the 1982 introduction of routine cardiac screening for athletes.&lt;ref name =&quot;Corrado et al. 2006&quot;&gt;{{cite journal | vauthors = Corrado D, Basso C, Pavei A, Michieli P, Schiavon M, Thiene G | title = Trends in sudden cardiovascular death in young competitive athletes after implementation of a preparticipation screening program | journal = JAMA | volume = 296 | issue = 13 | pages = 1593–1601 | date = October 2006 | pmid = 17018804 | doi = 10.1001/jama.296.13.1593 | doi-access = free | hdl = 11577/2438645 | hdl-access = free }}&lt;/ref&gt; As of 2010, however, studies have shown that the incidence of sudden cardiac death, among all people with hypertrophic cardiomyopathy, has declined to one percent or less.&lt;ref name=&quot;Critoph &amp; Elliot&quot;&gt;{{cite journal | vauthors = Critoph C, Elliott P | title = Hypertrophic Cardiomyopathy | journal = Cardiac Electrophysiology Clinics | volume = 2 | issue = 4 | pages = 587–598 | date = December 2010 | pmid = 28770721 | doi = 10.1016/j.ccep.2010.09.010 }}&lt;/ref&gt; Screen-positive individuals who are diagnosed with cardiac disease are usually told to avoid competitive athletics.&lt;ref&gt;{{cite journal | vauthors = Schmehil C, Malhotra D, Patel DR | title = Cardiac screening to prevent sudden death in young athletes | journal = Translational Pediatrics | volume = 6 | issue = 3 | pages = 199–206 | date = July 2017 | pmid = 28795011 | pmc = 5532197 | doi = 10.21037/tp.2017.05.04 | doi-access = free }}&lt;/ref&gt;

Hypertrophic cardiomyopathy can be detected with an [[echocardiogram]] (ECHO) with 80%+ accuracy,&lt;ref&gt;{{cite journal | vauthors = Parato VM, Antoncecchi V, Sozzi F, Marazia S, Zito A, Maiello M, Palmiero P | title = Echocardiographic diagnosis of the different phenotypes of hypertrophic cardiomyopathy | journal = Cardiovascular Ultrasound | volume = 14 | issue = 1 | page = 30 | date = August 2016 | pmid = 27519172 | pmc = 4982201 | doi = 10.1186/s12947-016-0072-5 | doi-access = free }}&lt;/ref&gt; which can be preceded by screening with an [[electrocardiogram]] (ECG) to test for heart abnormalities. [[Cardiac magnetic resonance imaging]] (CMR), considered the gold standard for determining the physical properties of the left ventricular wall, can serve as an alternative screening tool when an echocardiogram provides inconclusive results.&lt;ref name=&quot;magnetic res. imaging&quot;&gt;{{cite journal | vauthors = Germans T, Wilde AA, Dijkmans PA, Chai W, Kamp O, Pinto YM, van Rossum AC | title = Structural abnormalities of the inferoseptal left ventricular wall detected by cardiac magnetic resonance imaging in carriers of hypertrophic cardiomyopathy mutations | journal = Journal of the American College of Cardiology | volume = 48 | issue = 12 | pages = 2518–2523 | date = December 2006 | pmid = 17174192 | doi = 10.1016/j.jacc.2006.08.036 | doi-access =  }}&lt;/ref&gt; For example, the identification of segmental lateral ventricular hypertrophy cannot be accomplished with echocardiography alone. Also, left ventricular hypertrophy may be absent in children under thirteen years of age. This reduces sensitivity of pre-adolescents' echocardiograms.&lt;ref name=Mar2002/&gt; 

=== United States ===
The [[American Academy of Pediatrics]] recommends screening questions for all children (both athletes and non-athletes) to assess the risk of congenital heart disease, inherited cardiac disorders (including hypertrophic cardiomyopathy) and sudden cardiac arrest or death. The questions assess symptoms such as syncope (passing out) or seizures in the child, exercise related chest pain or shortness of breath, having a family member with sudden cardiac death before age 50, having a family history of hypertrophic cardiomyopathy, HOCM, or a family member requiring a pacemaker or implantable cardiac defibrillator before the age of 50.&lt;ref name=&quot;Erickson 2021&quot;&gt;{{cite journal |last1=Erickson |first1=Christopher C. |last2=Salerno |first2=Jack C. |last3=Berger |first3=Stuart |last4=Campbell |first4=Robert |last5=Cannon |first5=Bryan |last6=Christiansen |first6=James |last7=Moffatt |first7=Kody |last8=Pflaumer |first8=Andreas |last9=Snyder |first9=Christopher S. |last10=Srinivasan |first10=Chandra |last11=Valdes |first11=Santiago O. |last12=Vetter |first12=Victoria L. |last13=Zimmerman |first13=Frank |title=Sudden Death in the Young: Information for the Primary Care Provider |journal=Pediatrics |date=1 July 2021 |volume=148 |issue=1 |doi=10.1542/peds.2021-052044}}&lt;/ref&gt; The role of universal EKG or non-invasive cardiac imaging in amateur or recreational athletes is not well established.&lt;ref name=&quot;Petek 2020&quot;&gt;{{cite journal |last1=Petek |first1=Bradley J. |last2=Baggish |first2=Aaron L. |title=Pre-participation Cardiovascular Screening in Young Competitive Athletes |journal=Current Emergency and Hospital Medicine Reports |date=September 2020 |volume=8 |issue=3 |pages=77–89 |doi=10.1007/s40138-020-00214-5|pmc=7863976 }}&lt;/ref&gt;

There are several potential challenges associated with routine screening for hypertrophic cardiomyopathy in the United States.&lt;ref name=&quot;Maron-2010&quot;&gt;{{cite journal | vauthors = Maron BJ | title = National electrocardiography screening for competitive athletes: Feasible in the United States? | journal = Annals of Internal Medicine | volume = 152 | issue = 5 | pages = 324–326 | date = March 2010 | pmid = 20194239 | doi = 10.7326/0003-4819-152-5-201003020-00012 | s2cid = 37588552 | citeseerx = 10.1.1.668.3787 }}&lt;/ref&gt; First, the U.S. athlete population of 15 million is large compared to other countries.&lt;ref name=&quot;Maron-2010&quot;/&gt; Second, these events are rare, with fewer than 100 deaths in the U.S. due to hypertrophic cardiomyopathy in competitive athletes per year, or about 1 death per 220,000 athletes.&lt;ref name=&quot;Maron-2009&quot;&gt;{{cite journal | vauthors = Maron BJ, Doerer JJ, Haas TS, Tierney DM, Mueller FO | title = Sudden deaths in young competitive athletes: analysis of 1866 deaths in the United States, 1980-2006 | journal = Circulation | volume = 119 | issue = 8 | pages = 1085–1092 | date = March 2009 | pmid = 19221222 | doi = 10.1161/CIRCULATIONAHA.108.804617 | doi-access = free }}&lt;/ref&gt; Lastly, genetic testing may suggest a diagnosis of hypertrophic cardiomyopathy; however, due to the numerous HCM-causing mutations, this method of screening is complex and is not cost-effective.&lt;ref name=Mar2002 /&gt;

=== Canada ===
Canadian genetic testing guidelines and recommendations for individuals diagnosed with hypertrophic cardiomyopathy are as follows:&lt;ref name=&quot;Canada Gen Test&quot;&gt;{{cite journal | vauthors = Gollob MH, Blier L, Brugada R, Champagne J, Chauhan V, Connors S, Gardner M, Green MS, Gow R, Hamilton R, Harris L, Healey JS, Hodgkinson K, Honeywell C, Kantoch M, Kirsh J, Krahn A, Mullen M, Parkash R, Redfearn D, Rutberg J, Sanatani S, Woo A | title = Recommendations for the use of genetic testing in the clinical evaluation of inherited cardiac arrhythmias associated with sudden cardiac death: Canadian Cardiovascular Society/Canadian Heart Rhythm Society joint position paper | journal = The Canadian Journal of Cardiology | volume = 27 | issue = 2 | pages = 232–245 | year = 2011 | pmid = 21459272 | doi = 10.1016/j.cjca.2010.12.078 | doi-access = free }}&lt;/ref&gt;
* The main purpose of genetic testing is to screen family members.
** According to the results, at-risk relatives may be encouraged to undergo extensive testing.
* Genetic testing is not meant to confirm a diagnosis.
* Genetic testing is not intended for risk assessment or treatment decisions.
** Evidence only supports clinical testing in predicting the progression and risk of developing complications of hypertrophic cardiomyopathy.

==Treatment==

===Asymptomatic people===
A significant number of people with hypertrophic cardiomyopathy do not have any symptoms and will have a normal life expectancy, although they should avoid particularly strenuous activities or competitive athletics. Asymptomatic people should be screened for risk factors for sudden cardiac death. In people with resting or inducible outflow obstructions, situations that will cause dehydration or vasodilation (such as the use of vasodilatory or diuretic blood pressure medications) should be avoided. Septal reduction therapy is not recommended in asymptomatic people.&lt;ref name=JACC2011/&gt;

===Medications===
The primary goal of medications in the treatment of hypertrophic cardiomyopathy is to relieve symptoms such as chest pain, shortness of breath, and palpitations. [[Beta blockers]] are considered first-line agents, as they can reduce the outflow obstruction, reduce heart strain and relieve anginal symptoms.&lt;ref name=&quot;Braunwald 2025&quot; /&gt; Beta-blockers can also slow the heart rate and decrease the likelihood of ectopic beats. For people who cannot tolerate beta-blockers, nondihydropyridine [[calcium channel blockers]] such as [[verapamil]] can be used, but are potentially harmful in people who also have low blood pressure or severe shortness of breath at rest. These medications also decrease the heart rate, though their use in people with severe outflow obstruction, elevated pulmonary artery wedge pressure, and low blood pressure should be done with caution. Dihydropyridine calcium channel blockers should be avoided in people with evidence of obstruction. For people whose symptoms are not relieved by the above treatments, [[disopyramide]] can be considered for further symptom relief. Diuretics can be considered for people with evidence of fluid overload, though cautiously used in those with evidence of obstruction.&lt;ref name=&quot;:1&quot; /&gt; Intravenous phenylephrine (or another pure vasoconstricting agent) can be used in the acute setting of low blood pressure in those with obstructive hypertrophic cardiomyopathy who do not respond to fluid administration.&lt;ref name=JACC2011/&gt;

Cardiac myosin inhibitors reduce left ventricular contractility by inhibiting cardiac [[ATPase]] to decrease the number of active actin–myosin cross-bridges within the myocyte sarcomere.&lt;ref name=&quot;Braunwald 2025&quot; /&gt;&lt;ref&gt;{{Cite journal |last1=Masri |first1=Ahmad |last2=Olivotto |first2=Iacopo |date=3 May 2022 |title=Cardiac Myosin Inhibitors as a Novel Treatment Option for Obstructive Hypertrophic Cardiomyopathy: Addressing the Core of the Matter |journal=Journal of the American Heart Association |language=en |volume=11 |issue=9 |article-number=e024656 |doi=10.1161/JAHA.121.024656 |issn=2047-9980 |pmc=9238628 |pmid=35502770}}&lt;/ref&gt; [[Mavacamten]] was shown to reduce left ventricular outflow tract gradient (a measure of obstruction) and improve symptoms in patients with obstructive hypertrophic cardiomyopathy, and was approved for medical use in the United States in April 2022.&lt;ref&gt;{{cite press release | title=U.S. Food and Drug Administration Approves Camzyos (mavacamten) for the Treatment of Adults With Symptomatic New York Heart Association Class II-III Obstructive Hypertrophic Cardiomyopathy (HCM) to Improve Functional Capacity and Symptoms | publisher=Bristol Myers Squibb | via=Business Wire | date=28 April 2022 | url=https://www.businesswire.com/news/home/20220428006368/en | access-date=29 April 2022}}&lt;/ref&gt; Mavamectin was also shown to reduce left ventricular wall thickness in those with hypertrophic cardiomyopathy and was associated with a lower need for septal reduction surgery.&lt;ref name=&quot;Braunwald 2025&quot; /&gt; [[Aficamten]], which has a shorter half life compared with mavacamten, achieves steady state within 2 weeks, and appears to have a wide therapeutic window, was shown to improve peak oxygen uptake during cardiopulmonary exercise testing in patients with New York Heart Association (NYHA) functional class II or III [[heart failure]] and decreased exercise capacity.&lt;ref&gt;{{Cite journal |last1=Maron |first1=Martin S. |last2=Masri |first2=Ahmad |last3=Nassif |first3=Michael E. |last4=Barriales-Villa |first4=Roberto |last5=Arad |first5=Michael |last6=Cardim |first6=Nuno |last7=Choudhury |first7=Lubna |last8=Claggett |first8=Brian |last9=Coats |first9=Caroline J. |last10=Düngen |first10=Hans-Dirk |last11=Garcia-Pavia |first11=Pablo |last12=Hagège |first12=Albert A. |last13=Januzzi |first13=James L. |last14=Lee |first14=Matthew M.Y. |last15=Lewis |first15=Gregory D. |date=13 May 2024 |title=Aficamten for Symptomatic Obstructive Hypertrophic Cardiomyopathy |url=http://www.nejm.org/doi/10.1056/NEJMoa2401424 |journal=New England Journal of Medicine |volume=390 |issue=20 |pages=1849–1861 |language=en |doi=10.1056/NEJMoa2401424 |pmid=38739079 |issn=0028-4793|url-access=subscription }}&lt;/ref&gt;

[[Aficamten]] (Myqorzo) was approved for medical use in the United States in December 2025, for the treatment of symptomatic obstructive hypertrophic cardiomyopathy.&lt;ref name=&quot;FDA PR 20251222&quot;&gt;{{cite press release | title=FDA approves drug to improve functional capacity and symptoms in adults with rare inherited heart condition | website=U.S. [[Food and Drug Administration]] (FDA) | date=22 December 2025 | url=https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-drug-improve-functional-capacity-and-symptoms-adults-rare-inherited-heart-condition | access-date=22 December 2025}}&lt;/ref&gt;&lt;ref&gt;{{cite press release | title=Cytokinetics Announces FDA Approval of Myqorzo (aficamten) for the Treatment of Adults with Symptomatic Obstructive Hypertrophic Cardiomyopathy to Improve Functional Capacity and Symptoms | publisher=Cytokinetics | via=GlobeNewswire News Room | date=19 December 2025 | url=https://www.globenewswire.com/news-release/2025/12/19/3208724/35409/en/Cytokinetics-Announces-FDA-Approval-of-MYQORZO-aficamten-for-the-Treatment-of-Adults-with-Symptomatic-Obstructive-Hypertrophic-Cardiomyopathy-to-Improve-Functional-Capacity-and-Sym.html | access-date=22 December 2025}}&lt;/ref&gt;

===Surgical septal myectomy===
{{Main|Septal myectomy}}
Surgical [[septal myectomy]] is an [[Open heart surgery|open-heart operation]] done to relieve symptoms in people who remain severely symptomatic despite medical therapy. It has been performed successfully since the early 1960s.&lt;ref name=&quot;Maron, McKenna et al. 2003&quot;/&gt; Surgical septal myectomy uniformly decreases left ventricular outflow tract obstruction and improves symptoms, and in experienced centers has a surgical mortality of less than 1%, as well as 85% success rate.&lt;ref name=&quot;Behr &amp; McKenna&quot; /&gt; It involves a median sternotomy (opening the chest) and removing a portion of the interventricular septum.&lt;ref name=Mar2002/&gt; Surgical myectomy resection that focuses just on the subaortic septum, to increase the size of the outflow tract to reduce Venturi forces, may be inadequate to abolish systolic anterior motion (SAM) of the anterior leaflet of the mitral valve. With this limited resection, the residual mid-septal bulge still redirects flow posteriorly; SAM persists because flow still gets behind the mitral valve. It is only when the deeper portion of the septal bulge is resected that flow is redirected anteriorly away from the mitral valve, abolishing SAM. With this in mind, a modification of the Morrow myectomy termed extended myectomy, mobilization and partial excision of the papillary muscles has become the excision of choice.&lt;ref name=&quot;Sherrid Chaudhry et al. 2003&quot;&gt;{{cite journal | vauthors = Sherrid MV, Chaudhry FA, Swistel DG | title = Obstructive hypertrophic cardiomyopathy: echocardiography, pathophysiology, and the continuing evolution of surgery for obstruction | journal = The Annals of Thoracic Surgery | volume = 75 | issue = 2 | pages = 620–632 | date = February 2003 | pmid = 12607696 | doi = 10.1016/S0003-4975(02)04546-0 | doi-access = free }}&lt;/ref&gt;&lt;ref name=&quot;Messmer 1994&quot;&gt;{{cite journal | vauthors = Messmer BJ | title = Extended myectomy for hypertrophic obstructive cardiomyopathy | journal = The Annals of Thoracic Surgery | volume = 58 | issue = 2 | pages = 575–577 | date = August 1994 | pmid = 8067875 | doi = 10.1016/0003-4975(94)92268-3 }}&lt;/ref&gt;&lt;ref name=&quot;Schoendube, Klues et al. 1995&quot;&gt;{{cite journal | vauthors = Schoendube FA, Klues HG, Reith S, Flachskampf FA, Hanrath P, Messmer BJ | title = Long-term clinical and echocardiographic follow-up after surgical correction of hypertrophic obstructive cardiomyopathy with extended myectomy and reconstruction of the subvalvular mitral apparatus | journal = Circulation | volume = 92 | issue = 9 Suppl | pages = II122–II127 | date = November 1995 | pmid = 7586394 | doi = 10.1161/01.CIR.92.9.122 }}&lt;/ref&gt;&lt;ref name=&quot;Balaram, Sherrid et al. 2005&quot;&gt;{{cite journal | vauthors = Balaram SK, Sherrid MV, Derose JJ, Hillel Z, Winson G, Swistel DG | title = Beyond extended myectomy for hypertrophic cardiomyopathy: the resection-plication-release (RPR) repair | journal = The Annals of Thoracic Surgery | volume = 80 | issue = 1 | pages = 217–223 | date = July 2005 | pmid = 15975370 | doi = 10.1016/j.athoracsur.2005.01.064 | doi-access = free }}&lt;/ref&gt; In people with particularly large redundant mitral valves, anterior leaflet plication may be added to complete separation of the mitral valve and outflow.&lt;ref name=&quot;Balaram, Sherrid et al. 2005&quot;/&gt; Complications of septal myectomy surgery include possible death, arrhythmias, infection, bleeding, septal perforation/defect, and stroke.&lt;ref name=&quot;Behr &amp; McKenna&quot; /&gt;

===Alcohol septal ablation===
{{Main|Alcohol septal ablation}}
[[Alcohol septal ablation]], introduced by [[Ulrich Sigwart]] in 1994, is a [[percutaneous]] technique that involves an injection of alcohol into one or more septal branches of the [[coronary circulation|left anterior descending artery]]. This is a [[catheter]] technique with results similar to the surgical septal myectomy procedure but is less invasive since it does not involve general anesthesia and opening of the chest wall and pericardium (which are done in a septal myectomy). In a select population with symptoms secondary to a high outflow tract gradient, alcohol septal ablation can reduce the symptoms of hypertrophic cardiomyopathy. In addition, older individuals and those with other medical problems, for whom surgical myectomy would pose an increased procedural risk, would likely benefit from the less-invasive septal ablation procedure.&lt;ref name=Mar2002/&gt;&lt;ref&gt;{{cite journal | vauthors = Sigwart U | title = Non-surgical myocardial reduction for hypertrophic obstructive cardiomyopathy | journal = Lancet | volume = 346 | issue = 8969 | pages = 211–214 | date = July 1995 | pmid = 7616800 | doi = 10.1016/S0140-6736(95)91267-3 | s2cid = 32959772 }}&lt;/ref&gt;

When performed properly, an alcohol septal ablation induces a controlled [[myocardial infarction|heart attack]], in which the portion of the interventricular septum that involves the left ventricular outflow tract is infarcted and will contract into a scar.

Alcohol septal ablation has a risk of secondary [[complete heart block]] as well as a greater need for repeated procedures due to persistent outflow tract obstruction.&lt;ref name=&quot;Braunwald 2025&quot; /&gt; Septal reduction surgery and alcohol septal ablation have a similar risk of death related to procedural complications.&lt;ref name=&quot;Braunwald 2025&quot; /&gt;

===Mitral clip===
{{Main|MitraClip}}
Since 2013, [[mitral clip]]s have been implanted via a catheter as a new strategy to correct the motion of the mitral valve in people with severe obstructive hypertrophic cardiomyopathy (= oHCM). The device fastens together the mitral valve leaflets to improve the heart's blood outflow. The mitral clip has not yet established the same long-term reliability as septal myectomy or alcohol septal ablation, but hypertrophic cardiomyopathy specialists are increasingly offering the clip as a less-invasive treatment option.&lt;ref&gt;{{cite journal | vauthors = Dimitrow PP, Rajtar-Salwa R | title = Obstructive Form of Hypertrophic Cardiomyopathy-Left Ventricular Outflow Tract Gradient: Novel Methods of Provocation, Monitoring of Biomarkers, and Recent Advances in the Treatment | journal = BioMed Research International | volume = 2016 | article-number = 1575130 | date = May 2016 | pmid = 27247935 | pmc = 4877458 | doi = 10.1155/2016/1575130 | doi-access = free }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Sorajja P, Pedersen WA, Bae R, Lesser JR, Jay D, Lin D, Harris K, Maron BJ | title = First Experience With Percutaneous Mitral Valve Plication as Primary Therapy for Symptomatic Obstructive Hypertrophic Cardiomyopathy | journal = Journal of the American College of Cardiology | volume = 67 | issue = 24 | pages = 2811–2818 | date = June 2016 | pmid = 27311518 | doi = 10.1016/j.jacc.2016.03.587 | doi-access = free }}&lt;/ref&gt;

===Implantable pacemaker or defibrillator===
{{Further|Pacemaker|ICD device}}
The use of a [[artificial pacemaker|pacemaker]] has been advocated in a subset of individuals, to cause asynchronous contraction of the left ventricle. Since the pacemaker activates the interventricular septum before the left ventricular free wall, the gradient across the left ventricular outflow tract may decrease. This form of treatment has been shown to provide less relief of symptoms and less of a reduction in the left ventricular outflow tract gradient when compared to surgical myectomy.&lt;ref name=&quot;Ommen, Nishimura et al. 1999&quot;&gt;{{cite journal | vauthors = Ommen SR, Nishimura RA, Squires RW, Schaff HV, Danielson GK, Tajik AJ | title = Comparison of dual-chamber pacing versus septal myectomy for the treatment of patients with hypertrophic obstructive cardiomyopathy: a comparison of objective hemodynamic and exercise end points | journal = Journal of the American College of Cardiology | volume = 34 | issue = 1 | pages = 191–196 | date = July 1999 | pmid = 10400010 | doi = 10.1016/S0735-1097(99)00173-4 | doi-access =  }}&lt;/ref&gt; Technological advancements have also led to the development of a dual-chamber pacemaker, which is only turned on when needed (in contrast to a regular pacemaker which provides a constant stimulus). Although the dual-chamber pacemaker has been shown to decrease ventricular outflow tract obstruction, experimental trials have found only a few individuals with improved symptoms.&lt;ref name=&quot;Coats &amp; Elliot&quot;&gt;{{cite journal | vauthors = Coats CJ, Elliott PM | title = Current management of hypertrophic cardiomyopathy | journal = Current Treatment Options in Cardiovascular Medicine | volume = 10 | issue = 6 | pages = 496–504 | date = December 2008 | pmid = 19026180 | doi = 10.1007/s11936-008-0042-9 | s2cid = 318803 }}&lt;/ref&gt; Researchers suspect that these reports of improved symptoms are due to a [[placebo]] effect.&lt;ref name=&quot;Behr &amp; McKenna&quot; /&gt;

The procedure includes an incision on the anterolateral area below the clavicle. Two leads are then inserted; one into the right atrium and the other into the right ventricular apex via the subclavian veins. Once in place, they are secured and attached to the generator which will remain inside the fascia, anterior to the pectoral muscle.&lt;ref name=&quot;Behr &amp; McKenna&quot; /&gt; Complications of this procedure include infection, electrical lead, and generator malfunction which will require replacement.&lt;ref name=&quot;Behr &amp; McKenna&quot; /&gt;

For people with hypertrophic cardiomyopathy who exhibit one or more of the major risk factors for sudden cardiac death, an [[implantable cardioverter-defibrillator]] (ICD) or a combination pacemaker/ICD all-in-one unit may be recommended as an appropriate precaution.&lt;ref name=JACC2011 /&gt;&lt;ref name=&quot;Maron, McKenna et al. 2003&quot; /&gt;&lt;ref&gt;{{cite journal | vauthors = Maron BJ, Spirito P, Shen WK, Haas TS, Formisano F, Link MS, Epstein AE, Almquist AK, Daubert JP, Lawrenz T, Boriani G, Estes NA, Favale S, Piccininno M, Winters SL, Santini M, Betocchi S, Arribas F, Sherrid MV, Buja G, Semsarian C, Bruzzi P | title = Implantable cardioverter-defibrillators and prevention of sudden cardiac death in hypertrophic cardiomyopathy | journal = JAMA | volume = 298 | issue = 4 | pages = 405–412 | date = July 2007 | pmid = 17652294 | doi = 10.1001/jama.298.4.405 | doi-access =  | hdl = 11380/1080474 | hdl-access = free }}&lt;/ref&gt;&lt;ref&gt;{{cite web |url=http://www.4hcm.org/content.asp?contentid=167 |title=ICDs and Pacemakers |publisher=Hypertrophic Cardiomyopathy Association |access-date=14 November 2016 |archive-url=https://web.archive.org/web/20161115132702/http://www.4hcm.org/content.asp?contentid=167 |archive-date=15 November 2016 |url-status=live }}&lt;/ref&gt; In 2014, [[European Society of Cardiology]] suggested a practical risk score to calculate that risk.&lt;ref&gt;{{cite web |url=https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Hypertrophic-Cardiomyopathy |title=2014 ESC Guidelines on diagnosis and management of hypertrophic cardiomyopathy |access-date=22 November 2020 |archive-date=5 December 2020 |archive-url=https://web.archive.org/web/20201205131051/https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Hypertrophic-Cardiomyopathy |url-status=live }}&lt;/ref&gt;

===Cardiac transplantation===
{{Further|Cardiac transplantation}}
In cases that are unresponsive to all other forms of treatment, [[heart transplant|cardiac transplantation]] is one option. It is also the only treatment available for end-stage heart failure.&lt;ref name=&quot;Coats &amp; Elliot&quot; /&gt; Studies have indicated a seven-year survival rate of 94% in people with hypertrophic cardiomyopathy after transplantation.&lt;ref name=&quot;Coats &amp; Elliot&quot; /&gt;

==Prognosis==
The annual mortality rate in those with hypertrophic cardiomyopathy is 1%.&lt;ref name=Mar2002/&gt; 70% of those with hypertrophic cardiomyopathy have a left ventricular outflow tract obstruction (HOCM).&lt;ref name=&quot;Braunwald 2025&quot; /&gt;

A family history of sudden cardiac death, left ventricular wall thickness greater than 30 milimeters, an aneurysm at the left ventricular apex, unexplained syncope (passing out) multiple episodes of sustained ventricular tachycardia, late gadolinium enhancement on cardiac MRI (a marker of heart muscle fibrosis or scar formation) and a left ventricular ejection fraction of less than 50% are all risk factors for sudden cardiac death in hypertrophic cardiomyopathy. The incidence of sudden cardiac in those older than 60 with hypertrophic cardiomyopathy is rare.&lt;ref name=&quot;Braunwald 2025&quot;&gt;{{cite journal |last1=Braunwald |first1=Eugene |title=Hypertrophic Cardiomyopathy |journal=New England Journal of Medicine |date=30 August 2025 |doi=10.1056/NEJMra2413445}}&lt;/ref&gt;

About 25% of those with symptomatic hypertrophic cardiomyopathy have [[atrial fibrillation]] (in which the atrial chambers of the heart beat irregularly, and sometimes rapidly). Those with hypertrophic cardiomyopathy and atrial fibrillation have a worse prognosis, partly due to the loss of the contribution of atrial contractility to heart function and the fast heart rate impairing ventricular filling.&lt;ref name=&quot;Braunwald 2025&quot;/&gt;

==Children==
Even though hypertrophic cardiomyopathy may be present early in life and is most likely congenital, it is not commonly seen in pediatric cardiology, largely because the presentation of symptoms is usually absent, incomplete, or delayed into adulthood. Most of the information pertaining to hypertrophic cardiomyopathy arises from studies in adult populations, and the implication of these observations for the pediatric population is uncertain.&lt;ref name=&quot;Colan 2010 433–444&quot;&gt;{{cite journal | vauthors = Colan SD | title = Hypertrophic cardiomyopathy in childhood | journal = Heart Failure Clinics | volume = 6 | issue = 4 | pages = 433–44, vii-iii | date = October 2010 | pmid = 20869644 | pmc = 2946944 | doi = 10.1016/j.hfc.2010.05.004 }}&lt;/ref&gt; Nonetheless, studies in pediatric cardiology have revealed that hypertrophic cardiomyopathy accounts for 42% of childhood cardiomyopathies, with an annual incidence rate of 0.47/100,000 in children.&lt;ref&gt;{{cite journal | vauthors = Lipshultz SE, Sleeper LA, Towbin JA, Lowe AM, Orav EJ, Cox GF, Lurie PR, McCoy KL, McDonald MA, Messere JE, Colan SD | title = The incidence of pediatric cardiomyopathy in two regions of the United States | journal = The New England Journal of Medicine | volume = 348 | issue = 17 | pages = 1647–1655 | date = April 2003 | pmid = 12711739 | doi = 10.1056/NEJMoa021715 | doi-access = free }}&lt;/ref&gt; In asymptomatic cases, sudden death is considered one of the most-feared complications associated with the disease. Consequently, the recommended practice is to screen children of affected individuals throughout childhood to detect cardiac abnormalities at an early stage, in the hope of preventing further complications of the disease.&lt;ref name=&quot;Colan 2010 433–444&quot;/&gt;

Generally, the diagnosis of hypertrophic cardiomyopathy in a pediatric population is made during assessment for murmur, congestive heart failure, physical exhaustion, and genetic testing of children of affected individuals.&lt;ref name=&quot;Colan 2010 433–444&quot;/&gt; Echocardiography is used to assess left ventricular wall thickness, ventricular size, systolic and diastolic heart function, and outflow tract obstruction to diagnose hypertrophic cardiomyopathy in children.&lt;ref name=&quot;Colan 2010 433–444&quot;/&gt;

For children with hypertrophic cardiomyopathy, treatment strategies aim to reduce disease symptoms and lower the risk of sudden death.&lt;ref name=&quot;Maskatia 2012 84–92&quot;&gt;{{cite journal | vauthors = Maskatia SA | title = Hypertrophic cardiomyopathy: infants, children, and adolescents | journal = Congenital Heart Disease | volume = 7 | issue = 1 | pages = 84–92 | year = 2012 | pmid = 22222117 | doi = 10.1111/j.1747-0803.2011.00613.x | doi-access = free }}&lt;/ref&gt; Due to the heterogeneity of the disease, treatment is usually modified according to individual's needs.&lt;ref name=&quot;Maskatia 2012 84–92&quot;/&gt; β-blockers improve left ventricular filling and relaxation and thereby lessen symptoms. In some children, β–blockers were shown effective in reducing the risk of sudden death.&lt;ref name=&quot;Maskatia 2012 84–92&quot;/&gt; Calcium channel blockers (verapamil) and antiarrhythmic drugs may be used as an adjunct therapy to β-blockers in symptomatic children.&lt;ref name=&quot;Maskatia 2012 84–92&quot;/&gt; Septal myectomy, if required for treatment, is considered safe in children.&lt;ref name=&quot;Braunwald 2025&quot; /&gt;

== Epidemiology ==
The prevalence of hypertrophic cardiomyopathy in the general population globally is 0.2% (1 in 500 adults), as determined by echocardiographic studies.&lt;ref name=&quot;:1&quot; /&gt; Hypertrophic cardiomyopathy is more common in males than females.&lt;ref name=&quot;:1&quot; /&gt; The most common presentation of hypertrophic cardiomyopathy is in the third decade of life, though it can present at any age, from newborns to the elderly.&lt;ref name=&quot;:1&quot; /&gt;

==Other animals==
[[File:Echocardiography of hypertrophic-obstructive cardiomyopathy in a domestic cat.gif|thumb|Echocardiography of hypertrophic-obstructive cardiomyopathy (HOCM) in a cat.]] [[File:Reitender-Thrombus-numbered.jpg|thumb|Saddle thrombus in the feline aorta. 1 opened Aorta with thrombus, 2 A. iliaca externa, 3 common trunk for both Aa. iliacae internae, 4 A. circumflexa ilium profunda, 5 A. mesenterica caudalis, 6 Colon descendens.]]

=== Cats ===
Feline hypertrophic cardiomyopathy (HCM) is the most common [[heart disease]] in domestic [[cat]]s;&lt;ref&gt;{{cite journal | vauthors = Payne JR, Brodbelt DC, Luis Fuentes V | title = Cardiomyopathy prevalence in 780 apparently healthy cats in rehoming centres (the CatScan study) | journal = Journal of Veterinary Cardiology | volume = 17 | issue = Suppl 1 | pages = S244–S257 | date = December 2015 | pmid = 26776583 | doi = 10.1016/j.jvc.2015.03.008 | url = https://researchonline.rvc.ac.uk/id/eprint/9635/1/9635.pdf | access-date = 28 September 2020 | url-status = live | archive-url = https://web.archive.org/web/20220124001035/https://researchonline.rvc.ac.uk/id/eprint/9635/1/9635.pdf | archive-date = 24 January 2022 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Paige CF, Abbott JA, Elvinger F, Pyle RL | title = Prevalence of cardiomyopathy in apparently healthy cats | journal = Journal of the American Veterinary Medical Association | volume = 234 | issue = 11 | pages = 1398–1403 | date = June 2009 | pmid = 19480619 | doi = 10.2460/javma.234.11.1398 | url = http://hdl.handle.net/10919/43704 | access-date = 14 September 2020 | url-status = live | hdl-access = free | archive-date = 9 August 2023 | archive-url = https://web.archive.org/web/20230809062454/https://vtechworks.lib.vt.edu/handle/10919/43704 | hdl = 10919/43704 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Wagner T, Fuentes VL, Payne JR, McDermott N, Brodbelt D | title = Comparison of auscultatory and echocardiographic findings in healthy adult cats | journal = Journal of Veterinary Cardiology | volume = 12 | issue = 3 | pages = 171–182 | date = December 2010 | pmid = 21075067 | doi = 10.1016/j.jvc.2010.05.003 | url = https://researchonline.rvc.ac.uk/id/eprint/5184/1/5184.pdf | access-date = 24 January 2023 | url-status = live | archive-url = https://web.archive.org/web/20230809062451/https://rvc-repository.worktribe.com | archive-date = 9 August 2023 }}&lt;/ref&gt; the disease process and genetics are believed to be similar to the disease in humans.&lt;ref name=&quot;Cornell&quot;&gt;{{cite web|title=Hypertrophic Cardiomyopathy (HCM) in Cats|url=https://www.vet.cornell.edu/hospital/Services/Companion/Cardiology/conditions/HCM.cfm|website=Cornell University Hospital for Animals|access-date=24 February 2017|archive-url=https://web.archive.org/web/20180122164528/http://www.vet.cornell.edu/hospital/Services/Companion/Cardiology/conditions/HCM.cfm|archive-date=22 January 2018|url-status=live}}&lt;/ref&gt; In [[Maine Coon]] cats, HCM has been confirmed as an autosomal dominant inherited trait.&lt;ref name=&quot;Kittleson, Meurs et al. 1999&quot;&gt;{{cite journal | vauthors = Kittleson MD, Meurs KM, Munro MJ, Kittleson JA, Liu SK, Pion PD, Towbin JA | title = Familial hypertrophic cardiomyopathy in maine coon cats: an animal model of human disease | journal = Circulation | volume = 99 | issue = 24 | pages = 3172–3180 | date = June 1999 | pmid = 10377082 | doi = 10.1161/01.CIR.99.24.3172 | doi-access = free }}&lt;/ref&gt; Numerous cat breeds have HCM as a problem in the breed.&lt;ref&gt;{{cite web|publisher=Cat Fancier's Association |url=http://www.cfa.org/articles/health/hypertrophic-cardiomyopathy.html |title=Feline Hypertrophic Cardiomyopathy: Advice for Breeders | vauthors = Kittleson M, Gompf R, Little S |archive-url=https://web.archive.org/web/20080513083815/http://www.cfa.org/articles/health/hypertrophic-cardiomyopathy.html |archive-date=13 May 2008 }}&lt;/ref&gt; The first genetic mutation (in cardiac myosin binding protein C) responsible for feline HCM was discovered in 2005 in Maine Coon cats.&lt;ref name=&quot;Meurs, Sanchez et al. 2005&quot;&gt;{{cite journal | vauthors = Meurs KM, Sanchez X, David RM, Bowles NE, Towbin JA, Reiser PJ, Kittleson JA, Munro MJ, Dryburgh K, Macdonald KA, Kittleson MD | title = A cardiac myosin binding protein C mutation in the Maine Coon cat with familial hypertrophic cardiomyopathy | journal = Human Molecular Genetics | volume = 14 | issue = 23 | pages = 3587–3593 | date = December 2005 | pmid = 16236761 | doi = 10.1093/hmg/ddi386 | doi-access = free }}&lt;/ref&gt; A test for this mutation (A31P) is available.&lt;ref&gt;{{cite web |url=https://cvm.ncsu.edu/genetics/maine-coon-cat-hypertrophic-cardiomyopathy-hcm/ |title=Genetics: Maine Coon Cat Hypertrophic Cardiomyopathy |publisher=North Carolina State University, College of Veterinary Medicine |access-date=29 December 2016 |archive-url=https://web.archive.org/web/20190903231222/https://cvm.ncsu.edu/genetics/maine-coon-cat-hypertrophic-cardiomyopathy-hcm/ |archive-date=3 September 2019 |url-status=live }}&lt;/ref&gt; About one-third of Maine Coon cats tested for the mutation are either heterozygous or homozygous for the mutation, although many of the cats that are heterozygous have no overt evidence of the disease on an echocardiogram (low penetrance). 

Some Maine Coon cats with clinical evidence of hypertrophic cardiomyopathy test negative for this mutation, strongly suggesting that another cause exists in the breed. The cardiac myosin binding protein C mutation identified in Maine Coon cats has not been found in any other breed of cat with HCM, but more recently another myosin binding protein C mutation has been identified in Ragdoll cats with HCM.&lt;ref name=&quot;Meurs, Kittleson et al. 2007&quot;&gt;{{cite journal | vauthors = Meurs KM, Norgard MM, Ederer MM, Hendrix KP, Kittleson MD | title = A substitution mutation in the myosin binding protein C gene in ragdoll hypertrophic cardiomyopathy | journal = Genomics | volume = 90 | issue = 2 | pages = 261–264 | date = August 2007 | pmid = 17521870 | doi = 10.1016/j.ygeno.2007.04.007 | doi-access =  }}&lt;/ref&gt;&lt;ref&gt;{{cite web |url=https://cvm.ncsu.edu/genetics/ragdoll-cat-hypertrophic-cardiomyopathy-hcm/ |title=Genetics: Ragdoll Cat Hypertrophic Cardiomyopathy |publisher=North Carolina State University, College of Veterinary Medicine |access-date=29 December 2016 |archive-url=https://web.archive.org/web/20161214054308/https://cvm.ncsu.edu/genetics/ragdoll-cat-hypertrophic-cardiomyopathy-hcm/ |archive-date=14 December 2016 |url-status=live }}&lt;/ref&gt; As in humans, feline HCM is not present at birth but develops over time. It has been identified for the first time in cats as young as 6 months of age and at least as old as 7 years of age.{{citation needed|date=February 2021}}

Clinically, cats with hypertrophic cardiomyopathy commonly have a systolic anterior motion (SAM) of the mitral valve (see graphic).&lt;ref&gt;{{cite journal | vauthors = Schober K, Todd A | title = Echocardiographic assessment of left ventricular geometry and the mitral valve apparatus in cats with hypertrophic cardiomyopathy | journal = Journal of Veterinary Cardiology | volume = 12 | issue = 1 | pages = 1–16 | date = April 2010 | pmid = 20185379 | doi = 10.1016/j.jvc.2009.09.004 }}&lt;/ref&gt; Cats with severe HCM often develop left heart failure (pulmonary edema; pleural effusion) because of severe diastolic dysfunction of the left ventricle. They may also develop a left atrial thrombus that embolizes, most commonly, to the terminal aorta creating acute pain and rear limb paralysis (see below). Sudden death can also occur but appears to be uncommon.&lt;ref&gt;{{cite journal | vauthors = Fox PR, Keene BW, Lamb K, Schober KA, Chetboul V, Luis Fuentes V, Wess G, Payne JR, Hogan DF, Motsinger-Reif A, Häggström J, Trehiou-Sechi E, Fine-Ferreira DM, Nakamura RK, Lee PM, Singh MK, Ware WA, Abbott JA, Culshaw G, Riesen S, Borgarelli M, Lesser MB, Van Israël N, Côté E, Rush JE, Bulmer B, Santilli RA, Vollmar AC, Bossbaly MJ, Quick N, Bussadori C, Bright JM, Estrada AH, Ohad DG, Fernández-Del Palacio MJ, Lunney Brayley J, Schwartz DS, Bové CM, Gordon SG, Jung SW, Brambilla P, Moïse NS, Stauthammer CD, Stepien RL, Quintavalla C, Amberger C, Manczur F, Hung YW, Lobetti R, De Swarte M, Tamborini A, Mooney CT, Oyama MA, Komolov A, Fujii Y, Pariaut R, Uechi M, Tachika Ohara VY | title = International collaborative study to assess cardiovascular risk and evaluate long-term health in cats with preclinical hypertrophic cardiomyopathy and apparently healthy cats: The REVEAL Study | journal = Journal of Veterinary Internal Medicine | volume = 32 | issue = 3 | pages = 930–943 | date = May 2018 | pmid = 29660848 | pmc = 5980443 | doi = 10.1111/jvim.15122 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Fox PR, Keene BW, Lamb K, Schober KE, Chetboul V, Luis Fuentes V, Payne JR, Wess G, Hogan DF, Abbott JA, Häggström J, Culshaw G, Fine-Ferreira D, Cote E, Trehiou-Sechi E, Motsinger-Reif AA, Nakamura RK, Singh M, Ware WA, Riesen SC, Borgarelli M, Rush JE, Vollmar A, Lesser MB, Van Israel N, Lee PM, Bulmer B, Santilli R, Bossbaly MJ, Quick N, Bussadori C, Bright J, Estrada AH, Ohad DG, Del Palacio MJ, Brayley JL, Schwartz DS, Gordon SG, Jung S, Bove CM, Brambilla PG, Moïse NS, Stauthammer C, Quintavalla C, Manczur F, Stepien RL, Mooney C, Hung YW, Lobetti R, Tamborini A, Oyama MA, Komolov A, Fujii Y, Pariaut R, Uechi M, Yukie Tachika Ohara V | title = Long-term incidence and risk of noncardiovascular and all-cause mortality in apparently healthy cats and cats with preclinical hypertrophic cardiomyopathy | journal = Journal of Veterinary Internal Medicine | volume = 33 | issue = 6 | pages = 2572–2586 | date = November 2019 | pmid = 31605422 | pmc = 6872868 | doi = 10.1111/jvim.15609 }}&lt;/ref&gt;

Ultrasound of the heart ([[echocardiography]]) is necessary to diagnose HCM in cats.&lt;ref&gt;{{cite journal | vauthors = Luis Fuentes V, Wilkie LJ | title = Asymptomatic Hypertrophic Cardiomyopathy: Diagnosis and Therapy | journal = The Veterinary Clinics of North America. Small Animal Practice | volume = 47 | issue = 5 | pages = 1041–1054 | date = September 2017 | pmid = 28662873 | doi = 10.1016/j.cvsm.2017.05.002 | url = https://researchonline.rvc.ac.uk/id/eprint/10891/1/10891.pdf | access-date = 28 September 2020 | url-status = live | archive-url = https://web.archive.org/web/20210122230137/https://researchonline.rvc.ac.uk/id/eprint/10891/1/10891.pdf | archive-date = 22 January 2021 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Häggström J, Luis Fuentes V, Wess G | title = Screening for hypertrophic cardiomyopathy in cats | journal = Journal of Veterinary Cardiology | volume = 17 | issue = Suppl 1 | pages = S134–S149 | date = December 2015 | pmid = 26776573 | doi = 10.1016/j.jvc.2015.07.003 | url = http://researchonline.rvc.ac.uk/id/eprint/9946/ | url-access = subscription }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Luis Fuentes V, Abbott J, Chetboul V, Côté E, Fox PR, Häggström J, Kittleson MD, Schober K, Stern JA | title = ACVIM consensus statement guidelines for the classification, diagnosis, and management of cardiomyopathies in cats | journal = Journal of Veterinary Internal Medicine | volume = 34 | issue = 3 | pages = 1062–1077 | date = May 2020 | pmid = 32243654 | pmc = 7255676 | doi = 10.1111/jvim.15745 }}&lt;/ref&gt; Measurement of circulating cardiac [[Biomarker (medicine)|biomarkers]], like N‐terminal‐proBNP ([[N-terminal prohormone of brain natriuretic peptide|NT‐proBNP]])&lt;ref&gt;{{cite journal | vauthors = Fox PR, Rush JE, Reynolds CA, Defrancesco TC, Keene BW, Atkins CE, Gordon SG, Schober KE, Bonagura JD, Stepien RL, Kellihan HB, Macdonald KA, Lehmkuhl LB, Nguyenba TP, Sydney Moise N, Lefbom BK, Hogan DF, Oyama MA | title = Multicenter evaluation of plasma N-terminal probrain natriuretic peptide (NT-pro BNP) as a biochemical screening test for asymptomatic (occult) cardiomyopathy in cats | journal = Journal of Veterinary Internal Medicine | volume = 25 | issue = 5 | pages = 1010–1016 | date = September 2011 | pmid = 21985136 | doi = 10.1111/j.1939-1676.2011.00776.x | doi-access = free }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Wess G, Daisenberger P, Mahling M, Hirschberger J, Hartmann K | title = Utility of measuring plasma N-terminal pro-brain natriuretic peptide in detecting hypertrophic cardiomyopathy and differentiating grades of severity in cats | journal = Veterinary Clinical Pathology | volume = 40 | issue = 2 | pages = 237–244 | date = June 2011 | pmid = 21434959 | doi = 10.1111/j.1939-165X.2011.00305.x }}&lt;/ref&gt; and [[troponin I]] (TnI) may be used in cats to strengthen the suspicion of cardiac disease.&lt;ref&gt;{{cite journal | vauthors = Borgeat K, Connolly DJ, Luis Fuentes V | title = Cardiac biomarkers in cats | journal = Journal of Veterinary Cardiology | volume = 17 | issue = Suppl 1 | pages = S74–S86 | date = December 2015 | pmid = 26776596 | doi = 10.1016/j.jvc.2015.08.001 | url = https://researchonline.rvc.ac.uk/id/eprint/9976/1/9976.pdf | access-date = 28 September 2020 | url-status = live | archive-url = https://web.archive.org/web/20200307033643/https://researchonline.rvc.ac.uk/id/eprint/9976/1/9976.pdf | archive-date = 7 March 2020 }}&lt;/ref&gt; There is a [[Point-of-care testing|Point-of-care]] test for feline NT-proBNP available which can be used at the veterinary clinic when echocardiography is not possible to perform.&lt;ref&gt;{{cite journal | vauthors = Hanås S, Holst BS, Höglund K, Häggström J, Tidholm A, Ljungvall I | title = Effect of feline characteristics on plasma N-terminal-prohormone B-type natriuretic peptide concentration and comparison of a point-of-care test and an ELISA test | journal = Journal of Veterinary Internal Medicine | volume = 34 | issue = 3 | pages = 1187–1197 | date = May 2020 | pmid = 32200578 | pmc = 7255655 | doi = 10.1111/jvim.15754 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Machen MC, Oyama MA, Gordon SG, Rush JE, Achen SE, Stepien RL, Fox PR, Saunders AB, Cunningham SM, Lee PM, Kellihan HB | title = Multi-centered investigation of a point-of-care NT-proBNP ELISA assay to detect moderate to severe occult (pre-clinical) feline heart disease in cats referred for cardiac evaluation | journal = Journal of Veterinary Cardiology | volume = 16 | issue = 4 | pages = 245–255 | date = December 2014 | pmid = 25456274 | doi = 10.1016/j.jvc.2014.09.002 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Harris AN, Beatty SS, Estrada AH, Winter B, Bohannon M, Sosa I, Hanscom J, Mainville CA, Gallagher AE | title = Investigation of an N-Terminal Prohormone of Brain Natriuretic Peptide Point-of-Care ELISA in Clinically Normal Cats and Cats With Cardiac Disease | journal = Journal of Veterinary Internal Medicine | volume = 31 | issue = 4 | pages = 994–999 | date = July 2017 | pmid = 28617995 | pmc = 5508306 | doi = 10.1111/jvim.14776 }}&lt;/ref&gt;

Cats that are tachycardic (&gt;220) and/or have outflow obstruction (SAM) on echo should probably be treated but there is no cure for feline HCM. Many but not all cats have a heart murmur. Many cats that have a heart murmur do not have HCM. Frequently the first signs that a cat has HCM are tachypnea/dyspnea due to heart failure or acute pain and paralysis due to systemic thromboembolism. While medication is commonly given to cats with HCM that have no clinical signs, no medication is helpful at this stage and it has been shown that an ACE inhibitor is not beneficial until heart failure is present&lt;ref name=&quot;MacDonald, Kittleson et al.&quot;&gt;{{cite journal | vauthors = MacDonald KA, Kittleson MD, Larson RF, Kass P, Klose T, Wisner ER | title = The effect of ramipril on left ventricular mass, myocardial fibrosis, diastolic function, and plasma neurohormones in Maine Coon cats with familial hypertrophic cardiomyopathy without heart failure | journal = Journal of Veterinary Internal Medicine | volume = 20 | issue = 5 | pages = 1093–1105 | year = 2006 | pmid = 17063701 | doi = 10.1111/j.1939-1676.2006.tb00707.x | doi-access = free }}&lt;/ref&gt; (at which time a diuretic is most beneficial). Diltiazem generally produces no demonstrable benefit. [[Atenolol]] is commonly administered when a severe systolic anterior motion of the mitral valve is present.{{citation needed|date=February 2021}}

Feline arterial thromboembolism (FATE) is a relatively common and devastating complication of feline hypertrophic cardiomyopathy and other feline cardiomyopathies. The thrombus generally forms in the left atrium, most commonly the left auricle. The formation is thought to be primarily due to blood flow stasis. Classically, the thromboembolism lodges at the iliac trifurcation of the aorta, occluding either one or both of the common iliac arteries. Because this split is called the saddle, and is the most frequent location for the thrombus, FATE is commonly known as saddle thrombus.&lt;ref&gt;{{cite web|url=https://www.mspca.org/angell_services/the-fragile-fate-of-fates-the-management-and-prognosis-of-feline-aortic-thromboembolism/|title=The Fragile Fate of FATEs: The Management and Prognosis of Feline Aortic Thromboembolism|publisher=Massachusetts Society for the Prevention of Cruelty to Animals-Angell|access-date=8 October 2016|archive-url=https://web.archive.org/web/20181009013329/https://www.mspca.org/angell_services/the-fragile-fate-of-fates-the-management-and-prognosis-of-feline-aortic-thromboembolism/|archive-date=9 October 2018|url-status=live}}&lt;/ref&gt; Clinically this presents as a cat with complete loss of function in one or both hind limbs. The hind limbs are cold and the cat is in considerable pain. Emboli may, rarely, lodge in other locations, most commonly the right front limb and the renal arteries.{{citation needed|date=February 2021}}

[[Clopidogrel]] is used to try to prevent left atrial thrombus formation in cats with hypertrophic cardiomyopathy and a large left atrium. The FATCAT study at Purdue University demonstrated that it is superior to aspirin for the prevention of a second thrombus from forming in cats that have already experienced a clot. Thrombolytic agents (e.g., tissue plasminogen activator) have been used with some success to break down existing aortic thromboembolism, but their cost is high and the outcome appears to be no better than giving a cat time (48–72 hours) to break down its own clot. Pain management is extremely important. The prognosis for cats with FATE is often poor as they are likely to have significant hypertrophic cardiomyopathy already and a recurrent bout of FATE is likely.&lt;ref&gt;{{cite journal | vauthors = Borgeat K, Wright J, Garrod O, Payne JR, Fuentes VL | title = Arterial thromboembolism in 250 cats in general practice: 2004-2012 | journal = Journal of Veterinary Internal Medicine | volume = 28 | issue = 1 | pages = 102–108 | year = 2014 | pmid = 24237457 | pmc = 4895537 | doi = 10.1111/jvim.12249 }}&lt;/ref&gt; For this reason, euthanasia is often a valid consideration.{{citation needed|date=February 2021}}

=== Gorillas ===
In July 2013, Rigo, a 42-year-old [[western lowland gorilla]], resident in [[Melbourne Zoo]] and father of Mzuri, the first gorilla born by [[artificial insemination]], died unexpectedly as a result of hypertrophic cardiomyopathy. The condition is not uncommon in male gorillas over the age of 30, and in many cases, there is no sign of the disease until the individual's sudden death.&lt;ref&gt;{{cite news| vauthors = Smith B |title=Silverback gorilla Rigo died of heart failure at Melbourne Zoo|url=http://www.theage.com.au/environment/animals/silverback-gorilla-rigo-died-of-heart-failure-at-melbourne-zoo-20130726-2qoyo.html|access-date=26 July 2013|newspaper=The Age|date=26 July 2013|archive-url=https://web.archive.org/web/20170103094057/http://www.theage.com.au/environment/animals/silverback-gorilla-rigo-died-of-heart-failure-at-melbourne-zoo-20130726-2qoyo.html|archive-date=3 January 2017|url-status=live}}&lt;/ref&gt;

== References ==
{{Reflist}}

== External links ==
* [https://www.ncbi.nlm.nih.gov/books/NBK1768/  GeneReviews/NIH/NCBI/UW entry on Familial Hypertrophic Cardiomyopathy Overview]
* [https://www.nhlbi.nih.gov/health/cardiomyopathy National Heart, Blood, and Lung Institute Cardiomyopathy Page]

{{Medical resources
| DiseasesDB      = 6373
| ICD11           = {{ICD11|BC43.1 }} 
| ICD10           = {{ICD10|I|42|1|i|30}}–{{ICD10|I|42|2|i|30}}
| ICD9            = {{ICD9|425.1}}
| ICDO            =
| OMIM            = 192600
| MedlinePlus     = 000192
| eMedicineSubj   = med
| eMedicineTopic  = 290
| eMedicine_mult  = {{eMedicine2|ped|1102}} {{eMedicine2|radio|129}}
| MeshID          = D002312
| Orphanet        = 217569
}}
{{Circulatory system pathology}}
{{Cytoskeletal defects}}
{{Portal bar | Medicine}}
{{Authority control}}

{{DEFAULTSORT:Hypertrophic Cardiomyopathy}}
[[Category:Articles containing video clips]]
[[Category:Autosomal dominant disorders]]
[[Category:Cardiogenetic disorders]]
[[Category:Cardiomyopathy]]
[[Category:Cat diseases]]
[[Category:Cytoskeletal defects]]
[[Category:Sports medicine]]
[[Category:Wikipedia medicine articles ready to translate]]