Cardiomyopathy
Cardiomyopathy is a disease of the heart muscle itself that affects how well the heart pumps and fills with blood. It is a broad term that includes several types—dilated, hypertrophic, restrictive, arrhythmogenic, and stress-induced (takotsubo) cardiomyopathy—each with distinct features, causes, and treatments. Cardiomyopathies can be inherited, acquired (from infections, toxins, or other conditions), or related to broader systemic disease. Cardiac MRI and echocardiography are central tools in diagnosis, alongside ECG, blood tests, and—in selected cases—genetic testing.
What is it?
Cardiomyopathy is a disease of the heart muscle (myocardium) itself rather than a problem caused primarily by blocked coronary arteries, valve disease, or high blood pressure (though these can sometimes coexist or contribute). In cardiomyopathy, the structure or function of the heart muscle is abnormal, affecting how well the heart pumps blood out to the body and fills with blood between beats. Cardiomyopathies can develop slowly over years or, less commonly, acutely.
Several main types of cardiomyopathy are recognized, each with distinct features. Dilated cardiomyopathy (DCM) is characterized by enlargement and weakening of one or both ventricles, leading to reduced pumping function. Causes include genetic factors, prior myocarditis, ischemic heart disease, chronic alcohol use, certain chemotherapies, longstanding rapid heart rhythms, and pregnancy-related (peripartum) cardiomyopathy. Hypertrophic cardiomyopathy (HCM) involves abnormal thickening of the heart muscle—often the wall of the left ventricle and the septum between the ventricles—usually due to genetic mutations affecting heart muscle proteins. Restrictive cardiomyopathy is less common and involves stiffening of the heart muscle, which limits the heart’s ability to fill normally; causes include infiltrative diseases such as amyloidosis, sarcoidosis, hemochromatosis (iron overload), prior radiation, and certain genetic conditions. Arrhythmogenic cardiomyopathy (including arrhythmogenic right ventricular cardiomyopathy, or ARVC) involves replacement of normal heart muscle by fibrous and fatty tissue, leading to abnormal rhythms and often a genetic basis. Takotsubo (stress-induced) cardiomyopathy is a typically reversible weakening of the heart muscle—often triggered by intense emotional or physical stress—that may resemble a heart attack but with characteristic imaging features. Other less common forms include left ventricular noncompaction and various overlap syndromes.
Symptoms depend on the type, severity, and pattern of muscle involvement. Many people with mild cardiomyopathy have no symptoms, particularly early in the disease. As the condition progresses, symptoms may include shortness of breath (especially with exertion or when lying flat), fatigue, reduced exercise tolerance, palpitations, lightheadedness, fainting, chest discomfort, leg swelling, or signs of heart failure. Certain cardiomyopathies, particularly HCM and ARVC, are associated with an increased risk of life-threatening arrhythmias and sudden cardiac death, especially in younger patients and athletes. Some patients are first identified after a family member is diagnosed, leading to screening evaluation.
Diagnosis combines clinical assessment, ECG, blood biomarkers (such as natriuretic peptides), and imaging. Echocardiography is typically the first detailed cardiac imaging test and provides important information about chamber sizes, wall thickness, pumping function, valve function, and pressures within the heart. Cardiac MRI is particularly valuable for cardiomyopathy because it provides detailed anatomical and tissue information, including patterns of scar (late gadolinium enhancement) and abnormal tissue characterization, which often help identify the specific type and underlying cause. ECG and ambulatory rhythm monitoring help identify arrhythmias. Cardiac catheterization may be used in selected cases to assess coronary arteries, pressures, or for biopsy. Blood tests for systemic conditions (such as iron studies for hemochromatosis or specific tests for amyloidosis) are tailored to the suspected cause. Genetic testing, performed with appropriate counseling, is increasingly important for inherited cardiomyopathies and for guiding family screening.
Important to Know
Management of cardiomyopathy is highly individualized and depends on the specific type, the cause, the patient’s symptoms, and the risks involved. Care is typically coordinated by a multidisciplinary team that may include primary care clinicians, cardiologists (often heart failure or inherited cardiomyopathy specialists), electrophysiologists, cardiothoracic surgeons, genetic counselors, and others.
For dilated cardiomyopathy and other forms causing heart failure with reduced pumping function, treatment generally follows guideline-directed medical therapy and may include beta-blockers, ACE inhibitors or ARBs (or ARNI agents), mineralocorticoid receptor antagonists, SGLT2 inhibitors, diuretics, and other medications as appropriate. Treatment of underlying causes—such as control of blood pressure, abstinence from alcohol, treatment of myocarditis, or management of an underlying systemic condition—is essential. Cardiac rehabilitation can be helpful.
Hypertrophic cardiomyopathy is managed based on whether there is obstruction to blood flow out of the left ventricle and on individual symptoms and risk. Beta-blockers and other medications can ease symptoms; newer agents specifically designed for obstructive HCM are available in selected patients. Septal reduction therapies—including surgical myectomy and alcohol septal ablation—may be considered for severe symptoms not controlled with medications.
Restrictive cardiomyopathy is treated based on the underlying cause; examples include specific therapies for amyloidosis, treatment of iron overload, immunosuppression for sarcoidosis, and supportive heart failure care. Arrhythmogenic cardiomyopathy management focuses on arrhythmia prevention, often including activity restriction and implantable defibrillators in higher-risk patients.
Arrhythmia management is critical in many cardiomyopathies. Patients with significant risk of life-threatening rhythms may benefit from implantable cardioverter-defibrillators (ICDs), and some benefit from cardiac resynchronization therapy (CRT) when there is dyssynchronous heart function and reduced ejection fraction. Catheter ablation may be considered for certain arrhythmias.
Family screening is an important consideration in genetic cardiomyopathies (such as HCM and ARVC) and many forms of DCM. First-degree relatives may be advised to undergo clinical evaluation, imaging, and, when appropriate, genetic testing.
Lifestyle measures—including a heart-healthy diet, limited alcohol, weight management, treatment of sleep apnea, and individualized exercise guidance—are important components of care. Some cardiomyopathies require specific activity restrictions, particularly when there is risk of arrhythmias or significant obstruction.
In severe, advanced cardiomyopathy, options may include mechanical circulatory support (such as ventricular assist devices) and heart transplantation. Decisions about advanced therapies are made in specialized centers.
Red flag symptoms include severe or worsening shortness of breath, severe chest pain, fainting, sustained rapid or irregular heart rate, severe leg swelling, sudden weight gain, signs of stroke, or sudden collapse. These warrant prompt or urgent medical evaluation.