Hypertrophic cardiomyopathy (HCM) is defined by increased left ventricular wall thickness without evidence of abnormal loading condition, such as hypertension or aortic stenosis. HCM is the most common genetic cardiac disorder that affects one of 500 of general population. Majority of patients have benign course, meanwhile some patients experience heart failure, atrial fibrillation, stroke and sudden cardiac death (SCD).
Most patients with HCM are asymptomatic and have a normal life expectancy, but some patients complained symptoms; chest pain caused by myocardial ischemia due to microvascular dysfunction and symptoms of heart failure associated with diastolic dysfunction. Atrial fibrillation is a common arrhythmia in patients with HCM and cause palpitation and syncope. SCD can be the first manifestation before diagnosis of HCM, especially in young population.
The first step of diagnosis of HCM is detection of increased left ventricular wall thickness and transthoracic echocardiography (TTE) is most commonly used for screening and diagnosis. TTE is also important in evaluation of the accompanying conditions such as systemic anterior motion of mitral valve, left ventricular outflow tract obstruction (LVOTO). Recently, cardiovascular magnetic resonance is widely used, because several studies showed that the presence of late gadolinium enhancement is useful for risk stratification of SCD in HCM patients. Genetic testing is recommended in HCM patients and their relatives.
Figure 1. Cardiovascular magnetic resonance images depicting diverse hypertrophic cardiomyopathies. (Adapted from Lancet 2013;381:242–55)
SCD is unpredictable devastating complication of HCM, thus detection of susceptible population and prevention of SCD is important. Avoidance of competitive sports is recommended, and implantable cardioverter-defibrillator is indicated in patients who experienced cardiac arrest or syncope due to ventricular arrhythmia and in those with high risk of SCD.
Beta blocker is recommended as first line therapy to improve symptoms of LVOTO. Surgical myectomy or alcohol septal ablation can be used in symptomatic patients with significant LVOTO despite maximal medical therapy. If patients have symptoms of heart failure or atrial fibrillation, standard medical treatment for respective diseases is needed.