By Rachael Zimlich, BSN, RN 

Updated on May 17, 2023

 Medically reviewed by Jeffrey S. Lander, MD

Right atrial enlargement occurs when the right atrium, one of the heart's upper chambers, is larger than normal. The right atrium is the first entry point of blood returning to the heart from circulating in the body. This enlargement can increase the amount of blood and pressure of blood flow leading into the right ventricle and eventually the pulmonary artery in the lungs.

While left atrial enlargement can cause chest pain and breathing problems, alerting you to the dangerous condition, right atrial enlargement usually develops with no symptoms at all.

This article covers the signs and complications of right atrial enlargement. It also discusses the causes, diagnosis, and treatment.

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Types of Right Atrial Enlargement

Right atrial enlargement goes by several names, including right atrial hypertrophy, overgrowth, or dilation. There are nuances among the diagnoses, but the outcome of each is the same—the right atrium of the heart is larger than normal. This means that the right atrium can hold more blood than it should until that larger volume of blood passes to the next, average-sized heart chamber.

There are several types of cardiomegaly, or heart enlargement. Enlargement can affect the entire heart or specific chambers, and you can be born with the condition or develop it from chronic conditions like high blood pressure.

How Big Is Too Big?

A normal right atrium can hold between 11 and 40 milliliters (ml) of blood at a time.¹ In people with atrial enlargement, the atrium can hold far more. There have been rare cases in which the right atrium can hold 700 ml² and even 1,900 ml.³

Different types of right atrial enlargement are classified by how or when the problem develops. Idiopathic enlargement of the right atrium (IERA) is a rare condition that can exist with or without other heart problems.⁴

Right atrial enlargement can also develop over time due to a number of other heart problems or conditions, such as high blood pressure or heart valve disorders.

Symptoms

In many cases, people with right atrial enlargement have no symptoms at all and may never even know that they have it. In fact, one study estimated that 48% of people with congenital (present at birth) or idiopathic (arising spontaneously) right atrial enlargement have no symptoms.⁵ It is usually diagnosed by accident or when a complication results.

Symptoms occur more often in people who develop complications from right atrial enlargement or whose condition arose from other cardiac problems. Possible symptoms include:⁶

• Arrhythmia (abnormal heart rhythm)

• Chest pain

• Shortness of breath

• Palpitations (heart racing or pounding)

• Edema (swelling), especially in the legs

• Fatigue

When Is Discomfort an Emergency?

If you have any of the following symptoms—especially if they come on quickly and strongly—call your doctor, 911, or visit an emergency department immediately:

• Chest pain that continues after rest or medication

• Shortness of breath, even at rest

• Dizziness

• Coughing up pink phlegm or blood

• Loss of consciousness

• Unresponsiveness

Causes

Some possible causes or conditions related to right atrial enlargement include:

• Atrial fibrillation: An irregular heart rhythm caused by abnormal electrical impulses in the heart

• Congestive heart failure: A decrease in the heart's ability to pump blood effectively

• Chronic obstructive pulmonary disease (COPD): A chronic respiratory condition that can cause strain on heart function

• Pulmonary hypertension: Increased pressure in the pulmonary artery that can lead to heart failure

• Pulmonary stenosis: A narrowing or restriction of the pulmonary artery

• Tetralogy of Fallot: A congenital heart defect with specific abnormalities in the anatomy of the heart

• Tricuspid stenosis or regurgitation: Failure or weakness in the tricuspid valve that can cause blood to leak back into the right atrium from the right ventricle

• Pulmonary atresia: A congenital defect that occurs when the valve that helps blood flow from the heart to the pulmonary artery doesn't form correctly or at all⁷

• Septal defects: Tiny holes that develop when the heart is forming

• Heart valve disorders: Problems with the different valves in the heart that control the flow of blood

Why Atrial Enlargement Doesn't Occur Alone

When atrial enlargement develops over time, it usually indicates severe heart problems. In many cases, there is a domino effect of one problem leading to another. For example, valve disorders like tricuspid regurgitation can cause pressure imbalances, resulting in conditions like pulmonary hypertension. In time, pulmonary hypertension can lead to atrial enlargement or more severe cardiomegaly and heart failure.

Diagnosis

The first step your doctor will take is to complete a physical assessment and ask you about your family and personal medical history. Your doctor will also perform a physical exam and listen to your heart and lungs. You may even have blood work done to check your overall health and wellness.

If these exams or tests raise any red flags, your doctor will move on to heart-specific testing to get more information about how well your heart is functioning. One of the tools your healthcare provider will use is an electrocardiogram (ECG or EKG). It measures the electrical signals of your heart and how well its electrical and pumping systems are working. However, it's usually more accurate for diagnosing left atrial enlargement than right atrial enlargement.⁸

An ECG will provide a lot of information to your doctor, but even if a problem is detected on the ECG, there are many things that could be to blame. If your healthcare provider suspects you have right atrial enlargement or is trying to diagnose other heart conditions, a number of tests may be ordered, including:

• Transesophageal or transthoracic echocardiography, which allows your doctor to look at your heart

• Electrophysiological testing, which evaluates your heart's electrical system and checks for abnormal heart rhythms

• Cardiac magnetic resonance imaging (MRI)

• Multiple gated acquisition scan (MUGA), which evaluates the pumping function of the ventricles

With some imaging tests, your doctor can see blood flowing in real time through the chambers of your heart. Pressures and sizes can also be measured.

Your doctor may also perform noncardiac tests like an X-ray to rule out other conditions that could be causing problems in the heart, such as respiratory diseases.

Why Atrial Enlargement Develops in Athletes

Atrial enlargement can develop in athletes as a result of intense endurance exercises. Heavy exercise can cause cardiac remodeling, which is a group of changes in heart tissue due to the increase in blood volume that occurs during activity. Long periods of increased volume can cause enlargement of the heart—mostly in the left atrium, but it can also happen in the right atrium.

Treatment

There is no real consensus on the best treatment for right atrial enlargement. Surgery may be done in severe cases, or even early on to prevent further problems from developing.

Surgical options may include open-heart surgery for resection (removing excess tissue) or ablation. Ablation is a procedure that scars heart tissue. It is often used to correct abnormal heart signals that can cause acute or even fatal events like stroke or heart attack.⁹

Other, more conservative treatment options include:¹⁰

• Watchful waiting, or using regular follow-up visits to monitor the progression of your condition

• Taking medications like beta-blockers to improve the pumping function of the heart

• Taking anticoagulants to reduce the risk of clot formation in the atrium due to inadequate pumping

• Using implanted devices like pacemakers or defibrillators to control abnormal rhythms

• Taking medications to control your blood pressure or heart rate

How Long Does It Take to Recover from Open-Heart Surgery?

Open-heart surgery is major surgery. Even with less-invasive cardiac surgeries, you should prepare for a significant recovery and rehabilitation period. If you have open-heart surgery, you will spend time in an intensive-care unit with various drains and even a breathing tube for the immediate recovery period. Expect to spend up to two weeks in the hospital, followed by outpatient cardiac rehabilitation.

Prognosis

An enlarged heart can become ineffective at pumping blood to where it needs to go or have disturbances in its normal electrical impulses. Both of these can result in a change in heart rhythm, heart failure, stroke, and even death.¹¹

You cannot reverse an enlarged right atrium, but you may be able to treat the root cause if the enlargement is caused by something like high blood pressure or a bad valve. Surgery is an option for treatment, but your doctor may also choose to monitor you and treat your symptoms with medications.

Complications

A number of serious complications can occur with right atrial enlargement. Since about half of all known cases of right atrial enlargement have no symptoms, the condition can get worse over time without anyone knowing. Eventually, it can lead to more severe problems, such as:⁶

• Supraventricular tachycardia, an abnormally fast heartbeat beginning above the heart's two lower chambers

• Atrial fibrillation, an irregular, often rapid heart rate that commonly causes poor blood flow

• Atrial flutter, the heart's upper chambers beat too quickly

• Right-sided heart failure

• Pulmonary embolism, where one or more arteries in the lungs become blocked by a blood clot

• Heart attack or sudden cardiac death

 Weak Heart Symptoms and Treatments

Preventing Right Atrial Enlargement

You may be able to prevent right atrial enlargement by treating the heart and lung conditions that may cause it. This may include:

• Heart medications

• COPD medications

• Heart or lung surgeries

• Supplemental oxygen

Lifestyle factors may also be helpful for heart and lung health. This includes:¹²

• Quitting smoking

• Eating a healthy diet with plenty of produce and minimal processed foods

• Getting regular physical activity

Summary

Right atrial enlargement happens when the right atrium fills up with more blood than normal. It doesn't come with any symptoms, so by the time you realize something is wrong, it may have progressed and caused other complications already. However, there are many treatment options like medications and surgery that can help you manage this condition.