Hypertrophic Cardiomyopathy

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Definition Aetiology Pathophysiology Risk factor Sign and Symptoms Investigations Management

Hypertrophic cardiomyopathy (HCM) is a heart condition characterised by abnormally thickened heart muscle. This thickening can make it more difficult for the heart to effectively pump blood and may interfere with the normal function of the heart valves.

Hypertrophic cardiomyopathy (HCM) is caused by a genetic disorder. Typically, it is inherited as an autosomal dominant trait, which means that if one parent has the condition, there is a 50% chance that their child will also have it. The majority of cases of hypertrophic cardiomyopathy (HCM) are due to mutations in genes that code for proteins in the sarcomere, the basic contractile unit of the heart muscle.

Besides genetic factors, additional factors include:

• Chronic hypertension can cause thickening of the heart muscle because the heart has to work harder to pump blood against increased resistance.

• Ageing

• Metabolic or endocrine disorders: diabetes or thyroid disorders

• Intense and prolonged athletic training can cause a degree of heart muscle thickening that is typically reversible upon cessation of training.

The main feature of HCM is the abnormal thickening (hypertrophy) of the heart muscle, predominantly affecting the left ventricle, but it can also involve the right ventricle or both.

• Family history: HCM is frequently a dominant autosomal trait. If a close relative (parent, sibling, or child) has HCM, you have a greater chance of inheriting the mutated gene that causes the condition.

• Genetic mutations: Specific genetic mutations, particularly in genes encoding sarcomeric proteins, are associated with sarcoidosis.

• Hypertension.

• Increased age.

• Other medical conditions: such as diabetes or thyroid disorders.

• Intense exercise.

• Shortness of breath (SOB): this can occur at rest or can be exacerbated by physical exertion. This occurs because the heart cannot effectively fill and pump blood. This results in increased left atrial and pulmonary pressure.

• Chest pain: inadequate oxygen delivery to the heart muscle is the cause of chest pain.

• Fatigue

• Dizziness and in some cases fainting (syncope): generally caused by a decreased blood flow to the brain or abnormal heart rhythms (arrhythmias).

• Palpitations: Individuals may feel rapid, irregular, or forceful heartbeats, which may be caused by arrhythmias such as atrial fibrillation and ventricular tachycardia.

• Ankle/leg swelling: The retention of fluid in the legs, ankles, or feet (edoema) is caused by impaired heart function.

• O/E heart murmur: The presence of a heart murmur upon physical examination.

• Physical examination.

• Electrocardiogram (ECG).

• Echocardiogram.

• Cardiac magnetic resonance imaging (CMR).

• Holter monitoring.

• Genetic testing: this can be used to identify specific genetic mutations associated with HCM. 

• Cardiac catheterization.

• Blood tests: full blood count, electrolytes, kidney and liver function test.

Lifestyle modifications: physical activity, manage risk factors, adopt a heart-healthy diet

Medication: 

• Beta-blockers (e.g., bisoprolol, metoprolol, or atenolol) are frequently the first-line treatment for symptom reduction and improvement of exercise tolerance.

• Calcium channel blockers (e.g., verapamil or diltiazem) may be considered as an alternative or supplementary therapy for patients who cannot tolerate beta-blockers or who do not respond to them.

• Diuretics may be used to alleviate fluid retention and congestion in patients with heart failure.

• Antiarrhythmic drugs such as amiodarone can be used to treat atrial or ventricular arrhythmias..

• Warfarin or direct oral anticoagulants (DOACs), may be prescribed for patients with atrial fibrillation or a high risk of thromboembolic events.

Surgery: surgical excision of a portion of the thickened septum or septal ablation with alcohol (a procedure that uses alcohol to cause a controlled infarction of the thickened septum).

Implantable cardioverter-defibrillator (ICD).

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