Hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy is an autosomal dominant sarcomere disease causing unexplained left ventricular hypertrophy, often with dynamic left ventricular outflow tract obstruction, and is a leading cause of sudden cardiac death in young people. Diagnosis is by echocardiography or cardiac MRI showing unexplained hypertrophy, and management includes negative inotropes, obstruction relief, and ICD placement for high sudden-death risk.
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What this article covers
- Overview
Definition: hypertrophic cardiomyopathy (HCM) is an autosomal dominant disorder of sarcomere genes causing left ventricular hypertrophy not explained by loading conditions.
- Epidemiology
The most common inherited cardiomyopathy, affecting roughly 1 in 500.
- Risk factors
Sarcomere gene mutation / family history: the underlying cause (for example MYH7, MYBPC3).
- Pathophysiology
Sarcomere dysfunction: mutations cause myocyte hypertrophy and disarray with interstitial fibrosis.
- Clinical features
Symptoms: exertional dyspnea, angina, palpitations, presyncope, and syncope; sudden death may be the first event.
- Differential diagnosis
Aortic stenosis: a harsh systolic ejection murmur radiating to the carotids, distinguished from HCM by softening with Valsalva and a calcified valve with a fixed gradient on echocardiography (aortic stenosis).
- Diagnosis
Establish with imaging showing unexplained left ventricular hypertrophy plus assessment of obstruction and sudden-death risk: the diagnostic basis is echocardiography (or cardiac MRI) demonstrating a…
- Management
First, relieve obstruction and symptoms with negative inotropes: Metoprolol 50 mg PO twice daily as first-line, titrated to heart rate and symptoms.
- Complications
Sudden cardiac death from ventricular arrhythmia (sudden cardiac arrest).
- Prognosis
Many live normally, but sudden death is the feared outcome, largely preventable by ICD in high-risk patients.
- Prevention
Identify and protect high-risk patients with an ICD.
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Related articles
- Sudden cardiac arrest
Sudden cardiac arrest is the abrupt cessation of cardiac function with loss of pulse and consciousness, most often from a ventricular tachyarrhythmia on a background of coronary disease. Survival depends on immediate CPR and defibrillation of shockable rhythms, followed by treatment of the cause and secondary prevention with an ICD.
- Heart failure
Heart failure is a clinical syndrome of impaired cardiac filling or ejection causing congestion and reduced perfusion, classified by ejection fraction. Diagnosis integrates symptoms, signs, natriuretic peptides, and echocardiography, and treatment of reduced-ejection-fraction disease is quadruple guideline-directed therapy, with device therapy and cause-specific management.
- Aortic stenosis
Aortic stenosis is obstruction to left ventricular outflow from a narrowed aortic valve, most often calcific degeneration in older adults or a bicentric bicuspid valve earlier in life. Symptoms of angina, syncope, or heart failure mark a poor prognosis, and severe symptomatic disease is treated with valve replacement (surgical or transcatheter).