Enlarged Heart: Symptoms, Causes, and Treatment
Updated: 3 days ago
Medically reviewed by [Dr. Baraa Alnahhal, MD](https://www.rinnit.com/dr-baraa-alnahhal). Last reviewed October 17, 2026. This content is for educational purposes and is not medical advice.
Quick Answer
An enlarged heart, or cardiomegaly, is a heart that appears enlarged on an imaging test such as a chest X-ray; it is a sign of another condition, not a disease itself. The main warning sign is shortness of breath, especially lying flat. Causes include heart muscle damage, valve disease and high blood pressure. Treatment depends on the cause.
What the research says
SGLT2 inhibitors reduce heart failure hospitalizations across the board. A meta-analysis of five randomized trials (21,947 people with heart failure) found these drugs lowered the risk of cardiovascular death or hospital admission for heart failure (hazard ratio 0.77, 95% CI 0.72 to 0.82), with consistent benefit regardless of ejection fraction (Vaduganathan et al., The Lancet, 2022).
Heart failure medicines should usually continue even after the heart recovers. In a randomized trial of 51 people whose dilated cardiomyopathy had recovered, 11 of 25 (44%) who stopped their medicines relapsed within 6 months, compared with none of the 26 who continued (Halliday et al., The Lancet, 2019).
Genes matter in the most severe cases. Among 1,198 people with dilated cardiomyopathy, pathogenic or likely pathogenic gene variants were found in 26.2% of those who needed a heart pump or transplant versus 15.0% of those with no device (odds ratio 2.3, 95% CI 1.5 to 3.6) (Hofmeyer et al., Circulation, 2023).
What Is an Enlarged Heart?
An enlarged heart (cardiomegaly) isn't a disease, but rather a sign of another condition. The term refers to an enlarged heart seen on any imaging test, including a chest X-ray [1].
If the heart weakens, as it can with heart failure, it begins to enlarge. This forces the heart to work harder to pump blood to the rest of the body. Heart damage and certain types of heart disease can cause an enlarged heart [1].
Sometimes short-term stress on the body, such as pregnancy, can cause the heart to get larger. Depending on the condition, an enlarged heart may be temporary or permanent [1].
Treatment may include medications, medical procedures, or surgery, and it always targets the underlying cause [1].
Symptoms: Warning Signs of an Enlarged Heart
In some people, an enlarged heart causes no signs or symptoms at all. Others may experience the following [1]:
Shortness of breath, especially while lying flat
Waking up short of breath
Irregular heart rhythm (arrhythmia)
Swelling (edema) in the belly or in the legs
When to Seek Emergency Care
An enlarged heart may be easier to treat when it is detected early, so talk to a healthcare provider if you have concerns about your heart [1].
Call 911 or your local emergency number if you have signs and symptoms of a potential heart attack [1]:
Chest pain
Discomfort in other areas of the upper body, including one or both arms, the back, neck, jaw, or stomach
Severe shortness of breath
Fainting
Causes: What Makes the Heart Grow Larger
An enlarged heart can be caused by damage to the heart muscle or by any condition that makes the heart pump harder than usual, including pregnancy. Sometimes the heart gets larger and becomes weak for unknown reasons. This condition is called idiopathic cardiomyopathy [1].
Cause | How it enlarges the heart |
Congenital heart defect | A heart problem present at birth; structure and function issues cause the muscle to get larger and weak [1] |
Heart attack damage | Scarring and structural damage make pumping harder; strain leads to heart swelling and eventually heart failure [1] |
Cardiomyopathy | Diseases of the heart muscle that often make it rigid or thick, making pumping harder [1] |
Pericardial effusion | Fluid builds up in the sac around the heart and looks like enlargement on a chest X-ray [1] |
Heart valve disease | Damage to any of the four valves interrupts blood flow and lets the chambers grow larger [1] |
High blood pressure | The heart pumps harder to deliver blood; strain makes the muscle grow larger and become weak [1] |
Pulmonary hypertension | High pressure in the lung arteries forces the heart to work harder, which can thicken or enlarge the right side [1] |
Anemia | A low red blood cell count forces the heart to pump more blood to make up for missing oxygen [1] |
Thyroid disorders | Both underactive and overactive thyroid glands can lead to heart problems, including enlargement [1] |
Hemochromatosis | Excess iron builds up in organs including the heart and can swell the lower left chamber [1] |
Cardiac amyloidosis | A rare disease in which amyloid protein deposits cause irreversible thickening of the heart wall [1] |
Not all causes are dangerous. In some athletes, the heart becomes enlarged in response to frequent, prolonged aerobic exercise. This type of enlarged heart is usually not considered a disease and does not need treatment. Similarly, some people have extra fat around the heart that can appear on a chest X-ray; unless other heart conditions are present, no treatment is necessary [1].
Risk Factors
The following factors can increase the risk of an enlarged heart [1]:
Risk factor | Why it matters |
Family history of cardiomyopathy | Some types run in families; tell your provider if a parent or sibling has a thick, rigid, or enlarged heart [1] |
High blood pressure | A measurement higher than 140/90 millimeters of mercury [1] |
Other heart diseases | Any problem affecting the heart, including congenital defects or valve disease, may lead to enlargement [1] |
Following a healthy lifestyle and having regular health checkups help manage heart disease and its risk of causing enlargement [1].
Complications: Why a Larger Heart Matters
The risk of complications depends on which part of the heart is affected and on the cause. Possible complications include [1]:
Complication | What happens |
Heart failure | If the left lower chamber (left ventricle) becomes enlarged, the heart can't pump the proper amount of blood through the body [1] |
Blood clots | Clots may form in the lining of the heart; one from the right side can travel to the lungs (pulmonary embolism), and any clot that blocks blood flow could cause a heart attack or stroke [1] |
Leaky heart valve (regurgitation) | Enlargement may prevent the mitral and tricuspid valves from closing, so blood leaks backward and creates a heart murmur that should be monitored [1] |
Cardiac arrest and sudden death | An irregular heartbeat that beats too fast or too slow may lead to fainting, cardiac arrest, or sudden death [1] |
Prevention: Protecting the Heart
Telling a healthcare provider about any family history of cardiomyopathy matters. When diagnosed early, proper treatment of the underlying condition may prevent the enlarged heart from getting worse [1].
A heart-healthy lifestyle can help prevent or manage conditions that can lead to an enlarged heart. Take these steps [1]:
Monitor and manage high blood pressure, high cholesterol, and diabetes.
Take any prescribed medications as directed.
Eat a nutritious, balanced diet.
Get regular exercise.
Avoid or limit alcohol.
Don't smoke.
Don't use illegal drugs.
How an Enlarged Heart Is Diagnosed
To diagnose an enlarged heart, a healthcare provider usually performs a physical exam and asks about symptoms and medical history. Several tests may follow [2]:
Test | What it shows |
Blood tests | Help confirm or rule out conditions that cause heart enlargement; if chest pain or heart attack signs are present, they check for substances released by damaged heart muscle [2] |
Chest X-ray | Shows the condition of the lungs and heart; if the heart looks enlarged, other tests confirm whether the enlargement is real and find the cause [2] |
Electrocardiogram (ECG or EKG) | A quick, painless test with sticky electrodes on the chest, arms, and legs that measures electrical activity; patterns can reveal a thickened heart muscle (hypertrophy) [2] |
Echocardiogram | A noninvasive sound-wave test that images the heart's size, structure, and motion, shows blood flow through the chambers, and shows how well the heart is working [2] |
Exercise or stress tests | Treadmill or stationary bike while the heart is monitored; medications can mimic the effect of exercise for those unable to exercise [2] |
Cardiac CT scan or MRI | Detailed cross-sectional images made by an X-ray tube rotating around the body (CT) or a magnetic field and radio waves (MRI) [2] |
Cardiac catheterization | A thin tube is threaded through a blood vessel in the arm or groin to a heart artery; injected dye makes the arteries visible on X-ray, chamber pressure is measured, and sometimes a small tissue sample is removed for biopsy [2] |
Results from these tests help the care team pinpoint the cause and build a treatment plan [2].
Treatment Options
Treatment of an enlarged heart depends on what is causing the heart problem [2].
Medications
If cardiomyopathy or another type of heart condition is the cause, a healthcare provider may recommend the following [2]:
Medication | What it does |
Diuretics | Reduce sodium and water in the body, which can help lower blood pressure [2] |
Other blood pressure drugs | Beta blockers, ACE inhibitors, or ARBs lower blood pressure and improve heart function [2] |
Blood thinners (anticoagulants) | Reduce the risk of blood clots that could cause a heart attack or stroke [2] |
Heart rhythm drugs (anti-arrhythmics) | Help control the heartbeat [2] |
Surgery and Other Procedures
If medications are not enough, medical devices and surgery may be needed [2]:
Procedure | What is involved |
Pacemaker | A small device implanted near the collarbone sends electrical impulses through wires into the heart when the heart rate is too slow or stops, keeping a steady beat [2] |
Implantable cardioverter-defibrillator (ICD) | A battery-powered unit under the skin near the collarbone continuously monitors the rhythm and delivers low- or high-energy shocks to reset it when an irregular heartbeat is detected; used for serious arrhythmias or risk of sudden death [2] |
Heart valve surgery | Repair or replacement of the affected valve when valve disease causes the enlargement [2] |
Coronary bypass surgery | Open-heart surgery that reroutes blood flow around a clogged artery when a blockage in the coronary arteries is the cause [2] |
Left ventricular assist device (LVAD) | An implantable mechanical pump that helps the heart pump; used while waiting for a transplant or as long-term treatment when a transplant is not possible [2] |
Heart transplant | The final treatment option when the condition cannot be treated any other way; because of the shortage of donor hearts, even critically ill people may wait a long time [2] |
Self-Care: A Heart-Healthy Lifestyle
If you have an enlarged heart or any type of heart disease, your provider will likely recommend a heart-healthy lifestyle. Such a lifestyle typically includes [2]:
Reducing or avoiding salt.
Limiting saturated and trans fats.
Eating plenty of vegetables, fruits, and whole grain foods.
Avoiding or limiting alcohol and caffeine.
Exercising regularly and managing weight.
Controlling heart disease risk factors, including diabetes, high cholesterol, and high blood pressure.
Coping and Support
An enlarged heart diagnosis can feel alarming, but the condition is manageable when the underlying cause is treated. Support strategies include keeping all follow-up appointments, taking medications exactly as prescribed, asking family members to help watch for warning signs such as new swelling or breathlessness, and joining a cardiac rehabilitation or heart disease support program where available [1] [2].
Preparing for the Appointment
If you think you may have an enlarged heart or are worried about heart disease risk because of family history, make an appointment with a healthcare provider. You may be referred to a cardiologist, a doctor trained in heart diseases [2].
Before the appointment, be aware of any pre-appointment restrictions such as diet changes or fasting before tests, write down all symptoms (including ones that seem unrelated), note key personal information such as family history of heart disease, stroke, high blood pressure, or diabetes, list all medications and supplements with doses, take a family member or friend along, and write down questions [2].
Useful questions include: What is likely causing my symptoms? What tests do I need? What's the best treatment? What foods should I eat or avoid? What's an appropriate level of physical activity? Are there restrictions I should follow? How often should I be screened for heart disease? Should my children be screened for this condition? [2]
The provider will likely ask when symptoms began, whether they come and go, how severe they are, what improves or worsens them, about diet, alcohol, smoking, exercise habits, other health conditions, and family history of heart disease [2].
Conclusion and Next Steps
An enlarged heart is a warning sign, not a disease. Something, whether a weakened muscle, a leaky valve, high blood pressure, or another condition, is making the heart work harder than it should, and the heart responds by growing. The good news is that the cause can usually be found and treated. Medications ease the heart's workload, devices keep the rhythm steady, surgery fixes valves and arteries, and a transplant stands ready as the final option.
Take action. If you have shortness of breath when lying flat, swelling in your legs, or an irregular heartbeat, contact a healthcare provider about a heart check. If chest pain, upper body discomfort, severe breathlessness, or fainting strike, call 911 immediately. Protect your heart with a low-salt diet, regular exercise, blood pressure control, and no smoking.
Frequently Asked Questions
Is an enlarged heart a disease? No. An enlarged heart (cardiomegaly) is a sign of another condition, not a disease itself. The term describes a heart that appears larger on an imaging test such as a chest X-ray, and further testing is needed to find the cause [1].
Can an enlarged heart go back to normal? It depends on the cause. When the enlargement comes from short-term stress on the body, such as pregnancy, or from extra fat around the heart, it may be temporary. Enlargement from heart disease may be permanent, but treating the cause can stop it from worsening [1].
Is an athlete's enlarged heart dangerous? Usually not. In some athletes, the heart enlarges in response to frequent, prolonged aerobic exercise. This type is typically not considered a disease and does not need treatment [1].
Can an enlarged heart cause sudden death? Yes. An enlarged heart may cause the heart to beat too fast or too slow, and the resulting irregular heartbeat can lead to fainting, cardiac arrest, or sudden death. That is why monitoring and treatment matter [1].
Is heart transplant the only option for an enlarged heart? No. Heart transplant is the final option, used only when the condition cannot be treated any other way. Most people are treated with medications, and devices such as pacemakers, ICDs, or LVADs, and with valve repair or bypass surgery [2].
Related Reading on Rinnit
Chest X-Ray (CXR): What It Shows, How It's Done and What Results Mean explains how a chest X-ray can reveal an enlarged heart.
Trusted External Resources
American Heart Association: What is Heart Failure?
American Heart Association: Warning Signs of a Heart Attack
American Heart Association: Lifestyle Changes for Heart Failure
National Heart, Lung, and Blood Institute: Cardiomyopathy
References
American Heart Association. What is Heart Failure? American Heart Association. Last Reviewed May 20, 2025. https://www.heart.org/en/health-topics/heart-failure/what-is-heart-failure
Mayo Clinic Staff. Enlarged heart: Diagnosis and treatment. Mayo Clinic. May 4, 2022. https://www.mayoclinic.org/diseases-conditions/enlarged-heart/diagnosis-treatment/drc-20355442
National Heart, Lung, and Blood Institute. What Is Cardiomyopathy? NHLBI, NIH. Last updated December 6, 2024. https://www.nhlbi.nih.gov/health/cardiomyopathy
American Heart Association. Warning Signs of a Heart Attack. American Heart Association. Last Reviewed December 12, 2024. https://www.heart.org/en/health-topics/heart-attack/warning-signs-of-a-heart-attack
American Heart Association. Lifestyle Changes for Heart Failure. American Heart Association. Last Reviewed June 16, 2025. https://www.heart.org/en/health-topics/heart-failure/treatment-options-for-heart-failure/lifestyle-changes-for-heart-failure
Vaduganathan M, Docherty KF, Claggett BL, et al. SGLT-2 inhibitors in patients with heart failure: a comprehensive meta-analysis of five randomised controlled trials. Lancet. 2022;400(10354):757-767. PMID 36041474. https://doi.org/10.1016/S0140-6736(22)01429-5
Halliday BP, Wassall R, Lota AS, et al. Withdrawal of pharmacological treatment for heart failure in patients with recovered dilated cardiomyopathy (TRED-HF): an open-label, pilot, randomised trial. Lancet. 2019;393(10166):61-73. PMID 30429050. https://doi.org/10.1016/S0140-6736(18)32484-X
Hofmeyer M, Haas GJ, Jordan E, et al. Rare Variant Genetics and Dilated Cardiomyopathy Severity: The DCM Precision Medicine Study. Circulation. 2023;148(11):872-881. PMID 37641966. https://doi.org/10.1161/CIRCULATIONAHA.123.064847
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