Cardiomyopathy

Overview

Cardiomyopathy is a disease of the heart muscle. In cardiomyopathy, the heart muscle becomes weakened, stiffened, or abnormally thickened, making it harder for the heart to pump blood effectively. Over time, this can lead to serious complications if the condition is not properly managed.

Cardiomyopathy is not a single disease. It is a group of conditions, each affecting the heart muscle in a different way. Identifying the specific type is an important part of treatment planning, as the approach can vary considerably between types.

Cardiomyopathy can occur at any age. Some forms are inherited and run in families. Others develop as a result of high blood pressure, a viral infection, or another underlying condition. In some cases, no clear cause is found. With early diagnosis and appropriate treatment, it is often possible to slow the progression of the disease and preserve a good quality of life.

Types

There are several distinct types of cardiomyopathy, each affecting the heart muscle differently.

• Dilated cardiomyopathy. This is the most common type. The main pumping chamber of the heart, the left ventricle, becomes enlarged and its walls thin out. The heart loses its ability to contract forcefully, and blood is not pumped forward effectively. Dilated cardiomyopathy is one of the most frequent causes of heart failure.
• Hypertrophic cardiomyopathy. The heart muscle becomes abnormally thick, most often in the left ventricle and the wall between the two chambers. This thickening can obstruct the flow of blood leaving the heart. Hypertrophic cardiomyopathy is one of the leading causes of sudden cardiac arrest in young and otherwise healthy people, including athletes. It is most commonly inherited.
• Restrictive cardiomyopathy. The heart muscle becomes stiff and loses its normal flexibility. The heart continues to contract, but during the filling phase it cannot expand adequately. This prevents the chambers from filling properly with blood. Restrictive cardiomyopathy is the least common of the main types.
• Arrhythmogenic cardiomyopathy. The muscle tissue in the right ventricle is gradually replaced by fatty or fibrous tissue. This disrupts the heart's electrical system and can trigger dangerous rhythm disturbances. It is recognized as a cause of sudden cardiac arrest in young athletes and is typically inherited.
• Peripartum cardiomyopathy. This is a rare form that develops in the final months of pregnancy or shortly after delivery. The heart enlarges and its pumping function declines. It can occur in women with no prior history of heart disease. When identified early and treated promptly, heart function often improves and may recover fully.

Symptoms

The symptoms of cardiomyopathy depend on the type and severity of the condition. Some people have no symptoms for years, particularly in the early stages. As the disease progresses, symptoms may develop.

• Shortness of breath. This may begin only with exertion, such as climbing stairs or walking briskly. Over time it can occur at rest or when lying flat.
• Fatigue and weakness. When the heart cannot pump sufficient blood, a persistent sense of exhaustion is common. Everyday tasks may feel increasingly tiring.
• Swelling in the legs and ankles. Fluid can accumulate in the lower body, causing swelling in the legs, ankles, and sometimes the abdomen.
• Palpitations or irregular heartbeat. The heart may feel as though it is racing, fluttering, or beating out of rhythm. Rhythm disturbances can occur in all types of cardiomyopathy.
• Chest pain or pressure. This is particularly associated with hypertrophic cardiomyopathy and may occur during physical activity.
• Dizziness or fainting. Reduced blood flow to the brain or a serious rhythm disturbance can cause lightheadedness or loss of consciousness. Fainting during exercise should always be taken seriously.
• Cough. A persistent cough that worsens when lying flat can be related to fluid accumulating in the lungs.

When to Seek Medical Care

See a doctor if you notice any of the following.

• Shortness of breath during activity or at rest
• Unexplained and worsening fatigue
• Swelling in the legs or ankles
• Palpitations or a sensation of an irregular heartbeat
• Dizziness or feeling unsteady

Call emergency services immediately if you experience any of the following.

• Sudden, severe chest pain
• Fainting or nearly fainting, especially during exercise
• A very rapid or markedly irregular heartbeat
• Sudden, severe shortness of breath

Causes

The cause of cardiomyopathy varies by type. In some cases, more than one factor may be contributing.

• Inherited gene changes. Hypertrophic and arrhythmogenic cardiomyopathy are most often passed down through families. If one family member is affected, others may be at risk and screening is often recommended.
• High blood pressure. Persistent, uncontrolled high blood pressure forces the heart to work harder with every beat. Over time, this can cause the heart muscle to thicken or weaken.
• Coronary artery disease and heart attack. Reduced or interrupted blood supply to the heart muscle can cause damage that leads to dilated cardiomyopathy.
• Heart muscle inflammation. Viral infections can damage the heart muscle. The resulting injury can lead to weakening and enlargement of the heart chambers during recovery.
• Long-term heavy alcohol use. Sustained excessive alcohol consumption can directly weaken the heart muscle.
• Certain medications and chemotherapy. Some chemotherapy drugs can damage the heart muscle and contribute to cardiomyopathy.
• Pregnancy. The hormonal and circulatory changes of pregnancy can, in rare instances, affect the heart muscle and lead to peripartum cardiomyopathy.
• Other underlying conditions. Diabetes, thyroid disorders, iron overload, and some autoimmune diseases can affect the heart muscle and contribute to cardiomyopathy.
• Unknown causes. In some cases, a definitive cause cannot be identified despite thorough investigation.

Risk Factors

Certain factors increase the likelihood of developing cardiomyopathy.

• Family history of cardiomyopathy. Having a close relative with cardiomyopathy or a history of unexplained sudden cardiac death significantly raises the risk.
• Uncontrolled high blood pressure. High blood pressure that is poorly managed over many years places sustained strain on the heart muscle.
• Obesity. Excess weight increases the demands placed on the heart and may contribute to cardiomyopathy over time.
• Diabetes. Diabetes can affect both the coronary arteries and the heart muscle directly.
• Long-term heavy alcohol use. Chronic excessive drinking is a direct cause of one form of cardiomyopathy.
• Certain chemotherapy agents. Some drugs used to treat cancer carry a known risk of cardiac toxicity.

Diagnosis

Diagnosing cardiomyopathy involves a combination of clinical assessment, imaging, and laboratory testing. The goal is not only to confirm the presence of the disease but to determine its specific type and severity, since these directly shape treatment decisions.

• Medical history and physical examination. This is the first step in the diagnostic process. The doctor asks in detail about when symptoms began, what makes them worse, and the person's general health. A family history of cardiomyopathy, heart failure, or unexplained sudden death at a young age is specifically important and should always be mentioned. On examination, the doctor listens to the heart and lungs, assesses neck vein distension, and checks for leg swelling.
• Echocardiogram (heart ultrasound). This is the most frequently used and most informative test for cardiomyopathy. It shows the size of the heart chambers and the thickness of the heart walls. It also measures the ejection fraction, which is the percentage of blood the heart pumps out with each beat. A normal ejection fraction is above 50 percent. In dilated cardiomyopathy, the chambers are enlarged and the ejection fraction is reduced. In hypertrophic cardiomyopathy, the abnormal wall thickening is clearly visible and any obstruction to blood leaving the heart can be measured. In restrictive cardiomyopathy, abnormal filling patterns are identified. Valve function and the space around the heart are also assessed.
• Electrocardiogram (ECG). Records the heart's electrical activity and can detect rhythm disturbances, abnormal conduction patterns, and changes in the heart muscle associated with cardiomyopathy. In hypertrophic cardiomyopathy, the ECG is commonly quite abnormal and can provide a strong clue toward the diagnosis. In arrhythmogenic cardiomyopathy, characteristic changes in the right ventricular electrical signals may be seen.
• Holter monitor. A portable ECG device worn for 24 hours or longer that records the heart's rhythm continuously during normal daily activity. It captures arrhythmias that are not present during a standard ECG. It is particularly important for patients who experience palpitations or episodes of dizziness or fainting. In arrhythmogenic cardiomyopathy, it helps determine the frequency and type of ventricular rhythm disturbances.
• Cardiac MRI. This provides the most detailed images of the heart muscle available. It precisely measures chamber dimensions, wall thickness, and ejection fraction. Most importantly, a technique called late gadolinium enhancement makes areas of fibrosis, or scarring, within the heart muscle visible. This information is critical for determining the type of cardiomyopathy, assessing the extent of damage, and estimating long-term risk. Cardiac MRI is particularly valuable when echocardiography provides insufficient image quality or when distinguishing between types is difficult.
• Genetic testing and family screening. In inherited forms such as hypertrophic and arrhythmogenic cardiomyopathy, genetic testing may be recommended. A sample of blood or saliva is tested for gene changes associated with the disease. A positive result supports the diagnosis and identifies which family members should be screened. First-degree relatives, including parents, siblings, and children, are typically advised to undergo cardiac evaluation. This screening can identify the condition before symptoms develop, which may be life-saving in conditions where sudden cardiac arrest can occur without warning.
• Blood tests. Cardiac markers such as troponin indicate whether acute heart muscle damage is occurring. BNP and NT-proBNP are markers that reflect the degree of stress on the heart and help assess the severity of heart failure. Tests for thyroid function, iron levels, blood sugar, and kidney health are ordered to identify treatable underlying causes.
• Stress test. Assesses how the heart behaves during exercise by monitoring the ECG, blood pressure, and heart rate on a treadmill or exercise bike. It can reveal exercise-induced rhythm disturbances and help identify coronary artery disease as a contributing cause. In hypertrophic cardiomyopathy, it is also used to assess exercise capacity and whether the obstruction worsens during physical activity.
• Electrophysiology study. In this procedure, thin electrode catheters are passed through blood vessels in the groin into the heart. They map the heart's electrical pathways in detail. This test is used particularly in arrhythmogenic cardiomyopathy to characterize dangerous rhythm disturbances and identify their origin. In some cases, catheter ablation treatment can be performed in the same session.

Treatment

Treatment of cardiomyopathy is tailored to the type, severity, and underlying cause. The overall goals are to relieve symptoms, preserve or improve heart function, slow disease progression, and prevent serious complications, particularly sudden cardiac arrest. Most patients require a combination of approaches.

Medications for Dilated Cardiomyopathy

In dilated cardiomyopathy, medications that protect the heart and slow its deterioration form the cornerstone of treatment. Used consistently, these drugs can meaningfully improve pumping function over time.

• ACE inhibitors and ARBs. These medications widen blood vessels, reduce the workload on the heart, and slow the process of the heart enlarging further. They are among the most fundamental drugs in heart failure treatment. If ACE inhibitors cause a dry cough, an ARB can be used instead.
• ARNI (angiotensin receptor-neprilysin inhibitor). This is a newer class of medication that provides stronger protection than ACE inhibitors or ARBs alone. Clinical trials have shown it meaningfully reduces hospitalizations and death related to heart failure. It has largely replaced ACE inhibitors and ARBs as the preferred option in eligible patients.
• Beta-blockers. These slow the heart rate and reduce the force of contractions, decreasing the oxygen demand on the heart. They are started at a low dose and gradually increased. Over time, they can improve the ejection fraction.
• Aldosterone antagonists. These help regulate the balance of sodium and fluid in the body and provide additional protection against worsening heart failure, particularly in patients with more significant dysfunction.
• SGLT2 inhibitors. Originally developed as diabetes medications, these drugs were found to have a powerful beneficial effect in heart failure and have been incorporated into standard treatment. They reduce heart failure hospitalizations and cardiovascular death even in patients without diabetes.
• Diuretics. These remove excess fluid from the body and relieve breathlessness and leg swelling. They provide important symptomatic relief but do not alter the course of the underlying disease and are therefore used alongside the medications above.
• Blood thinners. An enlarged and poorly pumping heart carries an increased risk of clot formation inside the chambers. Blood-thinning medication is often necessary, particularly when atrial fibrillation is also present.

Treatment for Hypertrophic Cardiomyopathy

Treatment in hypertrophic cardiomyopathy depends on whether the thickened muscle is obstructing blood flow out of the heart and on the severity of symptoms.

• Beta-blockers. These are usually the first medication tried. By slowing the heart rate and giving the heart more time to fill between beats, they reduce both symptoms and the degree of obstruction in many patients.
• Calcium channel blockers. Verapamil is the most commonly used option in this group. It is considered when beta-blockers are not well tolerated or do not provide adequate symptom relief. It works similarly by improving the heart's filling.
• Disopyramide. This medication reduces the strength of the heart muscle's contraction, which can reduce the obstruction at the outflow tract. It is typically used in combination with a beta-blocker or verapamil rather than alone.
• Mavacamten. This is a newer targeted medication that directly reduces the excessive force of the heart muscle's contraction by acting on the molecular level. Clinical trials have shown it can significantly reduce obstruction and improve symptoms. It is an option for patients whose symptoms are not adequately controlled with older medications.
• Septal myectomy. This is an open-heart operation performed in patients whose symptoms are severe and who have not responded sufficiently to medications. The surgeon removes a small portion of the thickened wall between the two ventricles from inside the heart. This widens the outflow channel and eliminates or substantially reduces the obstruction. In experienced centers, septal myectomy offers excellent and durable long-term results and is considered the gold standard intervention for obstructive hypertrophic cardiomyopathy.
• Alcohol septal ablation. This is a catheter-based alternative for patients who are not suitable for surgery or who prefer a less invasive approach. A thin catheter is passed through a blood vessel in the groin to the heart. Through this catheter, a small amount of pure alcohol is carefully injected into the tiny artery that supplies the thickened portion of the septal wall. The alcohol causes a controlled, localized area of the muscle to weaken, which reduces the obstruction. The procedure is less invasive than surgery but is not appropriate for all patients, and the decision between the two approaches requires careful assessment at a specialist center.

Treatment of Rhythm Disturbances

Rhythm disturbances can occur in all forms of cardiomyopathy. The treatment approach depends on the type and severity of the arrhythmia.

• Antiarrhythmic medications. These drugs work by regulating the electrical signals in the heart to suppress or reduce the frequency of abnormal rhythms. Amiodarone and sotalol are among the most commonly used. The choice of medication depends on the type of arrhythmia and the form of cardiomyopathy, as some antiarrhythmic drugs must be used with caution in certain types.
• Catheter ablation. In this procedure, thin catheters are passed through blood vessels in the groin into the heart. The electrical pathways are mapped in detail to identify the precise origin of the abnormal rhythm. Once located, radiofrequency energy is delivered through the catheter tip to selectively destroy the small area of tissue responsible. The procedure is performed under local anesthesia and sedation. Catheter ablation is effective for rhythm disturbances that do not respond adequately to medication or that recur frequently. In cardiomyopathy, because the heart muscle changes are often widespread, the procedure may need to be repeated in some patients.
• Implantable cardioverter-defibrillator (ICD). This is a small device implanted under the skin of the chest, connected to the heart by thin wires. It continuously monitors the heart rhythm. If it detects a life-threatening rhythm such as ventricular fibrillation or ventricular tachycardia, it delivers an electrical shock to restore a normal rhythm. An ICD is highly effective at preventing sudden cardiac death in high-risk patients with cardiomyopathy. Once implanted, it remains in place permanently and the battery is replaced when needed, typically after several years.
• Cardiac resynchronization therapy (CRT). In advanced dilated cardiomyopathy, the right and left ventricles sometimes beat in an uncoordinated way, reducing pumping efficiency. A CRT device uses multiple electrodes to stimulate both ventricles simultaneously, restoring coordination. This can improve the ejection fraction and significantly relieve symptoms. CRT devices are often combined with an ICD function in a single device, providing both resynchronization and protection against dangerous arrhythmias.

Advanced Treatments

• Mechanical circulatory support. In patients whose heart function has deteriorated severely despite all medical and device therapies, a left ventricular assist device (LVAD) may be considered. This is a mechanical pump implanted alongside or inside the heart that takes over the work of the left ventricle, moving blood forward to the body. An LVAD can be used as a bridge to transplantation while a suitable donor heart is awaited, or as a long-term treatment in patients who are not transplant candidates.
• Heart transplantation. In end-stage cardiomyopathy that does not respond to any other treatment, heart transplantation may be considered. The waiting time for a donor heart varies significantly from patient to patient. After transplantation, lifelong immunosuppressive medications are required to prevent the body from rejecting the new heart.

Complications

When cardiomyopathy is not adequately treated or controlled, serious complications can develop over time.

• Heart failure. This is the most common long-term complication, particularly in dilated cardiomyopathy. As the heart continues to weaken, it may gradually lose its ability to meet the body's needs.
• Dangerous heart rhythm disturbances. All types of cardiomyopathy can disrupt the heart's electrical system, leading to palpitations, fainting, and in some cases sudden cardiac arrest.
• Sudden cardiac arrest. The risk is particularly elevated in hypertrophic and arrhythmogenic cardiomyopathy, especially in young and physically active people. In untreated or unrecognized cases, sudden cardiac arrest can be the first sign of the disease.
• Heart valve problems. As the heart enlarges, valves may no longer close properly, causing blood to leak backward and placing further strain on the heart.
• Blood clots and stroke. Blood clot formation is more likely in an enlarged or poorly pumping heart. If a clot travels to the brain, it can cause a stroke.

Lifestyle

Cardiomyopathy is a long-term condition. Lifestyle choices can meaningfully support medical treatment, slow disease progression, and reduce the risk of complications.

Physical Activity

Exercise recommendations in cardiomyopathy depend on the type and severity of the condition and must be individualized.

In dilated cardiomyopathy, regular moderate activity is often encouraged and can support recovery of heart function. High-intensity or competitive sport may need to be avoided. In hypertrophic and arrhythmogenic cardiomyopathy, vigorous exercise and competitive sport are generally not recommended because they can increase the risk of dangerous rhythm disturbances and sudden cardiac arrest. The decision about what is safe for you should be made by your cardiologist, not based on how well you feel.

Salt and Fluid Intake

Reducing salt intake helps prevent fluid from accumulating in the body, which reduces the strain on the heart. Processed foods, canned goods, and ready-made meals are often high in sodium and are worth limiting. Ask your doctor for a specific daily target that fits your situation. In some cases, total fluid intake may also need to be monitored.

Daily Weight Monitoring

Weighing yourself at the same time each morning and keeping a record is a practical way to detect fluid buildup before symptoms worsen. A gain of several pounds over a short period can indicate that fluid is accumulating. Contact your doctor if this happens, and ask your care team at what point a weight change should prompt you to call or seek care.

Medications

Treatment of cardiomyopathy typically requires long-term, consistent medication use. Stopping medications without medical guidance, even when you feel well, can lead to rapid deterioration. If a side effect is troubling you, speak with your doctor rather than discontinuing the medication on your own. Always inform any other treating physician about your cardiac medications before a new drug is started.

Smoking and Alcohol

Smoking damages blood vessels and the heart muscle, and stopping is one of the most beneficial steps a person with cardiomyopathy can take. Effective support is available through your doctor or pharmacist.

Alcohol is a direct cause of one form of cardiomyopathy and can worsen others. Stopping or significantly reducing alcohol consumption can allow meaningful improvement in heart function in some people. Talk with your doctor about what is appropriate for your specific situation.

Informing Family Members

In inherited forms of cardiomyopathy such as hypertrophic and arrhythmogenic types, first-degree relatives, including children, are often recommended to undergo cardiac evaluation. Early detection in family members can be life-saving, since these conditions can cause sudden cardiac arrest without prior warning. Discuss this with your cardiologist.

Regular Follow-up

Cardiomyopathy requires ongoing monitoring. Repeat echocardiograms, ECGs, and blood tests are used to track changes in heart structure and function over time. Do not miss follow-up appointments. Contact your doctor promptly or seek emergency care if any of the following develop.

• Shortness of breath that returns or worsens
• Swelling in the legs or ankles that is new or increasing
• Chest pain or pressure
• A very fast, slow, or irregular heartbeat
• Fainting or nearly fainting, especially during activity
• A gain of several pounds over a short period

Preparing for Your Appointment

Coming prepared to an appointment for cardiomyopathy helps your doctor make a more accurate assessment and choose the most appropriate treatment for you.

What You Can Do

• Write down when symptoms began and how they have changed over time.
• Mention any family history of cardiomyopathy, heart failure, or unexplained sudden cardiac death, including in young relatives.
• List all medications, supplements, and herbal products you are currently taking.
• Be honest about your alcohol and smoking habits.
• Bring any home blood pressure or weight readings you have recorded.
• Write your questions down before the appointment.

Questions You May Wish to Ask Your Doctor

• Which type of cardiomyopathy do I have and what does that mean for me?
• Is this condition inherited and should my family members be screened?
• Which medications do I need and for how long?
• What type and amount of exercise is safe for me?
• Do I need an implantable device to protect against sudden cardiac arrest?
• What steps will help prevent the condition from worsening?
• Which symptoms should prompt me to seek emergency care?
• How often do I need follow-up appointments?

Questions Your Doctor May Ask You

• When did your symptoms begin and how have they progressed?
• Is there a family history of cardiomyopathy or sudden cardiac death at a young age?
• Do you have high blood pressure, diabetes, or a thyroid condition?
• How much alcohol do you drink and for how long?
• Have you received chemotherapy in the past?
• Have you experienced chest pain, shortness of breath, or fainting during exercise?
• What medications are you currently taking?