| Thorough cardiac history: | Comprehensive physical exam, which includes |
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Diagnosis of HCM can be challenging
Genetic testing and family screening can help uncover hypertrophic cardiomyopathy (HCM)
- ~50% of patients have the hereditary genes that cause HCM, and yet many are unaware that they have it1-3
- Genetic testing can identify a disease-causing mutation in up to 60% of patients with HCM1,3
- Establishing a multigenerational (at least 3 generations) family history can help to confirm HCM and also identify family members at risk for disease1,3
2024 Canadian HCM Clinical Practice Update: Practical Tips4
Genetic testing:
- Genetic testing should be offered to all individuals with a clinical diagnosis of HCM:
- to exclude HCM “mimics”
- to facilitate family screening.
- Where a genetic variant has been identified, counselling and genetic testing should be offered to all relatives regardless of age.
Clinical screening:
- First-degree relatives of patients diagnosed with HCM: conduct baseline clinical screening with echocardiography and a resting ECG.
- Relatives who do not carry the variant can discontinue follow-up based on normal baseline clinical screening.
- Offer periodic clinical screening to:
- relatives with a genetic variant
- first-degree relatives of individuals with HCM diagnosis but genetic variant not identified.
Simplifying the steps to a nonobstructive vs. obstructive HCM diagnosis5
Exercise echocardiography predicts HF progression and dictates management decisions in HCM5
Modified with permission from Rowinet al.
Exercise echocardiography serves as a marker for disease progression since patients with provocable (labile) obstruction with exercise and no or only mild baseline symptoms develop advanced heart failure (HF) symptoms at a rate of 3.2% per year, exceeding that of nonobstructive patients (1.6% per year; p=0.002). Patients with provocable obstruction who develop drug-refractory limiting symptoms to New York Heart Association functional class III/IV become candidates for surgical myectomy (or selectively alcohol septal ablation) to reverse HF. Nonobstructive patients with functional class III/IV symptoms become heart transplant candidates.5
Source: Rowin EJ, et al. Exercise Testing in Hypertrophic Cardiomyopathy. JACC: Cardiovascular Imaging 2017;10(11):1374-86.
RECOGNIZE the signs
Potential indicators of HCM:
- Symptoms such as dyspnea, angina pectoris and exercise intolerance1,3
- An abnormal electrocardiogram1-3
- Systolic murmur1,3
EVALUATE clinically, once HCM is suspected1,3
CONFIRM with echocardiogram and cardiac magnetic resonance imaging, and determine if it’s obstructive1,3†
A stress echocardiogram is recommended because it can:
- Evaluate cardiac anatomy and see if other abnormalities are present3
- Accurately capture left ventricular outflow tract (LVOT) obstruction in HCM by measuring LVOT gradients1,3
- Provide a measure of the severity of gradient1,3
Recognize the constellation of signs and follow key diagnostic
methods to help identify HCM
Why do we need to identify obstruction?4
The identification of LVOT obstruction is fundamental to the management of HCM, because management of symptoms varies according to its presence/absence.
- LVOT obstruction most frequently results in symptoms of breathlessness, dizziness and chest pain of varying severity.
- Most patients with severe obstruction will have symptoms or objective evidence of decreased exercise capacity when measured, but a small percentage might be asymptomatic.
- Asymptomatic patients might develop symptoms later in life, even in the absence of progressive hypertrophy or worsening gradient; this might be due, in part, to progressive diastolic dysfunction.
Footnotes
* The Valsalva maneuver may induce signs of LVOT obstruction that may not be present while at rest.1,2
† Echocardiography is the primary modality for most patients, and cardiac magnetic resonance imaging offers complementary information or an alternative way to diagnose obstructive HCM.3
References
- Naidu, Srihari S, editor. Hypertrophic Cardiomyopathy. Second ed., Springer International Publishing, 2019.
- Gersh BJ, et al. 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy. J Thorac Cardiovasc Surg 2011;142(6):e153-203.
- Ommen SR, et al. 2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol 2024;83(23):2324-405.
- Crean AM, et al. General Clinical Practice Update: Canadian Cardiovascular Society Clinical Practice Update on Contemporary Management of the Patient with Hypertrophic Cardiomyopathy. Can J Cardiol 2024;40(9):1503-23.
- Rowin EJ, et al. Exercise Testing in Hypertrophic Cardiomyopathy. JACC: Cardiovascular Imaging 2017;10(11):1374-86.