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HCM is caused by dysfunction in the cardiac sarcomere that causes excess myosin-actin cross-bridging, which leads to increased contractility, impaired relaxation, and increased energy consumption.5
In HCM, there is a thickening, or hypertrophy, of the left ventricular wall that cannot be explained by another cardiac, systemic, or metabolic disease.2
HCM has a diverse phenotypic presentation and can occur in 2 different forms, both of which can lead to adverse complications and outcomes.6,7
oHCM occurs when thickening of the ventricular
septum causes a dynamic narrowing that can
block or reduce blood flow from the LV to the aorta.
LV outflow tract (LVOT) obstruction is an important
component of this form of the disease and may
involve the mitral valve.7
LV=left ventricle; SAM=systolic anterior motion.
In nHCM, cardiac wall thickening occurs without
restricting blood flow.7
The reported prevalence of HCM ranges from
1 in 200 to
1 in 500
people in the general
The 1995 CARDIA study, a multicenter, US-population-based echocardiography study of 4111 subjects (aged 23-35) identified the prevalence of HCM as 1:500 people in the general population.3
The 2015 Semsarian publication identified that the prevalence of HCM gene carriers could be as high as 1:200.4
Only ~100,000‡ patients in the US have been diagnosed with HCM, which suggests that
85% to 94%
may remain undiagnosed.3,9§
Based on 2013 ICD-9 claims data.9
Estimated undiagnosed range calculated using prevalence range of 1:200 to 1:500, estimated US population (332,330,571 in May 2021), and estimated diagnosed population (~100,000).3,4,9,10
HCM can be genetically passed down from one generation to the next in some patients.2 HCM frequently remains undiagnosed until young adulthood and even as late as midlife, allowing disease progression to go unmitigated.11
more likely to
more frequent in
patients with AFib12
Based on the study AFib prevalence of 22% (107/480) and incidence of 2% new cases annually.12
of patients with HCM
developed heart failure13,14¶
A retrospective analysis of 4591 patients with HCM (63% male; median age at diagnosis: 45.8 years; median follow-up: 2.9 years) from the SHaRe Registry found a prevalence of 22%. A prospective, single-center observational study of ~1000 consecutive patients with HCM (63% male; age at diagnosis [years ±SD: 43±18]; median follow-up: 6.6 years) found a prevalence of 43%.13,14
All-cause mortality risk was substantially higher in
both younger and older patients with HCM than
that of the general population at US sites14#:
fold higher for
Sudden cardiac death (SCD) is uncommon, occurring in ~1% of patients with HCM14
Mortality rates for the general US population were based on 1999 to 2014 data from the Centers for Disease Control and Prevention WONDER database.14
Identification and monitoring of HCM can be challenging due to a variety of factors, such as11,15-17:
Patients with HCM are commonly asymptomatic or minimally symptomatic
Symptoms progress gradually and the presentation of the disease can vary across patients
Patients may subtly adapt their lifestyles to accommodate for the symptoms
CAD=coronary artery disease; COPD=chronic obstructive pulmonary disease.
Two different imaging methods can be used to establish an HCM diagnosis: Echocardiography is the primary modality for most patients, and cardiac magnetic resonance (CMR) imaging provides complementary information or an alternative option in cases where an echocardiogram is inconclusive.2
HCM diagnosis in adults, conventionally established through cardiac imaging, is based on unexplained
LV hypertrophy (LV wall thickness of ≥15 mm, or 13-14 mm with a family history of HCM or in conjunction with
a positive genetic test).2
Left ventricular outflow tract obstruction is a critical feature of oHCM associated with adverse HCM-related outcomes but can sometimes only be seen in some patients when provoked with exercise.2,23,24
Echos with provocation can reveal the structural and functional abnormalities consistent with HCM.2
In the absence of large, randomized clinical trials, the American Heart Association (AHA)/American College of Cardiology Foundation (ACCF) guidelines recommend pharmacologic therapy to alleviate HCM symptoms solely on an empirical basis.2,25
Current pharmacologic treatment options, such as beta blockers (non-vasodilating) and calcium channel blockers (non-dihydropyridine), were not developed for HCM and are typically indicated for other cardiovascular disorders, yet they may help relieve HCM symptoms. Patients with HCM who do not respond to beta blockers or non-dihydropyridine calcium channel blockers are candidates for more advanced therapies, such as disopyramide and septal reduction therapy (SRT).2
Some obstructive HCM patients who are symptomatic despite pharmacological treatment should be considered for surgical intervention, such as septal myectomy, or an invasive procedure such as alcohol septal ablation. In even more advanced stages, heart transplantation may be an option.18 Patients who require a septal myectomy may still have symptoms that require pharmacologic management, or they may need further surgical intervention.2,26,27
Given that disease progression is generally slow in HCM, patients experiencing symptoms may adapt to their disease and accept limitations without thinking to inform their healthcare provider.1,17 This can lead to unmanaged symptoms and lifestyle changes that negatively affect their emotional state and social functioning.28
Discussing HCM symptoms and monitoring the impact HCM has on patients’ physical, emotional, and psychological functioning is an important part of clinical assessments of disease severity and progression.2 Given the multiple aspects of lifestyle HCM can impact, an open conversation with patients continued over multiple visits can be helpful in establishing effective management.1
Naidu SS, ed. Hypertrophic Cardiomyopathy. London, Eng: Springer-Verlag; 2015.
Ommen SR, Mital S, Burke MA, et al. 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. Circulation. 2020;142(25):e533-e631.
Maron BJ, Gardin JM, Flack JM, Gidding SS, Kurosaki TT, Bild DE. Prevalence of hypertrophic cardiomyopathy in a general population of young adults. Echocardiographic analysis of 4111 subjects in the CARDIA study. Circulation. 1995;92(4):785-789.
Semsarian C, Ingles J, Maron MS, Maron BJ. New perspectives on the prevalence of hypertrophic cardiomyopathy. J Am Coll Cardiol.
Garfinkel AC, Seidman JG, Seidman CE. Genetic pathogenesis of hypertrophic and dilated cardiomyopathy. Heart Fail Clin. 2018;14(2):139-146.
Rowin EJ, Maron MS. The role of cardiac MRI in the diagnosis and risk stratification of hypertrophic cardiomyopathy. Arrhythm Electrophysiol Rev. 2016;5(3):197-202.
Stanford Health Care. Hypertrophic cardiomyopathy. Accessed June 14, 2021. https://stanfordhealthcare.org/medical-conditions/blood-heart-circulation/hypertrophic-cardiomyopathy.html
Maron BJ, Rowin EJ, Maron MS. Global burden of hypertrophic cardiomyopathy. JACC Heart Fail. 2018;6(5):376-378.
Maron MS, Hellawell JL, Lucove JC, Farzaneh-Far R, Olivotto I. Occurrence of clinically diagnosed hypertrophic cardiomyopathy in the
United States. Am J Cardiol. 2016;117(10):1651-1654.
United States Census Bureau. U.S. and world population clock. Accessed April 23, 2021. www.census.gov/popclock
Jacobs C. Hypertrophic cardiomyopathy in adults: an overview. J Am Assoc Nurse Pract.
Olivotto I, Cecchi F, Casey SA, Dolara A, Traverse JH, Maron BJ. Impact of atrial fibrillation on the clinical course of hypertrophic
cardiomyopathy. Circulation. 2001;104(21):2517-2524.
Rowin EJ, Maron MS, Chan RH, et al. Interaction of adverse disease related pathways in hypertrophic cardiomyopathy. Am J Cardiol.
Ho CY, Day SM, Ashley EA, et al; SHaRe Investigators. Genotype and lifetime burden of disease in hypertrophic cardiomyopathy: insights
from the Sarcomeric Human Cardiomyopathy Registry (SHaRe). Circulation. 2018;138(14):1387-1398.
Mayo Clinic. Hypertrophic cardiomyopathy. June 2, 2020. Accessed April 28, 2021. https://
Maron BJ, Towbin JA, Thiene G, et al. Contemporary definitions and classification of the cardiomyopathies: an American Heart Association Scientific Statement from the Council on Clinical Cardiology, Heart Failure and Transplantation Committee; Quality of Care and Outcomes Research and Functional Genomics and Translational Biology Interdisciplinary Working Groups; and Council on Epidemiology and Prevention. Circulation. 2006;113(14):1807-1816.
Jacoby DL, DePasquale EC, McKenna WJ. Hypertrophic cardiomyopathy: diagnosis, risk stratification and treatment. CMAJ. 2013;185(2):127-134.
Marian AJ, Braunwald E. Hypertrophic cardiomyopathy: genetics, pathogenesis, clinical manifestations, diagnosis, and therapy. Circ Res. 2017;121(7):749-770.
Wexler RK, Elton T, Pleister A, Feldman D. Cardiomyopathy: an overview. Am Fam Physician. 2009;79(9):778-784.
Argulian E, Sherrid MV, Messerli FH. Misconceptions and facts about hypertrophic cardiomyopathy. Am J Med. 2016;129(2):148-152.
Fifer MA, Vlahakes GJ. Management of symptoms in hypertrophic cardiomyopathy. Circulation. 2008;117(3):429-439.
University of Maryland Medical Center. Hypertrophic cardiomyopathy types, symptoms and causes. Accessed June 14, 2021. https://www.umms.org/
Patel P, Dhillon A, Popovic ZB, et al. Left ventricular outflow tract obstruction in hypertrophic cardiomyopathy patients without severe septal hypertrophy: implications of mitral valve and papillary muscle abnormalities assessed using cardiac magnetic resonance and echocardiography. Circ Cardiovasc Imaging. 2015;8(7):e003132.
Maron MS, Olivotto I, Zenovich AG, et al. Hypertrophic cardiomyopathy is predominantly a disease of left ventricular outflow tract obstruction. Circulation. 2006;114(21):2232-2239.
Elliott PM, Anastasakis A, Borger MA, et al. 2014 ESC Guidelines on Diagnosis and Management of Hypertrophic Cardiomyopathy: The Task Force for the Diagnosis and Management of Hypertrophic Cardiomyopathy of the European Society of Cardiology (ESC). Eur Heart J. 2014;35(39):2733-2779.
Liebregts M, Vriesendorp PA, Mahmoodi BK, Schinkel AF, Michels M, ten Berg JM. A systematic review and meta-analysis of long-term
outcomes after septal reduction therapy in patients with hypertrophic cardiomyopathy. JACC Heart Fail. 2015;3(11):896-905.
Minakata K, Dearani JA, Schaff HV, O’Leary PW, Ommen SR, Danielson GK. Mechanisms for recurrent left ventricular outflow tract
obstruction after septal myectomy for obstructive hypertrophic cardiomyopathy. Ann Thorac Surg.
Sweeting J, Ingles J, Timperio A, Patterson J, Ball K, Semsarian C. Physical activity in hypertrophic cardiomyopathy: prevalence of inactivity and perceived barriers. Open Heart. 2016;3(2):e000484.
Ammirati E, Contri R, Coppini R, Cecchi F, Frigerio M, Olivotto I. Pharmacological treatment of hypertrophic cardiomyopathy: current practice and novel perspectives. Eur J Heart Fail. 2016;18(9):1106-1118.
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