Definition

Hypertrophic cardiomyopathy (HCM) is a form of cardiomyopathy. This is a condition in which the heart muscle thickens due to genetic problems with the muscle’s structure. As the muscle thickens, it must work harder to pump blood, which strains the heart muscle. Sometimes, the thickened muscle gets in the way of the blood leaving the heart and causes a blockage. This blockage can cause the nearby heart valve, called the mitral valve, to become leaky. HCM can cause uneven muscle growth which can cause the heart to pump in a disorganized way. Rarely, it can cause abnormal heart rhythms that can even be fatal.

There are two types of hypertrophic cardiomyopathy:

  • Hypertrophic obstructive cardiomyopathy (HOCM)—the muscle between the two valves of the heart becomes so enlarged that it obstructs the blood flow in the heart
  • Non-obstructive hypertrophic cardiomyopathy—non-obstructive form, the enlarged muscle is not large enough to block blood flow
Normal Heart and Heart with Hypertrophic Cardiomyopathy
Hypertrophic Cardiomyopathy
Copyright © Nucleus Medical Media, Inc.

Causes

Causes of HCM include:

  • A gene that causes the abnormal structure of the heart muscle. It can be inherited or can happen from changes in the genes over time.
  • A defective gene that controls growth of the heart muscle
  • Infection

In people over age 60, HCM is likely to be caused by or related to high blood pressure.

Risk Factors

HCM is usually most severe when it occurs in yournger people, but it can occur at any age.

Other factors that may increase your chances of HCM include:

  • Having a family member with HCM
  • Being over age 60 and having hypertension

Symptoms

Symptoms include:

  • Chest pain
  • Fainting, particularly during exercise
  • Lightheadedness, particularly following exercise
  • Rapid heartbeat
  • Shortness of breath or difficulty breathing
  • General fatigue
  • Tiring easily during exercise or activity
  • Shortness of breath when lying down

These symptoms can be caused by some of the side effects of the condition, including heart arrhythmias. The blocked or reduced blood flow is usually the cause of symptoms like lightheadedness, fainting, and difficulty breathing.

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done.

Your bodily fluids may be tested. This can be done with blood tests.

Your body's response to exercise may be tested. This can be done with a stress test.

Images may be taken of your bodily structures. This can be done with:

Your heart activity may be monitored. This can be done with a portable ECG.

The diagnosis is only made in people who do not have other causes of cardiomyopathy such as amyloidosis, sarcoidosis, coronary or valvular heart disease.

Treatment

Many individuals with HCM live a normal, healthy life with few symptoms. However, HCM does increase the risk of sudden death.

Treatment focuses on controlling symptoms and preventing complications. Talk with your doctor about the best treatment plan for you. Treatment may include:

Medications

Medications may be used to help maintain proper and regular heart function. These may include:

  • Beta-blockers and calcium channel blockers
  • Anti-arrhythmics
  • Blood thinners

Surgery

The thickened portion of the heart muscle is cut and removed. This may be needed if you have severely blocked blood flow from the heart.

If the mitral valve is leaking, surgery may also be done to repair or replace the mitral valve.

Alcohol Septal Ablation

Alcohol is injected into the arteries of the thickened portion of the heart. This helps to reduce the blockage in the heart and improve blood flow out of the heart.

Implantable Cardioverter Defibrillators (ICD)

This ICD is implanted if you are at increased risk for sudden death.

Prevention

To help reduce your chances of HCM:

  • Talk to your doctor about screening tests if you have a family history.
  • Follow your treatment plan to manage chronic heart or other medical conditions.

Revision Information