Diagnosing Hypertrophic Cardiomyopathy1
Findings during a clinical assessment that may raise suspicion of HCM include6:
Family history
Symptoms, including
a cardiac event
Electrocardiogram
abnormalities*
Detection of
a heart murmur†
*Electrocardiogram abnormalities: Although no ECG pattern is specific to HCM, anomalies consistent with HCM include ST- and T-wave changes, pathological Q waves, increased QRS voltages and deep T-wave inversion.7
†Heart murmur: Best heard over left sternal border and becomes louder with maneuvers that increase pre-load or afterload.7
Once HCM is suspected, an
evaluation should start with6:
Thorough
cardiac history
3-generation
family history
A more
comprehensive
physical exam‡
Echocardiogram
‡Physical exam: Including Valsalva maneuver, squat-to-stand, passive leg raising, and/or walking. This can be critical because signs of HCM may not be visible at rest.
Diagnosing HCM
Dr. Owens and Dr. Silvestri describe their approaches to differential diagnosis.
Diagnosing HCM6
Once HCM is suspected, cardiac imaging is essential for diagnosis. Echocardiography is the primary imaging modality to examine HCM and determine:
- Maximal LV wall thickness (in the absence of another cause of hypertrophy) of ≥15 mm or 13–14 mm with a family history of HCM or positive genetic test
- Presence, location, and severity of LVOT obstruction, both at rest and with provocation (eg, Valsalva)
- Obstruction is defined as LVOT peak gradient ≥30 mmHg with or without provocation
- Need for genetic testing of other family members at risk for developing HCM
About 2/3 of Patients With HCM Have Obstruction6,8,9
Assessment of LVOT gradient is critical to properly distinguish obstructive vs nonobstructive HCM—which have distinct pathophysiology, clinical risks, and treatment.
Resting echocardiography often underestimates LVOT gradients, potentially missing up to 50% of obstructive cases
For patients with a resting LVOT <50 mmHg, an echo with provocation, such as Valsalva or exercise stress is recommended6,8
A
Isolated basal septal
B
Reversed septal curvature
C
Apical
D
Mid cavity
E
Concentric/neutral
Videos A-D from Nagueh SF, et al. Supplementary data: video 1. J Am Soc Echocardiogr. 2022;35(6):533-569. Accessed June 3, 2024. https://www.onlinejase.com/article/S0894-7317(22)00140-7/fulltext#supplementaryMaterial. Courtesy of Dr John Symanski, Sanger Heart and Vascular Institute. Atrium Health, Charlotte, NC. Concentric LVH echo clip provided by a US healthcare provider.
When echo findings are inconclusive, cardiac magnetic resonance imaging (CMR) can be an additional tool for visualization and quantification of myocardial abnormalities. CMR can also help determine the type and presentation of HCM.6
REFERENCES:
- Stanford Health Care. Hypertrophic cardiomyopathy. Accessed June 14, 2021. https://stanfordhealthcare.org/medical-conditions/blood-heart-circulation/hypertrophic-cardiomyopathy.html
- 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.
- Jacobs C. Hypertrophic cardiomyopathy in adults: an overview. J Am Assoc Nurse Pract. 2014;26(9):465-470.
- Mayo Clinic. Hypertrophic cardiomyopathy. June 2, 2020. Accessed April 28, 2021. https://www.mayoclinic.org/diseases-conditions/hypertrophic-cardiomyopathy/symptoms-causes/syc-2035019
- 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 Heart Association/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.
- Nagueh SF, Phelan D, Abraham T, et al. Recommendations for multimodality cardiovascular imaging of patients with hypertrophic cardiomyopathy: an update from the American Society of Echocardiography, in collaboration with the American Society of Nuclear Cardiology, the Society for Cardiovascular Magnetic Resonance, and the Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2022;35(6):533-569.
- Mitchell CC, Frye C, Jankowski M, et al. A practical approach to echocardiographic imaging in patients with hypertrophic cardiomyopathy. J Am Soc Echocardiogr. 2023;36(9):913-932.
- Neubauer S, Kolm P, Ho CY, et al. Distinct subgroups in hypertrophic cardiomyopathy in the NHLBI HCM Registry. J Am Coll Cardiol. 2019;74(19):2333-2345.
- 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.