Obstructive HCM Can Result in Structural Changes That Significantly Impact Patients Over Time1,2
Explore this page: | Driven by Myosin-Actin | Changes in Cardiac Structure | Consequences of Changes | Years of Burden in Adolescents
Obstructive HCM is a chronic, progressive disease characterized by hypercontractility, driven by excess myosin-actin cross-bridges3,4
Wall thickening leads to structural and functional changes in the heart1,2,5
Echo Images provided by a US HCP.
Changes to cardiac structure–including LVOT obstruction—can lead to symptoms that can significantly impact quality of life1,2,6
Chest pain
Fatigue
Exertional dyspnea
Palpitations
Dizziness
Syncope
Until recently, treatments have mostly been evaluated in nonrandomized trials1
Prior to cardiac myosin inhibitors, standard-of-care treatments included:
- Primarily symptom management with BBs, CCBs, or disopyramide1
- Invasive SRT, recommended to be performed in highly qualified* treatment centers1
| * | Primary or comprehensive HCM treatment centers.1 |
BB=beta blocker; CCB=calcium channel blocker; HCM=hypertrophic cardiomyopathy; HCP=healthcare provider; LV=left ventricle; LVEF=left ventricular ejection fraction; LVOT=left ventricular outflow tract; NT-proBNP=N-terminal pro–B-type natriuretic peptide; SRT=septal reduction therapy.
The consequences of cardiac structure changes in obstructive HCM extend beyond symptoms1
Over time, structural changes can occur, and progressive disease may lead to7,8:
AFib
19%–20%†
of patients7,8
NYHA Class III/IV
heart failure
43%†
of patients7
Stroke or other systemic
thromboembolism
6%‡
of patients9
Mortality
(sudden cardiac death)
<1%†
of patients/year8
| † | Based on a retrospective analysis from the SHaRe registry (N=4591) and a prospective, single-center US observational study from 2003–2013 (N=1000).7,8 |
| ‡ | Based on a four-center observational study in the US and Italy (N=900).9 |
Approximately 2/3 of patients with HCM have obstruction1,10
Resting echocardiography tends to underestimate LVOT gradients, potentially missing up to 50% of obstructive cases.1
For patients diagnosed early in life, the burden of obstructive HCM may extend for decades11,12
A greater burden of risk
36% greater likelihood of ventricular arrhythmias that can be life-threatening vs adult-onset HCM§11
Potential for a worse prognosis than adult-onset
~2x the risk of heart transplantation or sudden cardiac death compared to adult-onset HCM12
A possible need for major surgery at a young age
~7% to 23% of children with HCM undergo cardiac myectomy12
Patients diagnosed early in life deserve a treatment approach that targets obstruction
| § | Based on the observational HCM SHaRe registry (n=7677), including 1312 pediatric patients (<1 year–18 years).11 |
Provocative maneuvers can help uncover the presence of obstruction1
- In patients with HCM who have a resting LVOT gradient <50 mmHg, provocative maneuvers such as Valsalva are recommended by the 2024 AHA/ACC/MS HCM Guideline1
- In addition to Valsalva, other provocative maneuvers include
- Standing
- Squat-to-stand
- Exercise
To identify obstructive physiology, the 2024 AHA/ACC/MS Guideline recommends establishing the presence of obstructive HCM through imaging1
- ≥15 mm wall thickening in the left ventricle (in the absence of another cause of hypertrophy) is required for a clinical diagnosis
- 13–14 mm is required in conjunction with a family history of HCM or a positive genetic test
Per the guideline, obstruction is defined as LVOT peak gradient ≥30 mmHg with or without provocation1
- Assessment of LVOT gradients can help differentiate between HCM subtypes (ie, obstructive vs nonobstructive)1
- Genetic testing is beneficial to facilitate the identification of family members at risk for developing HCM1
ACC=American College of Cardiology; AFib=atrial fibrillation; AHA=American Heart Association; HCM=hypertrophic cardiomyopathy; LVOT=left ventricular outflow tract; MS=multisociety; NYHA=New York Heart Association; SHaRe=Sarcomeric Human Cardiomyopathy Registry.
Current treatments for symptomatic obstructive HCM
Conventional1
The role of treatment options recommended in the AHA/ACC/MS Guideline is primarily that of symptom management. Due to limited evidence from randomized controlled trials, management is often based on nonrandomized or limited data.
Cardiac Myosin Inhibitors1,13,14
FDA-approved therapy that targets cardiac myosin, recommended as a Class 1 treatment in AHA/ACC/MS Guideline for patients with persistent symptoms on 1L therapy.§
Invasive1
Guideline-recommended septal reduction therapy for patients whose symptoms are not relieved by 1L pharmacological therapy.§
| § | Symptoms include effort-related dyspnea or chest pain and occasionally other exertional symptoms (eg, syncope, near syncope) that are attributed to LVOTO and interfere with everyday activity or quality of life despite beta blocker or nondihydropyridine calcium channel blocker.1 |
| 1L=first-line; ACC=American College of Cardiology; AHA=American Heart Association; FDA=US Food and Drug Administration; HCM=hypertrophic cardiomyopathy; LVOTO=left ventricular outflow tract obstruction; MS=multisociety. |
Consider the next step—complement conventional therapy with CAMZYOS13
References:
- Ommen SR, Ho CY, Asif IM, et al. 2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American HeartAssociation/American College of Cardiology Joint Committee on Clinical Practice Guidelines. Circulation. 2024;149(23):e1239-e1311.
- Naidu SS, Sutton MB, Gao W, et al. Frequency and clinicoeconomic impact of delays to definitive diagnosis of obstructive hypertrophic cardiomyopathy in the United States. J Med Econ. 2023;26(1):682-690.
- Olivotto I, Oreziak A, Barriales-Villa R, et al. Mavacamten for treatment of symptomatic obstructive hypertrophic cardiomyopathy (EXPLORER-HCM): a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet. 2020;396(10253):759-769.
- Anderson RL, Trivedi DV, Sarkar SS, et al. Deciphering the super relaxed state of human β-cardiac myosin and the mode of action of mavacamten from myosin molecules to musclefibers. Proc Natl Acad Sci USA. 2018;115(35):E8143-E8152.
- Olivotto I, Cecchi F, Poggesi C, et al. Patterns of disease progression in hypertrophic cardiomyopathy: an individualized approach to clinical staging. Circ Heart Fail. 2012;5(4):535-46.
- Stanford Health Care. Hypertrophic cardiomyopathy. Accessed October 7, 2026. https://stanfordhealthcare.org/medical-conditions/blood-heart-circulation/hypertrophic-cardiomyopathy.html
- Rowin EJ, Maron MS, Chan RH, et al. Interaction of adverse disease related pathways in hypertrophic cardiomyopathy. Am J Cardiol. 2017;120(12):2256-2264.
- Ho CY, Day SM, Ashley EA, et al. Genotype and lifetime burden of disease in hypertrophic cardiomyopathy. Circulation. 2018;138(14):1387-1398.
- Maron BJ, Olivotto I, Bellone P, et al. Clinical profile of stroke in 900 patients with hypertrophic cardiomyopathy. J Am Coll Cardiol. 2002;39(2):301-307.
- 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.
- Marston NA, Han L, Olivotto I, et al. Clinical characteristics and outcomes in childhood-onset hypertrophic cardiomyopathy. Eur Heart J. 2021;42(20):1988-1996.
- Rossano JW, Canter C, Wolf CM, et al. Mavacamten in adolescents with obstructive hypertrophic cardiomyopathy. N Engl J Med. 2026;395(4):362-373.
- CAMZYOS [package insert]. Princeton, NJ: Bristol-Myers Squibb Company; 2026.
- Garcia-Pavia P, Oręziak A, Masri A, et al. Long-term effect of mavacamten in obstructive hypertrophic cardiomyopathy. Eur Heart J. 2024;45(47):5071-5083.