Cardiomyopathy – Types, Causes and Prevention

Definition

Cardiomyopathy is a general term that refers to diseases of the heart muscle. In cardiomyopathy, the heart muscle becomes enlarged, thick or tough, and cannot beat as well as it should. The heart is less able to pump blood effectively and prone to heart failure, heart valve problems, and to arrhythmias, including atrial fibrillation (Afib or AF). People with Afib are five times more likely to have a stroke than those who do not have Afib. This is why stroke prevention is often an important consideration for people with cardiomyopathies.

Cardiomyopathy can affect people of all ages, even children. Continue reading to learn more about the different types of cardiomyopathy. While cardiomyopathy is a serious condition, it is usually treatable. Treatment options include medication, surgery, implantable devices and minimally invasive procedures. The type of treatment your doctor recommends will depend on the type of cardiomyopathy and the extent of the problem.

Types of Cardiomyopathy

There are four types of cardiomyopathy. Treatment depends on the type you have and how serious it is.

Dilated (congestive) cardiomyopathy

This is the most common form of cardiomyopathy. It often occurs as a result of restricted blood flow to the heart muscles (cardiac ischemia). It weakens and thins the walls of the heart chambers. The disease often starts in the left ventricle, which is the main pumping chamber of the heart. When the walls dilate and become thin, the inside of the chamber gets larger. The left ventricle beats with less force, so it pumps blood less effectively to the rest of your body. The problem can then spread to the heart’s right ventricle and the atria.

Dilated cardiomyopathy mostly affects middle-aged men. Causes include viral infection of the heart muscle, excessive alcohol consumption, cocaine and the abuse of antidepressant drugs. In rare cases it may be caused by pregnancy or connective tissue disorders such as rheumatoid arthritis. In most cases of dilated cardiomyopathy, the cause is unknown.

Hypertrophic cardiomyopathy (HCM)

HCM occurs because the heart’s walls become thickened, which makes it harder for the heart to pump blood. In obstructive hypertrophic cardiomyopathy the ventricle size remains normal, but thickening of the walls may block blood flow out of the ventricles. Sometimes the wall between the bottom chambers of the heart (the septum) also becomes enlarged and blocks blood flow out of the left ventricle.

HCM can lead to the development of abnormal heart rhythms (arrhythmias). In rare cases, some people with HCM may experience a cardiac arrest  (also known as cardiopulmonary arrest) during vigorous physical activity. HCM is usually an inherited disease caused by gene mutations, but sometimes the cause isn’t clear. Although it can develop at any age, HCM is usually more severe if diagnosed during childhood.

Restrictive cardiomyopathy

In this type of cardiomyopathy, the heart muscle becomes less elastic which prevents the heart from stretching properly. This limits the amount of blood that can fill the heart’s chambers.

Restricted cardiomyopathy is a rare type of cardiomyopathy that affects older people most often. It can be caused by other diseases such as hemochromatosis, amyloidosis, sarcoidosis, connective tissue disorders or eosinophilic heart disease.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) or Arrhythmogenic right ventricular dysplasia (ARVD)

ARVC/D is a rare type of cardiomyopathy. The right ventricular muscle is replaced by fat or scar tissue, which interferes with the normal heartbeat rhythm.

ARVC/D is a leading cause of sudden cardiac death among young people – particularly young athletes – but it can be present in people at any age and fitness level. ARVC/D is often caused by genetic mutations.

The most common symptoms of ARVC/D include palpitations, fainting, chest pain and a rapid, irregular heartbeat. Consult a doctor if you experience any of these symptoms, especially if someone in your immediate family has been diagnosed with ARVC/D.

Causes of Cardiomyopathy

Some people get cardiomyopathy due to another condition or risk factor they have, but for many the cause can’t be found.

Some things that can lead to cardiomyopathy include:

• High blood pressure
• Damage from a heart attack
• Abnormal heart rhythms
• Heart valve disease
• Endocarditis
• Too much iron in your heart (hemochromatosis)
• Amyloidosis (when too much abnormal protein builds up in your organs)
• Drinking too much alcohol

Cardiomyopathy Symptoms

Some people with cardiomyopathy don’t have any symptoms. Others only notice signs when the condition gets worse.

Cardiomyopathy symptoms get worse over time. If heart failure develops, these can include:

• Feeling very tired after normal activity
• Inability to lie flat (orthopnea)
• A fast heart rate
• Shortness of breath, breathing fast, or trouble breathing
• Chest pain
• Swelling in the legs, ankles, and feet
• Belly bloating
• In infants, trouble feeding and poor weight gain (failure to thrive)

Other symptoms can include heart palpitations; and dizziness, light-headedness, or fainting.

Risk factor

Cardiomyopathy risk factors some of which you can’t change include:

• History of heart failure, cardiomyopathy or sudden cardiac arrest in your family.
• Personal history of heart attacks.
• Long-term use of cocaine or alcohol.
• Pregnancy.
• A highly stressful experience, such as the loss of a loved one.
• Radiation or chemotherapy to treat cancer.
• A body mass index (BMI) higher than 30.

Complications

Cardiomyopathy can lead to serious complications, including:

• Heart failure: The heart can’t pump enough blood to meet the body’s needs. Untreated, heart failure can be life-threatening.
• Blood clots: Because the heart can’t pump effectively, blood clots might form in the heart. If clots enter the bloodstream, they can block the blood flow to other organs, including the heart and brain.
• Heart valve problems: Because cardiomyopathy causes the heart to enlarge, the heart valves might not close properly. This can cause blood to flow backward in the valve.
• Cardiac arrest and sudden death: Cardiomyopathy can trigger irregular heart rhythms that cause fainting or, in some cases, sudden death if the heart stops beating effectively.

Diagnosis

If cardiomyopathy is suspected, our heart specialists will take a thorough history and perform a physical exam. Other diagnostic tests may be ordered, including one or more of the following.

Electrocardiogram (ECG)

Small electrodes are placed on your skin to record your heart’s electrical impulses and rhythms.

Holter Monitor

A battery-operated, portable, and wearable heart monitor records your heart’s electrical signal for days or weeks to identify abnormal heart rhythms.

Stress Test

Also known as a cardiopulmonary exercise or CPX test, a stress test is an ECG that’s performed while you exercise on a treadmill or stationary bike. This test helps identify causes of breathlessness, measure a person’s exercise capacity, and determine why exercise capacity may be reduced.

Echocardiogram

An ultrasound probe is moved over the surface of your chest to capture moving images of your heart using sound waves. This allows doctors to determine your heart’s chamber dimensions, wall thickness, shape, valve structures, and overall strength.

Stress Echocardiogram

A stress echocardiogram is performed while you walk on a treadmill or ride a stationary bike, or when a chemical is used to stimulate the heart. Like a traditional stress test, a stress echo helps identify changes in your heart’s function during exertion. In people with hypertrophic cardiomyopathy, this test may help determine whether outflow obstruction during exercise could be causing symptoms.

Transesophogeal Echocardiogram (TEE)

A thin ultrasound probe is put down your throat and into your esophagus. It uses sound waves to create highly detailed, 3D images of your heart. This test can show the inside of the heart and its valves more clearly that a traditional echocardiogram.

Cardiac Catheterization

A thin, long, hollow tube is inserted into a large blood vessel and guided through your circulatory system to your heart. A heart catheterization helps measure pressures in the heart and lungs and look for any blockages in the coronary arteries, which supply the heart with oxygen. Contrast dye is sometimes injected so that blood vessels (and any blockages or narrowed areas) appear on X-rays.

CT Coronary Angiography

A contrast agent is injected into a vein in your arm and then a CT scan produces highly detailed 3D images of your coronary arteries to help identify anatomy and blockages. This test can also be helpful to look at other blood vessels in the heart, lungs, and heart valves.

Cardiac MRI

Radio waves, magnets, and a computer create still and moving images of your overall heart structure, heart muscle function, blood flow, and surrounding structures. This test can check for scarring inside the heart muscle walls.

Nuclear Cardiac Testing

Radioactive dye is used during imaging to create pictures of blood flow through your heart. This test may be done while at rest or with exercise. It helps to evaluate overall heart function and blood flow to the heart muscle.

Treatment and medications for cardiomyopathy

Treatment of cardiomyopathy is based on its cause. While some people can get better with medications, others might have to undergo surgery.

Medications

These are several medications that help reduce the symptoms of cardiomyopathy and also help avoid further complications. It is recommended to consult your doctor regarding the medicines best suited for you, as medicines are prescribed taking into consideration the type of cardiomyopathy, the severity of the symptoms and also the underlying conditions. It is important to take your medicines on time and follow the instructions and dosage as prescribed by the doctor.

There are several different types of medications for cardiomyopathy, depending on which type the patient has and the symptoms.

• Angiotestin converting enzyme (ACE) inhibitors are drugs that dilate blood vessels in the body, fighting the constricting effect caused by heart failure.
• Antiarrhythmic medications combat the abnormal heart rhythms caused by irregular electrical activity within the heart.
• Beta blockers block certain chemicals from binding to nerve receptors in the heart, slowing the heart rate and lowering blood pressure.
• Blood thinners or anticoagulants help prevent the formation of blood clots, especially in children with the dilated form of cardiomyopathy.
• Diuretics prevent the build-up of fluid in the body and can help breathing by reducing fluid in the lungs. These drugs may also be helpful in treating scar tissue on the heart.

Surgeries/Medical procedures

Implantable cardioverter-defibrillator – This device is implanted in the heart to monitor its rhythm and detect abnormal beating. It delivers electric shocks when the irregular rhythms of your heart need to be controlled. An ICD cannot cure cardiomyopathy. But it can help monitor and manage serious complications of cardiomyopathy.

Pacemakers – Pacemakers are small devices that are placed under the chest or abdomen skin. It causes electrical impulses that control arrhythmias. Arrhythmia refers to the irregular beating of the heart.

Ventricular assist device – This device helps in normalizing blood flow through the heart. It is implanted only when other non-invasive methods of treatment remain unsuccessful for treatment of cardiomyopathy. Sometimes it is a long-term treatment option and other times, the device is used till a heart transplant is done.

Heart Transplant – A heart transplant is done when an individual is diagnosed with end-stage heart failure. It is done after trying out medications and other methods of treatment for cardiomyopathy.

Septal Myectomy – It is a form of open-heart surgery in which a portion of the thick muscle wall in the heart is removed. The removal of the thickened heart muscles helps in improving the flow of blood through the heart. It is also good for managing mitral valve regurgitation. Mitral valve regurgitation is a type of condition with the mitral valve – the value between the left atrium and left ventricle doesn’t close properly, thus allowing blood to flow backwards into the heart. This surgical method is used for hypertrophic cardiomyopathy treatment in particular.

Therapies

Septal ablation – In this non-surgical method, a small portion of the thick heart muscle is destroyed by injecting alcohol with the help of a catheter into the artery responsible for supplying blood to the septum. This enables proper blood flow through the area.

Radiofrequency ablation – This method requires the guidance of long and flexible catheters to the heart through blood vessels. A small spot of abnormal heart tissue leading to irregular heart rhythms is destroyed by the catheter. The electrodes present at the tip of the catheter provide the energy to damage the heart tissue.

How to prevent cardiomyopathy?

If cardiomyopathy runs in your family, you may not be able to completely prevent it. But, you can take steps to keep your heart healthy and minimize the impact of this condition.

Even if cardiomyopathy isn’t part of your family history, it’s still important to take steps to make sure you don’t develop a heart condition or disease that could put you at an increased risk of cardiomyopathy.

The steps you can take to help lower your risk of cardiomyopathy include:

• Getting regular exercise. Try to limit how much you sit each day, and focus on getting at least 30 minutes of exercise most days of the week.
• Getting enough sleep. Sleep deprivation is linked to an increased risk of heart disease. Try to get at least 7 to 8 hours of sleep each night.
• Eating a heart-healthy diet. Try to limit your intake of sugary, fried, fatty, and processed foods. Focus instead on fruits, vegetables, whole grains, lean proteins, nuts, seeds, and low fat dairy. Also limit your intake of salt (sodium), which can raise your risk of high blood pressure.
• Reducing your stress levels. Try to find healthy ways to lower your stress when possible. You may want to consider taking regular brisk walks, doing deep breathing exercises, meditating, doing yoga, listening to music, or talking with a trusted friend.
• Quitting smoking, if you smoke. Smoking can negatively affect your entire cardiovascular system, including your heart, blood, and blood vessels.
• Managing underlying health conditions. Work closely with your doctor to control and manage any underlying health conditions that may raise your risk of cardiomyopathy.