Definition

Cardiomyopathy is a heart muscle (myocardium) disease that makes it difficult for the heart to circulate blood throughout the body. Cardiomyopathy causes muscle in the heart wall to stretch, thicken, or stiffen, impairing the heart's ability to pump blood throughout the body. As the disease progresses, the heart weakens, and cardiomyopathy can lead to heart failure.

Several types of cardiomyopathy that occur most often, namely:

• Dilated cardiomyopathy is characterized by the enlargement (dilation) of the heart chambers that pump blood
• Hypertrophic cardiomyopathy is the thickening of the heart muscle
• Arrhythmogenic Right Ventricular Dysplasia (ARVD) is a heart muscle disorder that causes irregular heart rhythms
• Restrictive cardiomyopathy occurs when scarring, stiffness, or both develop in the heart muscle
• Transthyretin Amyloid Cardiomyopathy (ATTR-CM) is the accumulation of an abnormal protein (ATTR amyloidosis) in the left ventricle (the primary blood pumping chamber)

In addition, there are also several types of cardiomyopathy that do not fall into the above categories, including:

• Broken heart syndrome (takotsubo cardiomyopathy or stress-induced cardiomyopathy) is a temporary enlargement of the heart
• Chemotherapy-induced cardiomyopathy is heart damage caused by cancer treatment (chemotherapy)
• Peripartum cardiomyopathy is heart failure that develops during or after pregnancy

Causes

The cause of cardiomyopathy is often unknown (idiopathic). In other cases, the cause can be inherited or acquired:

• "Inherited" implies that you were born with cardiomyopathy due to genes inherited from your parents
• "Acquired" means that you developed cardiomyopathy due to a health condition or other type of disease during your lifetime

Certain conditions or diseases that can cause cardiomyopathy include:

• High blood pressure experienced for a long period of time
• Damage to heart tissue from a heart attack
• Rapid heartbeat experienced for a long period of time
• Heart valve disorders
• Covid-19 infection
• Certain infections, especially those that cause inflammation of the heart
• Metabolic disorders, such as obesity, thyroid disease, or diabetes
• Lack of essential vitamins or minerals in the diet, such as Thiamin (vitamin B1)
• Complications of pregnancy
• Iron build-up in the heart muscle (hemochromatosis)
• Growth of small lumps filled with inflammatory cells (granulomas) in any part of the body, including the heart and lungs (sarcoidosis)
• Abnormal protein build-up in organs (amyloidosis)
• Connective tissue disorders
• Years of excessive alcohol consumption
• Use of cocaine, amphetamines or steroids
• Use of some chemotherapy drugs and radiation therapy to treat cancer

Risk Factors

Several factors can increase the risk of cardiomyopathy, including

• Having a family history of cardiomyopathy, heart failure, and sudden cardiac arrest
• Having high blood pressure for a long period of time
• Having a condition that affects the heart, including a previous heart attack, coronary heart disease, or an infection in the heart (ischemic cardiomyopathy)
• Obesity, which makes the heart work harder
• Long-term alcohol abuse
• Use of illegal drugs, such as cocaine, amphetamines, and steroids
• Treatment with certain chemotherapy drugs and radiation therapy for cancer
• Exposure to toxic substances, such as heavy metals
• Suffering from certain diseases, such as:
• Diabetes
• Thyroid disease
• Storage of excess iron in the body (hemochromatosis)
• Amyloidosis (buildup of amyloid protein in the body)
• Sarcoidosis (growth of inflammatory body cells)
• Connective tissue disorders

Symptoms

In the early stages, cardiomyopathy may not show any signs or symptoms. But as the disease progresses, signs and symptoms usually appear, including:

• Shortness of breath on exertion or even at rest
• Swollen feet, ankles, and soles of the feet
• Abdominal bloating due to fluid accumulation
• Coughing when lying down
• Difficulty lying down or sleeping on your back 
• Fatigue
• Faster heartbeats or pounding
• Discomfort or pressure in the chest
• Dizziness, headache, and fainting

Diagnosis

To diagnose cardiomyopathy, the doctor will conduct an interview with you, asking about your symptoms, previous history of heart disease, other medical conditions, family history, and any risk factors. Next, the doctor will conduct a physical examination, particularly of your heart. The doctor may also conduct some additional supporting tests, such as:

• Blood tests can provide information about your heart's health while also ruling out other conditions
• A chest X-ray allows the doctor to see the size and structure of your heart and lungs, as well as check for fluid buildup
• Stress test to assess your heart's function during exercise
• An electrocardiogram (ECG) measures the electrical activity of your heart over a short period of time
• Holter monitors measure your heart's electrical activity over 24 or 48 hours
• An echocardiogram uses sound waves to produce real-time images of the heart and how it is beating
• Cardiac MRI captures images of your heart and coronary arteries using magnetic and radiowave technology

The doctor may also perform some diagnostic procedures to confirm the diagnosis, especially if you are planning to undergo surgery. These procedures may include:

• Cardiac catheterization. In this procedure, a long, thin wire is inserted into a blood vessel (artery or vein) leading to your heart so that the doctor can evaluate your heart for causes, including any blockages in the blood vessels
• Coronary angiography. The doctor will inject a dye into your blood vessels to view the blood flow through your arteries and heart
• Myocardial biopsy. A procedure to remove a small piece of your heart tissue so that it can be examined under a microscope

Management

Management of cardiomyopathy generally focuses on controlling the symptoms. Treatment can also slow down the progression of the disease. Some of the treatment options for cardiomyopathy are: 

• Medications: Heart medications can improve your blood flow, control symptoms, or treat the underlying condition. Doctors may prescribe blood thinners like Warfarin, beta blockers like Propranolol, or medications to lower cholesterol
• Devices to correct the heart rhythm: pacemakers or Implantable Cardioverter Defibrillators (ICDs) can treat irregular heart rhythms. These devices can monitor your heart rate and send electrical signals to your heart when irregular rhythm disturbances occur
• Devices to improve blood flow: Some devices can help your heart pump blood more efficiently. Cardiac Resynchronization Therapy (CRT) can control contractions between the left and right sides of the heart. A Left Ventricular Assist Device (LVAD) can also help your heart pump blood better
• Surgery: If you have severe symptoms or underlying heart disease, your doctor may recommend heart surgery. Doctors will usually only recommend open heart surgery or a heart transplant when all other treatments have failed to respond

Complications

Cardiomyopathy can lead to several serious complications, including:

• Heart failure
• Formation of blood clots in blood vessels
• Heart valve disorders
• Cardiac arrest and sudden death

Prevention

In most cases, there is no certain way to prevent the onset of cardiomyopathy. You can reduce your risk of cardiomyopathy and other types of heart disease by adopting a healthy lifestyle, which includes:

• Avoiding the use of alcohol or cocaine
• Controlling high blood pressure, high cholesterol and diabetes
• Consuming a healthy diet
• Exercising regularly
• Getting enough sleep
• Reducing stress

When to See a Doctor?

Consult with a doctor if you experience symptoms suggestive of cardiomyopathy. Often, cardiomyopathy is asymptomatic in its early stages.

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