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Hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy is a genetic heart-muscle disease with a wall thickness of 15 mm or more, which in some patients obstructs the left-ventricular outflow; treatment reduces the obstruction, and the most important question is the risk of sudden death.
Why it matters in the exam
The exam tests the murmur and the manoeuvres: a systolic murmur that gets louder on standing and with Valsalva (less blood in the ventricle, more obstruction) and softer with squatting and handgrip. Candidates are also asked what must not be given — vasodilators, nitrates, high-dose diuretics and digoxin, which increase obstruction — and what is given: a beta-blocker, then verapamil or diltiazem, disopyramide, and a cardiac myosin inhibitor (mavacamten).
Many questions are about sudden death: who needs an ICD (secondary prevention after cardiac arrest or sustained VT; primary prevention by risk factors — family sudden death, unexplained syncope, a septum at least 30 mm thick, runs of non-sustained VT, an apical aneurysm, EF below 50% and extensive MRI enhancement). Screening of first-degree relatives (ECG, echo and genetic testing), the distinction from the "athlete's heart", and atrial fibrillation — in which anticoagulation is given regardless of the CHA2DS2-VASc score — are also asked.
In a patient with obstruction and symptoms despite drug treatment, and a gradient of 50 mmHg or more, septal reduction is offered — surgical myectomy or alcohol septal ablation. The disease is not an indication for endocarditis prophylaxis.
Key points
- Diagnosis: wall thickness 15 mm or more (13 in a relative).
- The murmur gets louder on standing and with Valsalva, and softer with squatting.
- Treatment: beta-blocker, then verapamil/diltiazem, disopyramide or mavacamten; septal reduction if refractory.
- ICD after cardiac arrest or VT, and for primary prevention by risk factors.
- Atrial fibrillation — always anticoagulate; screen first-degree relatives.
Summary table
| Item | The rule | Details | Trap |
|---|---|---|---|
| Diagnosis | Wall thickness 15 mm or more without another cause | 13 mm or more in a relative of a patient | Echo and MRI; genetic testing |
| Outflow obstruction | Gradient 30 mmHg or more at rest or on provocation | Significant from 50 mmHg | Valsalva and standing increase it; squatting reduces it |
| Symptom treatment | Beta-blocker, then verapamil/diltiazem, disopyramide, mavacamten | Septal reduction for refractory symptoms with a gradient of 50 or more | No nitrates, no vasodilators, no digoxin |
| Preventing sudden death | ICD after cardiac arrest or sustained VT | Primary prevention by risk calculator and risk factors | Unexplained syncope is an important risk factor |
| Atrial fibrillation | Always anticoagulate | Regardless of CHA2DS2-VASc | DOAC |
| Family | Screen first-degree relatives | ECG, echo, genetic testing | Autosomal dominant inheritance |
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Sources
- ESC Guidelines for the management of cardiomyopathies, 2023 — Hypertrophic cardiomyopathy: diagnosis, obstruction, sudden-death risk and family screening
- AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy, 2024 — Medical therapy and septal reduction
- Harrison's Principles of Internal Medicine, 21st edition (2022) — Cardiomyopathy and Myocarditis
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.