Hypertrophic Cardiomyopathy: Symptoms, Causes & Treatment

Hypertrophic cardiomyopathy (HCM) is the thickening of the heart’s ventricular muscle, which makes the heart muscle stiffer. This can make it harder for the heart to pump blood and may cause symptoms such as shortness of breath, chest pain, or heart palpitations.

The main cause of hypertrophic cardiomyopathy is genetic, and it is usually related to a family history of the condition. However, it can also develop due to high blood pressure or the body’s natural aging process.

Treatment for hypertrophic cardiomyopathy is guided by a cardiologist to help relieve symptoms, keep the condition from getting worse, and lower the risk of complications. Possible complications include atrial fibrillation, ventricular arrhythmia, and, in some cases, sudden death.

Hypertrophic cardiomyopathy symptoms

The main symptoms of hypertrophic cardiomyopathy are:

• Shortness of breath, especially during physical activity

• Chest pain, especially during physical exercise

• Excessive tiredness

• Heart palpitations

• Fast or irregular heartbeat

• Dizziness, vertigo, or feeling faint

• Swelling in the feet, ankles, or legs

In most cases, hypertrophic cardiomyopathy does not cause symptoms and may only be found during a routine heart exam.

If symptoms do occur, it is important to see a cardiologist for testing. This can help confirm the diagnosis, identify the cause, and guide the most appropriate treatment.

Confirming a diagnosis

Hypertrophic cardiomyopathy is diagnosed by a cardiologist based on symptoms, personal medical history, family history, a physical exam, and heart tests. The doctor may ask about any family history of hypertrophic cardiomyopathy, sudden death, or fainting with no clear cause, and use a stethoscope to listen for a heart murmur or abnormal heart sounds.

According to the 2024 American Heart Association and American College of Cardiology guideline, evaluation of hypertrophic cardiomyopathy can include an electrocardiogram (ECG), echocardiogram, ambulatory ECG monitoring such as a Holter monitor, exercise stress testing, and cardiac MRI in selected cases.

Possible causes

Hypertrophic cardiomyopathy is usually caused by a genetic change that leads to excessive growth of the heart muscle, making it thicker than normal. According to the American Heart Association, when HCM is genetic, each child of an affected parent has a 50% chance of inheriting it.

In addition, thickening of the heart muscle may also be related to the body’s natural aging process, uncontrolled high blood pressure, or intense long-term physical activity, as seen in some athletes.

Main types

The main types of hypertrophic cardiomyopathy are:

1. Obstructive hypertrophic cardiomyopathy

Obstructive hypertrophic cardiomyopathy is the most common type and is characterized by thickening of the wall between the left and right ventricles.

This can lead to an obstruction, making it harder for blood to pass from the left ventricle to the aorta.

2. Nonobstructive hypertrophic cardiomyopathy

Nonobstructive hypertrophic cardiomyopathy is characterized by thickening of the left ventricle, which makes it stiffer and makes it harder for the heart to pump blood to the body.

Treatment options

Treatment for hypertrophic cardiomyopathy should be guided by a cardiologist to relieve symptoms and prevent complications such as sudden death.

The main treatments for hypertrophic cardiomyopathy are:

1. Medication

Medication is usually the first treatment option for hypertrophic cardiomyopathy, as it helps lower the heart rate and reduce strain on the heart, making it easier to pump blood throughout the body.

Medications that may be used for hypertrophic cardiomyopathy include:

• Cardiac myosin inhibitors, such as mavacamten, mainly for obstructive hypertrophic cardiomyopathy
• Beta-blockers, such as metoprolol, propranolol, or atenolol
• Calcium channel blockers, such as verapamil or diltiazem
• Diuretics, such as furosemide, in some cases
• Anticoagulants, such as apixaban, rivaroxaban, dabigatran, or warfarin, when hypertrophic cardiomyopathy is associated with atrial fibrillation

These medications should only be used as prescribed by a cardiologist, based on the type of hypertrophic cardiomyopathy, symptom severity, and whether there are complications such as arrhythmias.

2. Implantable cardioverter defibrillator

An implantable cardioverter defibrillator may be recommended by a cardiologist for people with an increased risk of sudden death or for those who have had an aborted sudden death episode.

This includes people who have unexplained fainting, a left ventricular apical aneurysm, frequent or prolonged ventricular tachycardia, or a family history of sudden death.

The implantable cardioverter defibrillator is placed through surgery to detect and monitor the heart rate and rhythm. It can deliver an electric shock to the heart to correct arrhythmias and restore the heartbeat.

3. Heart surgery

Heart surgery may be recommended by a cardiologist when symptoms do not improve with other treatments.

This surgery is done by removing part of the heart muscle that separates the two ventricles, making it easier for blood to pass through and reducing strain on the heart.

4. Heart transplant

A heart transplant is one of the last treatment options and is usually recommended when medication or surgery has not been effective.