Hypertrophic Cardiomyopathy (HCM)
What is hypertrophic cardiomyopathy?
Hypertrophic cardiomyopathy is a heart muscle disease characterised by abnormal thickening that is not sufficiently explained by another condition. It often involves the wall between the ventricles. Thickening can affect the heart's ability to relax and fill, and in some patients it obstructs blood flow out of the left ventricle.
HCM is different from the muscle thickening associated with longstanding high blood pressure or some valve diseases. Diagnosis requires assessment of the complete clinical picture.
What are the symptoms?
- Breathlessness with activity.
- Chest pain or pressure.
- Palpitations.
- Dizziness or fainting, particularly during exertion.
- Fatigue and reduced exercise tolerance.
Some patients remain symptom-free and are diagnosed through an ECG, echocardiogram or family screening.
Is HCM inherited?
Many cases are associated with genetic changes affecting heart muscle proteins and may run in families. A negative family history does not exclude HCM. Other diseases can produce a similar pattern of thickening, so a careful differential diagnosis is important.
Obstructive and nonobstructive HCM
In obstructive HCM, blood flow leaving the left ventricle is impeded by a dynamic narrowing. The obstruction may be present at rest or appear during exertion or other changes in loading conditions. Abnormal mitral valve motion and mitral regurgitation may accompany it.
Nonobstructive HCM can also cause symptoms through impaired filling, ischaemia or arrhythmias. The absence of obstruction does not eliminate the need for follow-up.
How is it diagnosed?
An ECG and echocardiogram are central to evaluation. Echocardiography assesses the distribution of thickening, ventricular function, mitral regurgitation and outflow obstruction. Provocation or exercise assessment may be needed to detect obstruction that is not apparent at rest.
Cardiac MRI helps characterise the pattern of hypertrophy and myocardial fibrosis. Holter monitoring detects arrhythmias. Genetic counselling and testing are considered according to the clinical findings and family history.
What complications can occur?
Possible complications include atrial fibrillation, heart failure symptoms, significant outflow obstruction and ventricular arrhythmias. Sudden cardiac death is a risk in a subset of patients, but not every patient with HCM has a high risk.
Risk assessment considers factors such as previous cardiac arrest or ventricular arrhythmia, unexplained fainting, family history, wall thickness, ventricular function and other imaging and rhythm findings. Risk should be reassessed over time.
How is HCM treated?
Treatment depends on symptoms, obstruction and arrhythmic risk. Beta blockers or appropriate alternative medicines may be used. Treatment of atrial fibrillation, including stroke prevention when indicated, is important.
Selected patients with persistent symptomatic obstruction may be considered for specialised drug treatment or septal reduction therapy. Surgical septal myectomy or alcohol septal ablation is evaluated according to anatomy, symptoms and experience of the treating centre.
An ICD may be recommended for patients at sufficient risk of dangerous ventricular arrhythmias. It is not required for every person with HCM.
Exercise and family screening
Exercise advice should be individualised after assessment of symptoms, obstruction and rhythm risk. A diagnosis of HCM does not mean that every form of physical activity is forbidden. Competitive or high-intensity activity requires specialist discussion.
First-degree relatives may need ECG and echocardiographic screening, and genetic assessment when appropriate.
When is urgent care needed?
Fainting during exertion, persistent chest pain, severe breathlessness or prolonged palpitations warrants prompt medical evaluation. Call 112 for an emergency.
Assoc. Prof. Sezen Bağlan Uzunget, MD — Cardiologist
This information is educational. Management requires individual specialist evaluation.
Türkçe: Hipertrofik Kardiyomiyopati