Cardiomyopathy

Your heart is essentially a muscular pump, contracting rhythmically to circulate blood throughout your body. Cardiomyopathy is a disease of this heart muscle itself—it becomes too weak, too thick, or too stiff to pump blood effectively. Unlike coronary artery disease where blocked arteries are the problem, cardiomyopathy affects the muscle tissue directly. Some forms are inherited and run in families, while others develop from infections, alcohol abuse, chemotherapy, or unknown causes. The condition ranges from mild cases requiring only monitoring to severe disease causing heart failure and sudden death.

Overview

Cardiomyopathy is a disease where the heart muscle becomes abnormal, making it harder for your heart to pump blood to the rest of your body. The muscle itself is damaged or dysfunctional, not the arteries supplying blood to it.

There are three main types. Dilated cardiomyopathy is the most common form. The heart muscle stretches and becomes thin, enlarging the heart chambers—particularly the left ventricle. As the muscle thins and stretches, it becomes weaker and can’t contract forcefully. Hypertrophic cardiomyopathy involves abnormal thickening of the heart muscle, especially the wall separating the two lower chambers. This thickened muscle stiffens the heart and can block blood flow out of the heart. Restrictive cardiomyopathy makes the heart muscle rigid and less elastic, so it can’t expand properly to fill with blood between beats. This is the least common type.

Each type affects heart function differently, but all can lead to heart failure, rhythm problems, and other serious complications. Some people have mild disease causing no symptoms for years, while others develop severe symptoms quickly.

The condition can be inherited, meaning it’s passed down through families due to genetic mutations. Many cases appear without family history, developing from various causes including infections, alcohol, chemotherapy drugs, or unknown reasons.

Cardiomyopathy affects people of all ages, from infants to elderly adults. Some forms are more common in specific age groups—hypertrophic cardiomyopathy often appears in young adults, while dilated cardiomyopathy peaks in middle age.

Heart failure develops in many people with cardiomyopathy as the weakened or stiffened heart can’t meet the body’s demands. Dangerous heart rhythms (VT, VFib) are common because abnormal muscle creates electrically unstable tissue. Blood clots can form in dilated, poorly contracting chambers, potentially causing strokes.

Causes

Different types of cardiomyopathy have different causes, though sometimes no cause is found.

• Inherited genetic mutations cause many cases, particularly hypertrophic cardiomyopathy. If you have a parent with genetic cardiomyopathy, you have a 50% chance of inheriting the abnormal gene. Not everyone with the gene develops disease—some carry the mutation without symptoms. Family screening is important when genetic forms are diagnosed.
• Viral infections of the heart muscle, called myocarditis, can damage tissue and lead to dilated cardiomyopathy. Common viruses include those causing colds and flu, though many viruses can affect the heart. Most people recover completely, but some develop permanent damage.
• Long-term excessive alcohol consumption directly damages heart muscle, causing alcoholic cardiomyopathy. This typically requires years of heavy drinking—more than 4-5 drinks daily for women or 7-8 for men. Stopping alcohol can sometimes improve or even reverse the condition if caught early.
• Chemotherapy drugs, particularly certain ones used for breast cancer and lymphoma, can damage heart muscle. Radiation therapy to the chest also increases risk. This is a known complication weighed against cancer treatment benefits.
• Pregnancy-related cardiomyopathy, called peripartum cardiomyopathy, develops in the last month of pregnancy or within five months after delivery. The cause isn’t fully understood. Many women recover, but some develop permanent heart damage.
• High blood pressure, if severe and uncontrolled for many years, can lead to cardiomyopathy as the heart muscle thickens from constantly working against high pressure.
• Heart valve disease forces the heart to work harder, sometimes leading to muscle damage over time.
• Chronic rapid heart rhythms can weaken the heart muscle if they persist for months or years.
• Thyroid disease, both overactive and underactive thyroid, can cause cardiomyopathy.
• Iron overload diseases like hemochromatosis deposit iron in heart tissue, damaging muscle.
• Certain autoimmune diseases can affect heart muscle.
• Nutritional deficiencies, particularly severe thiamine deficiency, cause cardiomyopathy, though this is rare in developed countries.
• Cocaine and methamphetamine use damages heart muscle.
• In many cases, despite thorough evaluation, no cause is identified. These cases are called idiopathic cardiomyopathy.

Symptoms

Many people with early cardiomyopathy have no symptoms. As the disease progresses, symptoms typically develop gradually, though sometimes they appear suddenly.

• Shortness of breath is the most common symptom across all types. Initially noticeable only during activity like climbing stairs or exercising, it progressively worsens. Eventually, even minor activities or rest cause breathlessness. Many people sleep propped up on pillows because lying flat makes breathing difficult.
• Fatigue and weakness are profound. You feel exhausted with minimal activity. Simple tasks like showering or getting dressed become tiring. This isn’t just feeling tired—it’s deep exhaustion that doesn’t improve with rest.
• Swelling in the ankles, feet, legs, and sometimes abdomen develops as fluid backs up. This swelling is typically worse at the end of the day and improves somewhat overnight.
• Dizziness or lightheadedness occurs when the heart can’t pump enough blood to meet your body’s needs, particularly during activity or position changes.
• Chest pain or pressure can occur, particularly with hypertrophic cardiomyopathy where thickened muscle doesn’t receive adequate blood flow.
• Palpitations or awareness of your heartbeat are common as cardiomyopathy leads to rhythm problems.
• Fainting is concerning, particularly with hypertrophic cardiomyopathy. It can indicate dangerous rhythm problems and increased risk for sudden death.
• Rapid heartbeat even at rest suggests the heart is working harder to maintain adequate blood flow.

Some people discover cardiomyopathy through routine examinations or testing for other reasons before any symptoms develop. Others experience sudden cardiac arrest as their first sign of disease, which is why family screening is so important in genetic forms.

Diagnosis

Diagnosing cardiomyopathy involves determining that heart muscle is abnormal, identifying which type you have, and finding the underlying cause if possible.

• Your medical history provides important clues. Your doctor asks about symptoms, family history of heart disease or sudden death, alcohol use, medications, recent infections, and other conditions.
• Physical examination includes listening to your heart and lungs, checking for swelling, and measuring blood pressure. Abnormal heart sounds, fluid in lungs, or enlarged liver suggest heart failure from cardiomyopathy.
• Echocardiography is the main test for diagnosing cardiomyopathy. This ultrasound shows heart size, wall thickness, how well the heart pumps, valve function, and blood flow patterns. It distinguishes between dilated, hypertrophic, and restrictive types and measures how much blood the heart pumps with each beat.
• Electrocardiogram records electrical activity, often showing abnormal patterns with cardiomyopathy and identifying rhythm problems.
• Chest X-ray shows heart size and whether fluid has accumulated in the lungs.
• Blood tests check for conditions causing or contributing to cardiomyopathy—thyroid function, iron levels, infection markers, and stress hormone levels indicating heart strain.
• Cardiac MRI provides detailed images of heart structure and identifies scar tissue or inflammation. This is particularly useful when echocardiography doesn’t provide adequate information.
• Stress testing evaluates how your heart responds to exertion and can provoke symptoms or rhythm problems not apparent at rest.
• Cardiac catheterization directly measures pressures inside heart chambers and can rule out coronary artery disease as a cause of heart muscle dysfunction.
• Heart muscle biopsy, where tiny tissue samples are removed through a catheter, is sometimes performed if specific diseases are suspected, particularly infiltrative conditions.
• Genetic testing is recommended when inherited cardiomyopathy is suspected. Identifying specific mutations helps predict disease progression and guides family screening.

Treatment

Treatment depends on the type of cardiomyopathy, severity, symptoms, and whether complications have developed.

• For dilated cardiomyopathy, medications improve heart function and symptoms. Standard heart failure drugs including ACE inhibitors or ARBs help the heart pump more efficiently. Beta-blockers improve heart function and survival. Diuretics reduce fluid retention. Newer medications like SGLT2 inhibitors significantly improve outcomes. The medication regimen is typically lifelong and must be taken consistently even when you feel well.
• For hypertrophic cardiomyopathy, beta-blockers or calcium channel blockers help the heart relax and improve filling. Newer medications specifically targeting thickened heart muscle are now available. Avoiding dehydration and limiting intense competitive sports is important.
• For restrictive cardiomyopathy, treatment focuses on managing symptoms and addressing underlying causes when identified. Options are more limited than for other types.
• Devices help many people. Implantable defibrillators prevent sudden death from dangerous rhythms and are recommended for people at high risk. Pacemakers help if heart rate becomes too slow. Special pacemakers that coordinate contractions improve heart function in some people with dilated cardiomyopathy.
• For severe hypertrophic cardiomyopathy causing obstruction, procedures can help. Septal myectomy is surgery removing excess thickened muscle. Alcohol septal ablation destroys a small amount of thickened muscle through a catheter. Both procedures improve blood flow and symptoms.
• Treating underlying causes is crucial. Stopping alcohol completely if alcohol caused the disease. Medications for high blood pressure or thyroid problems. Iron removal if hemochromatosis is present.
• For advanced cardiomyopathy not responding to other treatments, mechanical heart pumps can support circulation, either temporarily as a bridge to transplant or permanently. Heart transplantation remains the ultimate treatment for end-stage disease in appropriate candidates, though donor hearts are limited.

Family screening is essential with genetic types. Close relatives should undergo evaluation including echocardiography and possibly genetic testing.

What Happens If Left Untreated

Untreated cardiomyopathy progressively worsens, though the rate varies enormously between individuals.

• Heart failure develops or worsens as the heart muscle can’t maintain adequate blood flow. Symptoms become increasingly severe until even rest provides no relief. Quality of life deteriorates dramatically.
• Dangerous heart rhythms become more common as abnormal muscle creates electrically unstable tissue. These can cause sudden cardiac arrest and death without immediate treatment.
• Sudden cardiac death can occur, particularly with hypertrophic cardiomyopathy. This sometimes happens during or shortly after intense physical activity in young people who didn’t know they had the condition.
• Blood clots form in enlarged, poorly contracting chambers, potentially causing strokes when clots travel to the brain.
• Heart valves can malfunction as heart chambers dilate and distort, adding valve problems to muscle problems.
• Life expectancy shortens significantly with severe untreated cardiomyopathy. Once symptoms develop, particularly with dilated cardiomyopathy, survival without treatment is measured in years.
• However, with proper treatment, many people with cardiomyopathy live for decades. Early diagnosis and treatment dramatically improve outcomes.

What to Watch For

If you have cardiomyopathy or are at risk, certain symptoms require prompt attention.

• Seek emergency care for fainting, particularly with hypertrophic cardiomyopathy. This can indicate dangerous rhythms.
• Call emergency services for severe chest pain, especially if accompanied by shortness of breath or sweating.
• Contact your doctor promptly for worsening shortness of breath, particularly if it comes on suddenly or occurs with less activity than before.
• Report new or worsening swelling in your legs, ankles, or abdomen.
• Notify your doctor about new palpitations or feeling that your heart is beating irregularly or too fast.
• Watch for rapid weight gain—several pounds over a few days—which indicates fluid retention.
• If you develop symptoms during exercise that weren’t present before—chest pain, severe shortness of breath, or extreme fatigue—stop the activity and contact your doctor.
• Report persistent cough or wheezing, particularly if worse when lying down.
• If you have a family history of cardiomyopathy or sudden cardiac death, undergo screening even without symptoms. Early detection saves lives.

Living with Cardiomyopathy

Managing cardiomyopathy involves lifestyle adjustments and following your treatment plan.

• Take all medications exactly as prescribed. These drugs prevent progression and improve survival, even if you don’t feel immediate effects. Never stop medications without consulting your doctor.
• Monitor your weight daily. Sudden increases indicate fluid retention requiring medication adjustment.
• Limit sodium intake to reduce fluid retention. Most people with cardiomyopathy should consume less than 2,000 mg daily.
• Restrict alcohol completely if it contributed to your cardiomyopathy. Even if alcohol wasn’t the cause, limit intake as it can worsen heart function.
• Exercise appropriately based on your doctor’s recommendations. Many people with cardiomyopathy benefit from regular moderate exercise, but intense competitive sports should be avoided, particularly with hypertrophic cardiomyopathy.
• Stay hydrated but avoid excessive fluids if you have severe heart failure. Your doctor provides specific guidance.
• Manage stress through relaxation techniques and adequate sleep.
• Get vaccinated against flu and pneumonia to prevent infections that stress the heart.
• If you have an implantable defibrillator, follow all instructions about device checks and what to do if it delivers shocks.
• Inform family members about genetic screening recommendations if your cardiomyopathy is inherited.
• Women with cardiomyopathy should discuss pregnancy plans with their cardiologist. Some types significantly increase pregnancy risks.
• Regular follow-up appointments are essential for monitoring disease progression and adjusting treatment.

Key Points

• Cardiomyopathy is disease of the heart muscle itself, not the arteries supplying blood to it. The muscle becomes too weak, too thick, or too stiff to pump effectively.
• Three main types exist—dilated, hypertrophic, and restrictive—each affecting the heart differently but all potentially serious.
• Many cases are inherited, making family screening crucial when genetic forms are diagnosed. If a close relative has cardiomyopathy, you should be evaluated.
• Early disease often causes no symptoms. By the time symptoms appear, significant muscle abnormalities are usually present. This is why screening at-risk individuals is so important.
• Treatment has improved dramatically. Medications, devices, and procedures now help most people with cardiomyopathy live longer, better-quality lives.
• Sudden cardiac death is a real risk, particularly with hypertrophic cardiomyopathy. Implantable defibrillators prevent this tragedy in high-risk individuals.
• Lifestyle modifications matter. Avoiding alcohol, managing weight, limiting sodium, and exercising appropriately all help manage the condition.
• Genetic testing and family counseling are important when inherited forms are suspected. Identifying at-risk family members allows early intervention.
• Pregnancy requires special consideration in women with cardiomyopathy. Some types create significant risks requiring careful monitoring and sometimes treatment adjustments.
• Work closely with a cardiologist experienced in treating cardiomyopathy. This complex condition requires specialized knowledge about when to use specific medications, when devices are needed, and when more aggressive interventions become necessary. While cardiomyopathy is a serious diagnosis, modern treatments allow most people to manage the condition successfully. The key is early diagnosis, appropriate treatment, and careful ongoing monitoring to prevent complications and maintain the best possible quality of life.

Reference: Cardiomyopathy