Cardiomyopathy: 5 Basic Facts About Heart Muscle Disease

Cardiomyopathy is a group of heart muscle diseases. It encompasses diverse conditions that can affect the heart’s shape or the thickness of its muscle walls. In turn, that impacts how the heart works, reducing its ability to pump blood. As the disease progresses, it can lead to arrhythmia (irregular heartbeats), heart valve problems, cardiac arrest, heart failure, and death. Symptoms, causes, and treatment depend on the type of cardiomyopathy. Here are some basic facts you should know.

1. Cardiomyopathy can affect anyone

You probably don’t associate prime athletes, children, and young adults with heart disease. However, cardiomyopathy can affect anyone, at any age and fitness level. It’s estimated that one in 500 people in the United States will have some type of cardiomyopathy. While it’s more common in older people, there are certain conditions, like arrhythmogenic right ventricular dysplasia (ARVD), that are more likely to affect teens and young adults. The prevalence is higher in males than in females, and certain types are more common in African-Americans than in Caucasians.

2. Cardiomyopathy often goes without symptoms

Many people never show any symptoms of cardiomyopathy, yet they might be at great risk of sudden cardiac death. However, for others, the disease might develop quickly with severe symptoms and complications.

Symptoms may include:

• Tiredness and fatigue (due to the lack of oxygen)
• Breathlessness with exertion or at rest (fluid builds within the lungs, making it harder to breathe)
• Swelling of the legs, ankles, and feet (due to fluid retention)
• Swelling of the abdomen and neck veins
• Palpitations (feeling your heartbeat)
• Chest pain or discomfort (most commonly after exertion or a heavy meal)
• Dizziness, light-headedness, and faintin​g

3. There are four main types of cardiomyopathy

The heart is a strong muscular pump that consists of four chambers: two on the left and two on the right. The upper chambers are called atria and they collect blood, passing it to lower chambers called ventricles. While the walls of the atria are thin and elastic, ventricles require strong, thicker walls that can contract and pump blood. Different types of cardiomyopathies affect different parts of the heart. Four types of cardiomyopathies are the most common.

• Dilated cardiomyopathy (DCM). In this condition, one of the ventricles becomes enlarged. The walls of the ventricles stretch and become thinner. That often spreads to the atria as well. The result is a weakened heart with a reduced ability to pump blood. DCM can sometimes happen in pregnancy.
• ​Hypertrophic cardiomyopathy (HCM). HCM is the most common type of inherited heart condition that happens as a result of a genetic mutation, but it can also be caused by other conditions. This type happens when the heart muscle cells enlarge and cause thickening of certain parts of the heart muscle, most commonly the walls of the left ventricle. Other parts that can thicken include the wall that separates the left and the right side of the heart, called the septum, and occasionally the mitral valve. The mitral valve is like a gate between the left atrium and the left ventricle, ensuring that blood flows in one direction. If the valve is affected, blood might leak backward. Thickening of the walls or the septum causes the inside of the left ventricle to become smaller, allowing it to hold less blood. The right ventricle can also be affected.
• Arrhythmogenic right ventricular cardiomyopathy (ARVC or arrhythmic cardiomyopathy). Heart cells are joined together by a structure called the desmosomes, made out of proteins. When there is not enough of those proteins, cells detach from each other and die. They are replaced by scar tissue and fat cells. The heart walls become thinner and the electrical conductivity is interrupted, resulting in irregular heartbeats called arrhythmia, the main symptom of this condition. As the disease progresses, the right ventricle can also be affected. Arrhythmias can be very dangerous and lead to death.
• Restrictive cardiomyopathy (RCM). This type mostly affects older adults and is less common than the other three. The ventricles become stiff and normal tissue might get replaced with scar tissue. It’s called restrictive because the heart is restricted from filling with blood. This is because the rigid walls of the affected ventricles can’t relax and expand properly.

Other types include left ventricular noncompaction and “broken heart syndrome” or Takotsubo cardiomyopathy.

4. Cardiomyopathy can be inherited or acquired

There are many possible causes of cardiomyopathy, and sometimes the cause is unknown. Some cardiomyopathies are genetic and are passed from parents to children. Because the symptoms might not occur in children, knowing your family history of cardiac disease is very important in managing the disease and preventing sudden cardiac death.

It can also be caused by some other conditions, such as:

• Viral infections
• Autoimmune disease
• Certain medications (like the ones used to treat cancer)

Certain conditions can put you at greater risk of developing acquired cardiomyopathy. These include:

• Long-term high blood pressure
• Long-term alcohol or cocaine abuse
• Endocrine diseases such as diabetes and thyroid disease
• Previous heart attack or coronary heart disease
• Pregnancy

5. Treatment and prevention include lifestyle changes