Overview of Left Atrial Enlargement

The left atrium is located in the upper left part of the heart. It is one of four chambers in the heart. Too much pressure or too much blood volume can both cause the left atrium to become bigger, which causes left atrial enlargement (LAE). The increased pressure or volume is caused by an underlying cardiovascular condition—discovering that someone has LAE should initiate the search for the condition that is causing it.

Sometimes, an enlarged atrium does not cause any symptoms. The occurrence of symptoms depends on the extent of the enlargement in the left atrium. If the increase in size is substantial, symptoms are likely to be experienced. If symptoms are noticed, they may include:

• Chest pain
• Breathing problems, including shortness of breath and coughing
• Extreme fatigue
• Abnormal heartbeat
• Fluid buildup and swelling
• Fainting

But the symptoms above are also characteristic of numerous conditions affecting the heart, including congestive heart failure.

Another symptom that can be caused by LAE is dysphagia, or difficulty swallowing, is due to the impingement of a massively enlarged atrium on the esophagus.

Symptoms of underlying health conditions tend to bring about reason for concern and enlargement may be advanced before the condition is realized. Often, however, the condition is only discovered during testing for other conditions, especially cardiovascular diseases.

Health conditions most commonly associated with the enlargement of the left atrium include high blood pressure, atrial fibrillation, mitral valve dysfunction, and left ventricle problems. These conditions can produce elevated left atrial pressures, elevated left atrial volume, or both—leading to LAE.

While left atrial size is influenced by aging, sex, and body size, these are not causes or risk factors for LAE. Underlying cardiovascular diseases can cause LAE no matter your age, sex, or body size.

High blood pressure is common in people with LAE. One review in the American Journal of Hypertension of 15 studies over a period of 12 years found that LAE was present in 16 to 83% of people with high blood pressure. In people with high blood pressure, LAE is often related to asymptomatic diastolic dysfunction.

Atrial fibrillation (A-Fib) is a problem that causes arrhythmia, or irregular heartbeats. This causes the two upper chambers of the heart to beat differently than the two lower chambers. Persistent A-Fib may eventually enlarge the left atrium. A-Fib can either be permanent, persistent, or paroxysmal, and newer research confirms LAE is both a cause and a complication of A-Fib. 

An analysis of a large study reported by the British Cardiovascular Society looked at risk factors for heart disease. The data looked at various heart conditions, including A-Fib. The researchers looked at the size of study participants' left atriums. What they found was that enlarged atriums were common in people with A-Fib. Based on the results, people with enlarged left atriums were 60% more likely to develop A-Fib and those with a severely enlarged atrium were four times more likely to develop A-Fib than people with normal heart chambers. The researchers confirm that an enlarged left atrium is an independent risk factor for A-Fib, much like strokes and heart failure. A second 2018 study has confirmed these findings, adding that an enlarged left atrium is a predictor of A-Fib.

Research reported in the International Journal of Cardiology finds evidence that LAE may also be a consequence of A-Fib. In this study, researchers were able to determine left atrium changes were common in people with A-Fib and occurred in a slow and progressive manner.

Some conditions associated with the mitral valve may contribute to LAE. The mitral valve is the heart valve that lies between the left atrium and the left ventricle. Mitral stenosis causes the mitral valve to narrow and makes it harder for the left ventricle to be filled. 

Mitral regurgitation, on the other hand, causes blood to leak from the left ventricle into the left atrium. Both of these conditions make it difficult for the left atrium to pump blood to the left ventricle, resulting in increased pressure in the left atrium—this eventually causes enlargement. 

The connection between mitral valve problems and LAE is common. One 2013 study finds that when LAE is asymptomatic (without symptoms) mitral valve replacement can decrease the size of the left atrium and potentially reduce any specific symptoms to LAE.

Problems with the left ventricle put pressure on the left atrium, leading to the enlargement of the left atrium. Left ventricle and left atrium problems seem to go hand-in-hand. For example, one 2019 study reported in the Journal of the American Society of Hypertension finds that people with left ventricular hypertrophy (LVH) have higher systolic blood pressures (SBPs) and larger left atriums. 

SVH is a condition where the muscle wall of the heart left chamber, the ventricle, becomes thickened. The SBP is the number on top in a blood pressure reading that indicates the amount of pressure that blood exerts on the vessels while the heart is beating.  

A diagnosis of LAE can be made by looking at the heart with an echocardiogram. This test uses ultrasound to take pictures of the heart. 

The test is performed with the person lying down on a table and the technician attaching metal electrodes to the person’s chest. The technician will then pass a small sound wave probe over the chest. These sound waves bounce off the heart and echo back to the probe, producing images. The echocardiogram is a safe procedure that causes no pain or harm and has no side effects. 

Other tests that may be used in the diagnosis of LAE include magnetic resonance imaging (MRI) and computed tomography (CT) scans. These tests make measures of the left atrium to determine its size and if it is enlarged in comparison to its normal size.

Treatment of left atrial enlargement focuses on identifying and treating the cause of it. 

High blood pressure is treated with medications and management of unhealthy habits, including a healthy diet low in salt. It also involves limiting alcohol, exercising, managing stress, and not smoking.  

Treatment options for mitral stenosis include diuretics to reduce fluid, blood thinners to prevent clots, and anti-arrhythmic drugs to manage irregular heartbeat. Additionally, surgery can repair or replace the mitral valve.

Treatment for mitral regurgitation includes medications to reduce the risk of blood clots. Much like mitral stenosis, surgery can repair the problem.

Most people with left atrial enlargement have no symptoms. Having LAE is generally a sign of an underlying heart condition. Treatment for conditions associated with LAE vary from lifestyle changes to medication and surgery.  LAE can also put people at risk for additional heart problems, so it's important to keep blood pressure and heart rhythms under control. If you have a family history of heart problems, be sure to tell your doctor. This way, your heart health can be carefully watched.