Understanding Dilated Cardiomyopathy: Causes, Symptoms, Treatment and Prevention

Dilated cardiomyopathy (DCM) occurs when the heart’s main pumping chamber, the left ventricle, becomes enlarged and weakened, losing its ability to pump blood efficiently. If left untreated, the condition can lead to heart failure and other serious complications, such as blood clots.

DCM is a relatively common type of heart disease. Although it is most frequently diagnosed in middle-aged men, it can affect people of all ages and genders. With early detection and appropriate management, it is often possible to slow its progression. Therefore, recognizing and understanding dilated cardiomyopathy is important for maintaining good heart health and quality of life.

What Are the Types of Dilated Cardiomyopathy?

DCM is classified based on its underlying cause. The main types are:

• Familial (genetic) dilated cardiomyopathy – Caused by an inherited genetic mutation that affects heart muscle function, familial DCM is often diagnosed in individuals with a family history of cardiomyopathy or sudden cardiac death (SCD).
• Idiopathic dilated cardiomyopathy – The most common type of DCM, idiopathic dilated cardiomyopathy sometimes runs in families, which suggests a genetic component. However, its precise cause is unknown.
• Inflammatory (myocarditis-related) dilated cardiomyopathy – Inflammatory DCM is associated with certain viral infections, autoimmune diseases and other inflammatory conditions that damage the heart muscle.
• Ischemic dilated cardiomyopathy – Often linked to coronary artery disease or previous heart attacks, ischemic DCM results from reduced blood flow to the heart, which can weaken the left ventricle over time.
• Peripartum cardiomyopathy – This rare form of heart disease, which can affect women during the last trimester of pregnancy or in the months following childbirth, may be related to hormonal fluctuations, inflammation or genetic predisposition.
• Tachycardia-induced dilated cardiomyopathy – Caused by prolonged periods of rapid or irregular heartbeats (arrhythmias), tachycardia-induced DCM may resolve with treatment of the underlying arrhythmia.
• Toxic dilated cardiomyopathy – Caused by long-term exposure to toxins that affect the heart, toxic DCM can result from excessive alcohol consumption, illicit drug use or chemotherapy. Heart function may improve with the avoidance of these harmful substances.

What Causes Dilated Cardiomyopathy and What Are the Risk Factors?

DCM results from heart muscle damage that weakens the left ventricle, causing it to struggle to pump blood. Several factors may contribute to its development, including:

• Autoimmune disorders – Conditions such as lupus and rheumatoid arthritis can trigger inflammation that affects the heart.
• Certain viral infections and myocarditis – Some viruses can inflame the heart muscle, leading to long-term damage.
• Coronary artery disease and heart attacks – Reduced blood supply to the heart can weaken the muscle over time.
• Endocrine disorders – Thyroid disease, diabetes and other hormonal imbalances can contribute to heart muscle weakening.
• High blood pressure – Chronic hypertension forces the heart to work harder, which can lead to left ventricle enlargement and weakening.
• Inherited gene mutations – Up to one-third of DCM cases run in families, suggesting a genetic link.
• Persistent arrhythmias – Prolonged irregular heart rhythms, such as atrial fibrillation (Afib), can gradually weaken the heart muscle.
• Pregnancy – Some women develop peripartum DCM during late pregnancy or after delivery, possibly due to hormonal or immune-related changes.
• Toxins and substance abuse – Long-term alcohol consumption, illicit drug use and certain chemotherapy drugs can damage heart tissue.

Risk factors for dilated cardiomyopathy include:

• Chronic stress and unhealthy lifestyle habits – Smoking, excessive alcohol consumption and lack of physical activity can all contribute to heart disease.
• Family history – Individuals with one or more close relatives who were diagnosed with DCM are at heightened risk.
• Gender and age – DCM is most commonly diagnosed in men between ages 20 and 60.
• Nutritional deficiencies – A lack of essential nutrients, such as thiamine (vitamin B1), can slowly weaken the heart muscle.
• Obesity – Carrying excess body weight increases the burden on the heart.
• Uncontrolled diabetes – Poorly managed diabetes can contribute to heart damage.

What Are the Warning Signs and Symptoms of Dilated Cardiomyopathy?

DCM often develops gradually. As the condition progresses and the heart’s pumping capacity declines, symptoms may become noticeable. Recognizing the early warning signs is essential to ensure a timely diagnosis and treatment.

Common symptoms of dilated cardiomyopathy include:

• Arrhythmias – Palpitations, fluttering sensations or a racing heart
• Chest pain – Discomfort resulting from reduced blood flow to the heart muscle, particularly with physical exertion
• Dizziness or lightheadedness – Fainting or near-fainting episodes caused by diminished blood flow to the brain
• Fatigue and weakness – Persistent tiredness due to insufficient blood flow to muscles and organs
• Persistent coughing or wheezing – Caused by fluid buildup in the lungs, known as pulmonary congestion
• Shortness of breath (dyspnea) – Difficulty breathing, especially during physical activity or while lying down
• Swelling (edema) – Fluid retention in the legs, ankles, feet or abdomen caused by poor blood circulation

Severe DCM symptoms require immediate medical attention. These include:

• Extreme dyspnea – A struggle to breathe, even while at rest
• Sudden fainting or loss of consciousness – May indicate a serious heart rhythm issue
• Persistent chest pain – Could signal a heart attack or worsening heart failure

How Is Dilated Cardiomyopathy Diagnosed?

The diagnostic process for DCM typically begins with a clinical evaluation. The physician will review the patient’s symptoms, family history of heart disease and other potential risk factors, such as hypertension, infection and exposure to toxins. Next, the physician will perform a thorough physical examination to check for signs of heart failure, such as leg swelling, arrhythmias and fluid buildup in the lungs.

To assess the patient’s heart function, the physician may order one or more specialized diagnostic tests, such as:

• Blood work – Specialized blood tests can detect underlying conditions, such as infections and thyroid disorders, and biomarkers of cardiovascular health.
• Cardiac catheterization and angiography – This minimally invasive procedure allows the physician to examine blood flow through the coronary arteries and measure heart function.
• Cardiac magnetic resonance imaging (MRI) – An MRI scan can provide detailed images of the heart, allowing the physician to assess its structure and function and check for muscle damage and scarring.
• Chest X-ray – Radiographic images can help the physician identify heart enlargement or fluid buildup in the lungs.
• Echocardiogram – The primary imaging test for diagnosing DCM, an echocardiogram uses ultrasound waves to help the physician assess the heart’s size, function and pumping efficiency.
• Electrocardiogram (ECG/EKG) – An EKG measures the electrical activity of the heart, which can help the physician detect arrhythmias and signs of heart strain.
• Genetic testing – For individuals with a family history of DCM, genetic testing may be recommended to identify inherited genetic mutations.
• Stress test – Also known as an exercise stress test, this procedure can help the physician evaluate the heart’s response to exertion and identify areas of reduced blood flow.

How Is Dilated Cardiomyopathy Treated?

DCM treatment focuses on managing symptoms, improving heart function and preventing complications, such as heart failure and arrhythmias. The specific treatment plan is tailored to the severity of the condition and its underlying cause, typically involving a combination of medications, lifestyle modifications and medical procedures when necessary.

Medications that may be prescribed to treat dilated cardiomyopathy include:

• Angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) – Can decrease the heart’s workload by relaxing blood vessels
• Aldosterone antagonists – Can help regulate the fluid/electrolyte balance while protecting the heart from further damage
• Antiarrhythmic drugs – Can control irregular heartbeats
• Anticoagulants (blood thinners) – Can prevent blood clots in individuals at high risk of stroke or embolism
• Beta-blockers – Can slow the heart rate, reduce strain on the heart and improve its overall function
• Diuretics – Can reduce fluid buildup to ease swelling and shortness of breath

Many patients with dilated cardiomyopathy benefit from making positive lifestyle changes, such as:

• Consuming a heart-healthy diet – Reducing sodium, saturated fats and processed foods can help control blood pressure and fluid retention.
• Getting regular exercise – Light to moderate physical activity (as guided by a physician) can strengthen the heart and improve cardiovascular health.
• Maintaining a healthy body weight – Weight control can minimize strain on the heart.
• Managing underlying conditions – Proper management of diabetes, hypertension and thyroid disorders can help keep DCM symptoms from worsening.
• Quitting tobacco and alcohol – Smoking cessation and alcohol abstinence can help prevent further heart damage.

In some cases, medical devices and procedures may be considered, such as:

• Implantable cardioverter defibrillator (ICD) – May be recommended for a patient at risk of life-threatening arrhythmias
• Cardiac resynchronization therapy (CRT) – Can improve coordination among heart chambers in a patient with severe heart failure
• Left ventricular assist device (LVAD) – Can help the heart circulate oxygen-rich blood more effectively
• Heart transplant – May be considered to address severe DCM that does not respond to other treatments

What Are the Possible Complications and Long-Term Effects of Dilated Cardiomyopathy?

If DCM is left untreated—or if the condition progresses despite medical treatment—complications may arise. The severity can vary depending on the degree of heart dysfunction and the presence of underlying conditions. Possible complications and long-term effects of dilated cardiomyopathy include:

• Arrhythmias – DCM increases the risk of irregular heart rhythms, such as Afib and ventricular tachycardia, which can cause palpitations, dizziness and fainting. Severe arrhythmias can lead to sudden cardiac arrest.
• Blood clots and stroke – A weakened heart may not pump blood efficiently, increasing the risk of clot formation. If a clot travels to the brain, it may cause a stroke.
• Heart failure – As the heart weakens, blood circulation declines, which can lead to fluid buildup in the lungs and other parts of the body. Symptoms such as shortness of breath, swelling, and fatigue can significantly impact daily activities.
• Heart valve problems – When the heart becomes enlarged, the mitral and tricuspid valves may stretch, allowing blood to flow backward (regurgitation). This can worsen heart failure symptoms and may require additional treatment.
• Organ damage – Poor circulation due to heart failure can reduce oxygen supply to vital organs, potentially leading to kidney or liver dysfunction.
• Sudden cardiac arrest – In some cases, life-threatening arrhythmias can cause the heart to suddenly stop beating. High-risk patients may benefit from an ICD to help prevent this outcome.

How Can Dilated Cardiomyopathy Be Prevented?

Some DCM cases are linked to genetic factors and cannot be entirely prevented. However, certain lifestyle choices and medical interventions can help reduce the risk or slow the progression of dilated cardiomyopathy. Heart-healthy strategies include:

• Eating a balanced diet – A diet rich in fruits, vegetables, whole grains, lean proteins and healthy fats supports heart health and reduces the risk of conditions that may contribute to DCM.
• Exercising regularly – Engaging in moderate physical activity can help maintain cardiovascular fitness (it is important to consult a physician before starting an exercise program).
• Having routine medical check-ups – Periodic physical exams and heart screenings can help detect risk factors before they develop into serious issues.
• Limiting alcohol consumption – Excessive drinking can weaken the heart muscle over time, increasing the risk of DCM.
• Managing underlying health conditions – Keeping blood pressure within a healthy range can reduce strain on the heart caused by hypertension. Managing blood sugar levels can lower the risk of diabetes-related heart complications.
• Monitoring family history and seeking medical advice – Individuals with a family history of DCM should consider genetic testing and regular heart evaluations to detect early signs of the disease.
• Quitting tobacco – Smoking damages blood vessels and increases the risk of heart failure and other cardiovascular diseases.
• Treating infections promptly – Some viral infections can lead to myocarditis, which may contribute to DCM. Seeking early treatment can help prevent lasting heart damage.

Living With Dilated Cardiomyopathy

Living with DCM usually involves ongoing management to control symptoms and prevent complications. Many individuals can maintain a good quality of life with medications, lifestyle adjustments and regular medical checkups. However, some may experience fatigue, shortness of breath and activity limitations due to reduced heart function. In severe cases, advanced treatment, such as an implantable device or heart transplant, may be necessary. Regular monitoring, a heart-healthy lifestyle and adherence to prescribed treatments are essential to managing the condition and improving the long-term outcome.

Benefit From World-Class Care at TGH

Whether you have symptoms of dilated cardiomyopathy or you have already received a diagnosis, you are welcome to seek care at Tampa General Hospital's Heart and Vascular Institute, where you can benefit from leading-edge treatments and the expertise of a full team of specialists dedicated to your heart health. TGH is committed to helping you manage your cardiac condition and improve your quality of life. Our commitment to world-class care has been recognized by U.S. News & World Report, who named us One of the Nation's Best Hospitals for Heart & Vascular Care and a High Performing Hospital for Heart Attack and Heart Failure treatment for 2024-25.

If you would like to talk with an expert at TGH, contact us at (813) 844-3900 or email heart-vascular@tgh.org to request an appointment.