Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is a hereditary condition, caused by mutation of genes coding for the component proteins of the heart muscle. This results in abnormally thick heart muscles, not caused by abnormal loading conditions (such as uncontrolled blood pressure, severe valvular heart disease). The prevalence of hypertrophic cardiomyopathy in the population is estimated to be 1 in 500, making it one of the most common genetic heart diseases.

• Shortness of breath
• Chest pain
• Palpitations
• Unexplained fainting spells
• Sudden cardiac arrest

Hypertrophic cardiomyopathy is diagnosed by cardiologists, by integrating various clinical information, including:

• Patient symptoms
• Clinical examination
  • Evaluation for presence of heart murmurs
• Electrocardiogram ('ECG')
  • Electrical tracing of the heart, looking for heart rhythm abnormalities, as well as signs of underlying structural heart abnormalities
• Echocardiogram
  • Ultrasound examination which allows doctors to measure the heart muscle thickness and assess for complications of hypertrophic cardiomyopathy
  • Exercises stress echocardiogram might be performed to evaluate for patients' symptoms and imaging parameters during exertion
• Cardiovascular magnetic resonance imaging ('Cardiac MRI')
  • Specialised scan looking specifically at the heart muscles
• Genetic testing
  • Look for the culprit gene mutation causing hypertrophic cardiomyopathy

The management goals of hypertrophic cardiomyopathy are aimed at improving patient symptoms and reducing the risks of sudden cardiac death.

Common symptoms of hypertrophic cardiomyopathy include shortness of breath and chest pain. Treatment options include:

• Medications such as beta blockers/ calcium channel blockers to reduce heart rate
• Permanent pacemaker implantation
• Radiofrequency catheter ablation to reduce thickness of heart muscles
• Open heart surgery to reduce the thickness of heart muscles ('septal myomectomy')

All patients with hypertrophic cardiomyopathy will undergo risk stratification for sudden cardiac death. Patients at high risks will be counselled for implantation of a cardiac defibrillator.

That saying, a significant proportion of local patients with hypertrophic cardiomyopathy are asymptomatic and are at low risks of sudden death. They do not require specific treatment.

Genetic Counselling

Since hypertrophic cardiomyopathy is a potentially inheritable condition, a detailed family history will be obtained. Patients will be encouraged to undergo genetic counselling and genetic testing, to identify the culprit gene. Family screening for this condition is also encouraged, in first-degree relatives.

The Cardiomyopathy Clinic at the National University Heart Centre, Singapore (NUHCS) provides a comprehensive evaluation and treatment service for patients with hypertrophic cardiomyopathy.

Panel A: Echocardiogram of a normal heart, showing normal thickness of the left ventricular (LV) walls

Panel B: Echocardiogram of a patient with hypertrophic cardiomyopathy, showing markedly thickened LV walls (red arrows)