A grey graphic of a human heart.
An enlarged heart is not a disease itself, but it is caused by an underlying health condition.

What Causes an Enlarged Heart?

Many of us are familiar with the children’s tale where the central character’s heart grew several sizes in a day. In reality, your heart cannot grow so much over such a small period of time, however, some health conditions can lead to an enlarged heart. So, what causes an enlarged heart?

What Is an Enlarged Heart?

An enlarged heart is not a disease in its own right; it is actually a symptom of another health problem that causes the heart to work overtime. The professional term for an enlarged heart is cardiomegaly. When another health condition affects the heart, the heart can increase in size because of increased demand on this muscle. A normal heart is about the size of a clenched fist, but some health issues can thicken the heart wall muscle or stretch the heart chambers, giving an affected heart a larger size.

The Heart Enlarges in Two Ways

In cardiomegaly, there are two ways your heart becomes enlarged:


The muscle in the heart walls stretch out, weakening the muscle and making the muscle wall too thin. When heart muscle dilates to create an enlarged heart, it can lead to heart failure because the heart’s ability to pump properly is compromised.


This has the opposite effect of dilation. Instead of stretching thinner, the heart walls thicken and reduce the heart’s efficiency.

Pathological vs Physiological Cardiomegaly

An enlarged heart happens because of pathological reasons or physiological reasons. Pathological causes are when the enlarged heart forms because of an actual disease of the heart muscle. A physiological cause of an enlarged heart is the result of other health issues that reap havoc on the heart and cause it to work harder. An example of a physiological cause would be high blood pressure.

Causes of an Enlarged Heart

An enlarged heart could be a symptom of several health factors—even a short-term stress on the body:

  • High blood pressure/pulmonary hypertension
  • Coronary artery disease
  • Heart valve disease
  • Cardiomyopathy
  • Heart attack or history of a previous heart attack
  • Infections of the heart
  • Anemia
  • Fluid around the heart
  • HIV infection
  • Thyroid disorders
  • Kidney diseases
  • Genetic or inherited conditions
  • Old age
  • Pregnancy

How Is an Enlarged Heart Diagnosed?

Doctors usually start with a physical exam and discuss your symptoms with you. They’ll use your medical history and family history and send you for testing. Depending on the information the doctor gets from your history and physical exam, they may send you for a chest x-ray, echocardiogram, electrocardiogram, MRI, blood tests and an exercise stress test. In some cases, you may be sent for a doppler study, which is another test that shows how blood flows through the heart valves and allows the doctor to determine if the valves are functioning normally.

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Risk Factors

You’re at risk for an enlarged heart if you have a condition that stresses out your heart. There are a few groups that have an increased risk:

  • Older folks: Your heart muscles have had more time to wear down and lose elasticity and you are also more vulnerable to other conditions which may affect your heart.
  • Those with high blood pressure: Your risk goes up if your blood pressure is higher than 140/90 millimeters of mercury.
  • Family history: If an immediate family member has an enlarged heart, your risk increases.
  • Sedentary lifestyle: Folks in this category are at increased risk of several types of heart disease.
  • Congenital heart disease: Conditions that affect the heart’s structure add additional strain to the heart.
  • Heart valve disease: Damage to your heart’s valves may cause the heart to enlarge.

What Are the Symptoms?

You may be unaware that you have an enlarged heart until the condition becomes more severe. Symptoms may not be noticeable in the early stages because they may present subtly:

  • Chest pain
  • Shortness of breath or other breathing problems
  • Heart palpitations (a rapid or pounding heartbeat)
  • Arrhythmia (an irregular heartbeat)
  • Dizziness or fainting
  • Rapid exhaustion with physical activity
  • Swelling or fluid retention

Understanding the Complications

In some cases, an enlarged heart becomes a very serious concern. If there are any issues in your chest or heart, see a doctor as soon as possible. An enlarged heart can lead to devastating conditions, including heart failure, blood clots, a heart murmur, cardiac arrest and sudden death.

How Doctors Treat Enlarged Hearts

Many cases are treatable by finding and correcting the cause of the enlarged heart. By resolving the causal health issue, doctors can control the symptoms of an enlarged heart and prevent additional complications or damage. Treatment depends on the diagnosis and how much your heart has been enlarged. Some treatments that doctors prescribe (depending on the diagnosis):

  • Medications to address the underlying problems such as diuretics, ACE inhibitors, beta-blockers, antiarrhythmics, other blood pressure medications, and more. There are also medications available to help the heart from enlarging further.
  • Reducing blood cholesterol levels by changing to a heart-healthy diet that is low in fat. Some diets have been proven to reduce the risk of heart disease—see a nutritionist or doctor if you are unsure of what you should or should not consume.
  • In some cases, heart surgery may be required. These surgeries may include heart valve surgery, coronary artery bypass surgery, heart transplant, implantable cardioverter defibrillator (ICD), left ventricular assist device (mechanical pump for heart failure patients), and more.
  • Lifestyle changes make a lot of difference in your heart health. Make sure to control your blood pressure, diabetes and blood cholesterol. Exercise more, maintain a healthy weight, get your stress under control, drink less alcohol and give up smoking.

Your heart is your life force. Once you have found the cause of an enlarged heart, keep checking in with your doctor to make sure that your treatments are working.

Keep your big heart metaphorically, but not literally.