Cardiomyopathy: Types, Causes, and Treatment

The word cardiomyopathy literally means “heart muscle disease,” and it is more common than most people realize — hypertrophic cardiomyopathy alone affects an estimated 1 in 500 people, according to the American Heart Association. Cardiomyopathy encompasses a group of diseases in which the heart muscle becomes structurally and functionally abnormal — thickened, stretched, stiffened, or replaced by scar tissue — impairing its ability to pump blood effectively. Some forms progress silently for years before symptoms appear, while others present suddenly with life-threatening arrhythmias. Understanding the different types and their management is essential for anyone living with or at risk for this condition. For an overview of related conditions, visit our medical conditions guide. This guide is educational only and is not a substitute for care from a qualified cardiologist.

What Happens in Cardiomyopathy

In a healthy heart, the muscular walls of the ventricles contract and relax in a coordinated rhythm, efficiently pumping blood to the lungs and body. In cardiomyopathy, the heart muscle itself is diseased. Depending on the type, the walls may become too thick, too thin, too stiff, or infiltrated with abnormal substances. The result is impaired pumping function, reduced cardiac output, and eventually heart failure.

Cardiomyopathy can also disrupt the heart’s electrical system, predisposing to dangerous arrhythmias including ventricular tachycardia and ventricular fibrillation — which can cause sudden cardiac death. In fact, cardiomyopathy is one of the leading causes of sudden cardiac arrest in young athletes and seemingly healthy adults, which is why warning signs like fainting during exercise are never brushed off. The CDC identifies cardiomyopathy as a major contributor to heart failure and cardiac transplantation in the United States.

Cardiomyopathies are broadly classified as primary (the heart muscle is the primary site of disease) or secondary (the heart is damaged as a consequence of a systemic condition). They are further categorized into structural and functional types — dilated, hypertrophic, restrictive, arrhythmogenic, and the stress-induced takotsubo pattern — each with distinct characteristics, causes, and treatment approaches.

Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is the most common form, accounting for a large share of all cardiomyopathies. In DCM, the left ventricle — the heart’s main pumping chamber — becomes enlarged (dilated) and weakened, reducing its ability to contract effectively. The ejection fraction, which normally ranges from about 55 to 70 percent, drops below 40 percent and often much lower in severe cases.

The causes of DCM are diverse. A substantial proportion of cases — on the order of a third to a half in various series — have a genetic basis, with mutations identified in genes encoding structural proteins of the heart muscle such as titin, lamin A/C, and desmin. Acquired causes include viral myocarditis (inflammation from infections such as Coxsackievirus, adenovirus, or SARS-CoV-2), chronic heavy alcohol use (“alcoholic cardiomyopathy”), cocaine and other stimulant use, certain chemotherapy drugs (particularly anthracyclines like doxorubicin), thyroid disease, and peripartum cardiomyopathy (occurring late in pregnancy or in the months after delivery).

In many cases, no specific cause is identified, and the condition is labeled “idiopathic.” According to research published in JACC (Journal of the American College of Cardiology), genetic testing is increasingly revealing underlying mutations in patients previously thought to have idiopathic DCM, which has important implications for family screening.

Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is characterized by abnormal thickening (hypertrophy) of the heart muscle, most commonly affecting the wall between the two ventricles (the interventricular septum). HCM is the most common inherited heart disease, affecting roughly 1 in 500 people, and is caused by mutations in genes encoding sarcomeric proteins — the contractile machinery of the heart. Many mutations across several genes have been identified, most commonly involving beta-myosin heavy chain and myosin-binding protein C.

HCM is usually inherited in an autosomal dominant pattern, meaning each child of an affected parent has about a 50 percent chance of inheriting the mutation. However, the expression is highly variable — some family members with the mutation may have severe thickening and symptoms, while others may have minimal or no apparent disease.

In roughly two-thirds of HCM patients, the thickened septum obstructs blood flow out of the left ventricle during contraction — a condition known as hypertrophic obstructive cardiomyopathy (HOCM). This obstruction increases the heart’s workload and can cause exertional chest pain, shortness of breath, dizziness, and fainting. HCM is a leading cause of sudden cardiac death in young athletes, though the absolute risk for any individual patient is relatively low. This is why fainting or near-fainting during exertion, a family history of sudden death, or unexplained palpitations always warrant prompt cardiology evaluation. The Mayo Clinic emphasizes that risk stratification and appropriate management — including implantable defibrillators for higher-risk patients — have made sudden-death prevention far more effective than in the past. Decisions about sports participation in HCM are individualized and made together with a cardiologist.

Restrictive and Arrhythmogenic Cardiomyopathy

Restrictive Cardiomyopathy

Restrictive cardiomyopathy (RCM) is the least common type. The ventricles become stiff and rigid, impairing their ability to relax and fill with blood between beats (diastolic dysfunction), even though the squeezing (contractile) function may be preserved. Causes include amyloidosis (the most common identified cause, in which abnormal proteins infiltrate the heart muscle), sarcoidosis, hemochromatosis (iron overload), radiation therapy, and idiopathic fibrosis. Cardiac amyloidosis, once considered rare, is increasingly recognized — particularly transthyretin amyloidosis (ATTR), which is now understood to affect a meaningful share of older adults with heart failure and preserved ejection fraction. Better imaging and awareness have made it far more diagnosable, and, importantly, it is now treatable (see the treatment section).

Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC), sometimes called arrhythmogenic cardiomyopathy, involves progressive replacement of heart muscle — classically the right ventricle — with fibrous and fatty tissue. This disrupts normal electrical conduction and creates a substrate for dangerous ventricular arrhythmias. ARVC is usually genetic, with mutations in desmosomal proteins, and is a significant cause of sudden cardiac death in young people and athletes; intense endurance exercise can accelerate it in susceptible individuals. Diagnosis can be challenging and typically combines cardiac MRI, ECG findings, family history, and genetic testing.

Takotsubo (Stress) Cardiomyopathy

Takotsubo cardiomyopathy, also called stress cardiomyopathy or “broken heart syndrome,” is a usually temporary weakening of the heart muscle triggered by intense emotional or physical stress. It most often affects women after menopause and can mimic a heart attack, with chest pain and shortness of breath and changes on the ECG and blood tests — which is one reason anyone with these symptoms needs emergency evaluation rather than assuming it is “just stress.” Most people recover heart function within days to weeks, but the acute episode can be serious and occasionally life-threatening, so it is managed in the hospital.

Symptoms Across All Types

The symptoms of cardiomyopathy overlap significantly across types, as they largely reflect the heart’s inability to pump blood efficiently. Shortness of breath — initially with exertion and eventually at rest or when lying flat — is the most common complaint. Fatigue, reduced exercise tolerance, and swelling of the legs, ankles, or abdomen (edema) are hallmarks of heart failure, which is the eventual outcome of many cardiomyopathies if untreated. Rapid weight gain over a few days usually reflects fluid retention and should prompt a call to your care team.

Palpitations, dizziness, and fainting (syncope) may indicate arrhythmias and warrant immediate evaluation — fainting during exertion is especially concerning. Chest pain can occur with HCM (from obstruction or reduced blood supply to the thickened muscle) and occasionally with other types. In some patients, the first sign of cardiomyopathy is a cardiac arrest or a blood clot — poorly contracting chambers are prone to forming clots (thrombi) that can cause stroke or block an artery elsewhere.

When to seek emergency care: Call 911 or go to the nearest emergency room for severe shortness of breath (especially at rest or lying flat), chest pain, fainting or near-fainting, palpitations with lightheadedness, or rapid weight gain from fluid. See the red box at the top of this page for the full list.

Diagnosis

Echocardiography (a heart ultrasound) is the first-line diagnostic tool, revealing chamber size, wall thickness, contractile function, and valve abnormalities characteristic of each cardiomyopathy type. Cardiac MRI provides more detailed tissue characterization and can detect scarring (fibrosis), fatty infiltration (in ARVC), and amyloid infiltration. According to the American College of Cardiology, cardiac MRI has become an essential part of the diagnostic workup of cardiomyopathy.

An electrocardiogram (ECG) often shows characteristic abnormalities, and Holter monitors or implantable loop recorders detect intermittent arrhythmias. Blood tests may include BNP or NT-proBNP (markers of heart failure), troponin, thyroid function, iron studies, and tests to screen for amyloidosis. For suspected cardiac ATTR amyloidosis, a specific nuclear bone-tracer scan (PYP/DPD scan) can often confirm the diagnosis without a biopsy.

Genetic testing and counseling are increasingly important, particularly for HCM, DCM with a family history, and ARVC. Identifying a causative mutation allows “cascade screening” of at-risk family members. Endomyocardial biopsy — taking a small sample of heart tissue — may occasionally be needed to confirm infiltrative diseases like amyloidosis or sarcoidosis when noninvasive testing is inconclusive.

Treatment Strategies

Treatment of cardiomyopathy depends on the specific type, severity, and underlying cause, and it is always directed by a cardiologist. The medications below are described in general terms only — doses are individualized by your prescriber, and you should never start, stop, or change a heart medication on your own, even if you feel well.

For DCM with reduced ejection fraction, guideline-directed medical therapy (GDMT) for heart failure is the foundation. This generally includes an ACE inhibitor, ARB, or the combination sacubitril/valsartan; a beta-blocker; a mineralocorticoid receptor antagonist (such as spironolactone or eplerenone); and an SGLT2 inhibitor. These four pillars have been shown across numerous clinical trials to improve survival and reduce hospitalizations in heart failure with reduced ejection fraction.

For HCM, treatment focuses on relieving symptoms and preventing sudden death. Beta-blockers and certain calcium channel blockers (verapamil or diltiazem) are traditional first-line options for obstruction-related symptoms. A newer class, the cardiac myosin inhibitors, directly targets the excessive contraction that drives obstruction: mavacamten (Camzyos) was approved in 2022, and a second agent, aficamten (Myqorzo), was approved by the FDA in December 2025 — both for symptomatic obstructive HCM and both requiring careful monitoring under specialist supervision. For patients with severe, refractory obstruction, septal reduction therapy (surgical myectomy or alcohol septal ablation at experienced centers) can provide dramatic relief.

For restrictive cardiomyopathy, treatment targets the underlying cause when possible. Cardiac ATTR amyloidosis — once considered untreatable — now has disease-modifying options: the transthyretin stabilizer tafamidis reduces death and hospitalization, and acoramidis (Attruby), another TTR stabilizer, was FDA-approved in November 2024 for ATTR cardiomyopathy. Additional gene-silencing therapies for ATTR are advancing as well; your cardiologist can advise which options apply to your specific diagnosis. Heart-failure medications are used cautiously in restrictive physiology, as these patients may not tolerate aggressive diuresis or blood-pressure lowering.

Implantable cardioverter-defibrillators (ICDs) are recommended for patients at high risk of sudden cardiac death, including those with severely reduced ejection fraction despite GDMT, certain higher-risk HCM patients, and ARVC patients with risk factors. Cardiac resynchronization therapy (CRT) may benefit selected DCM patients with a wide QRS complex and reduced ejection fraction. For end-stage cardiomyopathy that no longer responds to medical and device therapy, mechanical support devices (LVADs) and heart transplantation remain options, with the associated costs being a significant consideration.

Living With Cardiomyopathy

Lifestyle measures are an important part of management. Limiting sodium helps control fluid retention, and some patients with advanced heart failure are advised to limit fluids — follow the specific targets your care team sets for you. Moderate, regular exercise benefits most cardiomyopathy patients; the old advice of strict activity restriction has largely been replaced by individualized exercise prescriptions. However, competitive and high-intensity athletics are generally restricted in HCM and ARVC because of the risk of exercise-triggered arrhythmias — decisions here are made individually with your cardiologist.

Alcohol should be avoided entirely in alcohol-related DCM and limited in all cardiomyopathy patients. Cardiac rehabilitation programs provide supervised exercise, education, and support. Daily weight monitoring helps detect early fluid retention so medications can be adjusted before symptoms worsen — report a rapid gain to your team promptly. Getting recommended vaccinations and managing blood pressure, diabetes, and sleep apnea also protect the heart.

Genetic counseling is essential for inherited cardiomyopathies. First-degree relatives (parents, siblings, children) should be offered screening with echocardiography and, when appropriate, genetic testing. Early detection in family members can lead to monitoring and preventive measures — sometimes including an ICD — before symptoms ever develop.

Frequently Asked Questions

Is cardiomyopathy the same as heart failure?

Not exactly. Cardiomyopathy refers to a disease of the heart muscle itself. Heart failure is a clinical syndrome in which the heart cannot pump enough blood to meet the body’s needs. Cardiomyopathy is one of the most common causes of heart failure, but heart failure can also result from coronary artery disease, valve disease, and high blood pressure. Think of cardiomyopathy as the disease and heart failure as its most common consequence.

Can cardiomyopathy be cured?

Some forms are reversible if the underlying cause is removed. Alcohol-related DCM may improve significantly or fully resolve with abstinence. Cardiomyopathy caused by a persistent fast heart rhythm can recover when the arrhythmia is controlled. Takotsubo (stress) cardiomyopathy usually resolves within weeks, and peripartum cardiomyopathy resolves in a substantial share of cases. Genetic and idiopathic cardiomyopathies are generally not curable but can often be effectively managed for many years with medications, devices, and, when necessary, transplantation.

Should my family members be tested if I have cardiomyopathy?

Yes, particularly for HCM, familial DCM, and ARVC, which have a strong genetic basis. First-degree relatives should undergo clinical screening with echocardiography and ECG. If a causative genetic mutation is identified in you, targeted genetic testing of relatives can determine who is at risk and who is not. Screening is typically repeated periodically because these conditions can appear later in life; your cardiology and genetics team will set the schedule, which is usually more frequent for children and adolescents.

Can I exercise with cardiomyopathy?

For most cardiomyopathy patients, moderate exercise is recommended and beneficial. Walking, light cycling, and swimming can improve fitness, mood, and quality of life. The key exceptions are competitive or high-intensity exercise in HCM and ARVC, where vigorous activity can trigger dangerous arrhythmias. Always discuss your exercise plan with your cardiologist, who can give an individualized recommendation based on your specific condition and risk profile.

What is the life expectancy with cardiomyopathy?

This varies enormously depending on the type, severity, cause, and response to treatment. Many patients with well-managed cardiomyopathy live full lives for decades. Survival has improved dramatically with modern therapies — guideline-directed treatment, defibrillators, and new disease-specific drugs have substantially improved outcomes compared with the past. For end-stage disease, heart transplantation can offer many additional years of life. The most reliable prognosis comes from your own cardiologist, who knows the details of your case.

Taking the Next Step

If you have been diagnosed with cardiomyopathy, partner with a cardiologist experienced in managing your specific type. Take your medications exactly as prescribed — every day, not just when you feel unwell — and never stop them on your own. Monitor your weight and symptoms daily, and contact your care team promptly if you notice changes such as rapid weight gain, increasing breathlessness, or new palpitations. If your cardiomyopathy has a genetic basis, make sure your family members are aware and offered screening. And keep the emergency warning signs at the top of this page in mind — acting quickly on fainting, chest pain, or severe breathlessness can be lifesaving.

Modern cardiology has transformed cardiomyopathy from a diagnosis with limited options to one with a robust therapeutic arsenal. New medications, advanced devices, and evolving surgical techniques continue to improve outcomes. The most important thing you can do is stay engaged with your care, stay informed, and stay proactive about managing your heart health.

This article is for general education and is not a substitute for professional medical advice, diagnosis, or treatment. All medication decisions are made by your prescribing clinician; do not start, stop, or change any heart medicine on your own. Information is current as of early 2026 — verify current guidance with your cardiologist.

Sources

• American Heart Association (AHA): Cardiomyopathy; Hypertrophic Cardiomyopathy
• MedlinePlus (U.S. National Library of Medicine): Cardiomyopathy; Sudden Cardiac Arrest
• Centers for Disease Control and Prevention (CDC): Heart Failure and Cardiomyopathy
• American College of Cardiology / American Heart Association: Hypertrophic Cardiomyopathy guideline (2024 update) and Heart Failure guideline
• U.S. Food and Drug Administration (FDA): approvals of mavacamten (2022), aficamten/Myqorzo (December 2025), tafamidis, and acoramidis/Attruby (November 2024)