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Hypertrophic cardiomyopathy: Suspect-and-test checklist for clinicians

A one-page worksheet that turns the full Hypertrophic cardiomyopathy diagnosis guide into something you can use at the point of care: what to look for, what to order, which results should not end the workup, and who else to test or refer.

Who it is forClinicians and care teams who may see Hypertrophic cardiomyopathy before it is diagnosed, including primary care, the specialists named in the guide, and referral or genetics coordinators.
When to use itWhen Hypertrophic cardiomyopathy is on the differential, when a patient has several red flags, or when you are preparing a referral or a second opinion.

How to use it, section by section

  1. Red flags present: Tick each finding the patient has. They are grouped by body system so you can scan quickly.
  2. Already labeled as: Tick earlier diagnoses on the chart that the sources say are often given first.
  3. Family to test: Note relatives who may need testing, and record when symptoms began and which specialists have already been seen.
  4. Testing, in order: Tick each test as you order it and write the result on its line. The order follows the published sources.
  5. Results that do not rule it out: A reminder of findings that can look reassuring but do not exclude Hypertrophic cardiomyopathy.
  6. Specialists: Tick the referral, then write who it went to and any notes.
Two ways to fill it inPrint it blank and write on it, or tick boxes and type on this screen first, then print or save as a PDF. Keep it with the chart or send it with the referral.
PrivacyNothing you type is sent or saved. It stays in this browser tab and disappears when you close it. Use patient initials, not full identifiers.

What it is not: Not a diagnostic score, a protocol or coding advice. It summarizes published sources, and clinical judgment and the treating clinician govern. Every point is sourced in the full Hypertrophic cardiomyopathy guide.

One Letter page. Use your browser's print or save as PDF.Full guide with sources
Suspect-and-test checklist
Hypertrophic cardiomyopathy

Heritable thickening of the heart muscle with no other cause. Start from a murmur that changes with Valsalva or standing, an abnormal ECG, exertional symptoms or an affected relative.

ICD-10-CMI42.1, I42.2Trial Friend for Clinicians

1Red flags present

Symptoms and history

Examination

ECG

Echocardiogram and MRI

Family

Clues to a mimic

2Already labeled as

3Family to test

4Testing, in the order the sources describe

  1. Family history, symptoms and risk historyThree generations: known HCM, murmur, sudden death. Ask about syncope and cardiac arrest.
    Result
  2. Examination with provocative maneuversMurmur increases with Valsalva and standing from a squat; 5 to 20 squat-to-stand repetitions.
    Result
  3. 12-lead ECGAbnormal in about 90%. Hypertrophy voltage, deep lateral T-wave inversions, deep Q waves, pre-excitation.
    Result
  4. Transthoracic echocardiogramAHA/ACC 2024 (as reported by Sanghvi 2025): 15mm or more in adults; 13 to 14mm with an affected relative or a pathogenic variant.
    Result
  5. Doppler outflow gradientObstruction is 30mmHg or more; 50mmHg generally needed to cause symptoms.
    Result
  6. Provocation, then exercise echocardiographyAHA/ACC 2024 (as reported by Sanghvi 2025): provocative maneuvers if resting gradient is under 50mmHg; exercise echo if symptomatic and still under 50mmHg.
    Result
  7. Cardiac MRIAHA/ACC: when echo is inconclusive or a mimic is suspected. ESC: at initial evaluation for all (both as reported by Sanghvi 2025).
    Result
  8. Z-scores in childrenAt least 2 standard deviations with family history or a positive genetic test; 2.5 or more without.
    Result
  9. Work-up for mimicsAtypical presentation: genetic testing for HCM and other genetic causes of hypertrophy.
    Result
  10. Genetic counseling and testingNot required for diagnosis. Pathogenic or likely pathogenic variant in 30% to 40%.
    Result
  11. Sudden death risk assessmentAHA/ACC 2024 (as reported by Sanghvi 2025): at first evaluation and every 1 to 2 years, using the guideline's listed risk factors.
    Result
  12. Echocardiogram before a cardiac myosin inhibitorCamzyos label: ejection fraction before and during treatment; REMS program.
    Result

5Results the sources say do not rule it out

  • No gradient at rest. Of 201 patients under 50mmHg at rest, 106 obstructed after exercise.
  • Negative Valsalva. It underestimated exercise-induced obstruction.
  • Normal ECG. Found in almost 6% (Mayo Clinic) and 1.6% (Istanbul) of patients with HCM.
  • Normal routine echocardiogram without contrast when T waves are inverted. Apical HCM can be missed.
  • Negative genetic test. A causal variant was found in about 32% of 2912 probands.
  • A hypertension label. In one registry 28% of patients with HCM also had hypertension.
  • Wall under 15mm in a woman or at the apex. The threshold is not adjusted for sex or body size.
  • Systolic anterior motion alone. Also seen in Fabry disease, amyloidosis and under dobutamine.

6Specialists the sources name

Diagnosis codes: I42.1 Obstructive hypertrophic cardiomyopathy; I42.2 Other hypertrophic cardiomyopathyCodes patients often carry before diagnosis are listed in the online guide.
Full guide and sourcesEvery point here is sourced in the online guide, which also has a patient note to print.
Trial Friend, trialfriend.com/for-clinicians. Key sources: AHA/ACC HCM guideline 2024; Guideline systematic review (Sanghvi 2025); Mayo Clinic review (Gilreath 2026); ANMCO position paper 2025; US claims study of delay (Naidu 2023); CARDIA study (Maron 1995); all 29 with links in the online guide. Checked November 13, 2026. A reference checklist for licensed clinicians that summarizes published sources. It is not a diagnostic tool, a score or a protocol, and it does not replace clinical judgment, local practice or the prescribing information. Not coding advice. Trial Friend never receives anything written or typed on this sheet.