What is Left Atrial Enlargement?
The left atrium is a part of the heart that plays an essential role in collecting blood and regulating how much blood enters the left ventricle, which is another part of the heart. The left atrium helps with these tasks during both systole and diastole; systole refers to when your heart contracts to pump blood out, and diastole is when your heart relaxes to fill with blood.
Left atrial enlargement (LAE) is a change in the structure of this part of the heart that happens due to consistent pressure and a significant amount of blood flow. This condition most commonly occurs alongside other heart-related issues such as diastolic dysfunction (a condition where the heart doesn’t fill with blood properly), left ventricular hypertrophy (an enlargement and thickening of the walls of your heart’s main pumping chamber), issues with the mitral valve (one of the heart’s four valves), and high blood pressure.
The size of the left atrium plays a crucial role in predicting health outcomes. Studies have shown that an enlarged left atrium can independently foretell the potential development of critical heart diseases and heart failure. In the absence of mitral valve diseases, irregular heart rhythms (atrial fibrillation), and high-flow heart conditions, an enlarged left atrium is a great indicator of left ventricular diastolic dysfunction. So, evaluating the condition of left atrial enlargement is important. This can be done using several types of medical imaging techniques.
What Causes Left Atrial Enlargement?
There are many reasons, both due to conditions a person is born with and those they get later in life, that can lead to a larger than normal left side of the heart (LAE). Here are some causes of that:
* Left ventricular diastolic dysfunction is when the lower left chamber of the heart does not relax as it should between heartbeats.
* A left to right shunt is when there’s an abnormal flow of blood from the left side of the heart to the right. This can happen because of a hole in the wall between the heart’s chambers, called a ventricular septal defect (VSD), or because of an open blood vessel that usually closes after a baby is born, called patent ductus arteriosus (PDA).
* High blood pressure, or hypertension, makes the heart work harder to pump blood.
* Aortic stenosis is a condition where the heart’s main outlet, the aorta, is narrower than usual.
* Mitral stenosis is a condition where one of the heart’s valves, the mitral valve, is narrower than usual.
* Mitral regurgitation is a condition where the mitral valve doesn’t close as tightly as it should, causing blood to flow backwards into the heart.
* Left ventricular failure means that the lower left chamber of the heart isn’t pumping blood well enough.
* A left atrial mass or myxoma is when there’s an unusual growth in the left side of the heart.
* Arteriovenous fistulas are abnormal passages between arteries and veins.
* Athlete’s heart is a term for changes in the heart’s size or function due to regular, intense exercise.
Risk Factors and Frequency for Left Atrial Enlargement
It’s hard to say exactly how common left atrial enlargement (LAE) is. Yet, according to a study by Bombelli and co-researchers, out of the participants observed over a 10-year period, 12% developed LAE. At the start of the study, the average age of the participants was 47. Certain physical factors, such as age, gender, and body size, can affect the size of the left atrium. LAE isn’t a normal part of aging but instead, comes about from certain changes tied to the aging process. Also, men have larger left atria than women, and a person’s left atrium size tends to grow as their body size increases.
Signs and Symptoms of Left Atrial Enlargement
Left atrial enlargement (LAE) doesn’t have its own symptoms. Instead, it’s a response to other heart-related conditions. So, it’s essential to pay attention to the symptoms tied to these underlying causes of LAE. Some people with LAE may experience a variety of symptoms such as:
- Feeling the heart pound or race (palpitations)
- Shortness of breath (dyspnea)
- Fainting (syncope)
- Swelling in the arms and legs (peripheral edema)
- Tiredness (fatigue)
- Weight gain
On the other hand, some people in the early stages of heart diseases like left ventricular hypertrophy (an enlarged left pumping chamber of the heart), mild mitral valve diseases (issues with the heart’s mitral valve), or undiagnosed high blood pressure may not show any symptoms. In such cases, the first signs might appear in heart tests like an electrocardiogram or echocardiogram conducted for other reasons. That’s why it’s necessary to properly evaluate the patient’s current and past health history, social and family history. This includes investigating any risk factors for left ventricular hypertrophy, valve abnormalities, congenital heart diseases, irregular heart rhythm (arrhythmias), and high blood pressure.
Testing for Left Atrial Enlargement
Different methods can be used to measure your left atria (LA) with an echocardiogram. However, just measuring the length of the LA might not give a true picture of the size, especially if the LA is larger in some areas than in others. Therefore, doctors now measure the volume of the LA. Recommendations to measure the LA’s volume usually involve using the two-plane area-length method or the Simpson’s two-plane method. The volume of your LA can be impacted by your body size, so it’s typically adjusted based on your body surface area. A standard LA volume is considered to be 22 ± 6 milliliters/meter squared. If the volume is larger than 28 milliliters/meter squared, the LA is considered enlarged.
Three-dimensional echocardiography is increasingly being used to better examine the LA volume and enlargement.
An electrocardiogram (EKG), another way to measure the heart’s function, can help identify if the left atrium is enlarged. If specific features are detected on an EKG, it would suggest the need for further investigation. These signs include: the P wave (a portion of the heartbeat) in any lead longer than 0.11 seconds, a notched P wave with an interpeak duration exceeding 0.04 seconds (known as P mitral), or the angle of the P wave less than 30 degrees. If any of these signs show up on an EKG, the doctor might look into the possibility of LA enlargement.
Treatment Options for Left Atrial Enlargement
There are no established treatment guidelines specifically for Left Atrial Enlargement (LAE), a condition which marks the increase in size of the heart’s left atrium chamber. At present, there’s no medicine that can reverse the changes in the heart caused by this enlargement. Instead, medical care focuses on identifying and treating any underlying health problems that may have led to LAE.
For instance, people with valve abnormalities like mitral valve stenosis (narrowing of the heart’s mitral valve) or regurgitation (leakage of blood backward through the mitral valve each time the left ventricle contracts) may receive treatments aimed at relieving their symptoms. They might also undergo procedures to repair or replace the problematic valve. If these patients also develop irregular heart beats, or arrhythmias, they might need anticoagulation therapy—a medication regimen designed to prevent the formation of blood clots.
High blood pressure, which is a widespread risk factor for heart and blood vessel diseases, can be addressed with a variety of blood pressure-lowering medications. Lifestyle changes can also help manage hypertension. These can include adopting a low-salt diet, being physically active, limiting alcohol intake, and quitting smoking.
In cases where left ventricular dysfunction or heart failure (conditions affecting the heart’s ability to pump blood) are present along with LAE, medicines remain the main treatment option. Medications known as beta-blockers, angiotensin-converting enzyme inhibitors, and mineralocorticoid receptor antagonists are typically used. A newer medication called sacubitril/valsartan, which inhibits a substance known as neprilysin, is also emerging as a beneficial treatment for patients with a certain type of heart failure where the heart muscle doesn’t contract as well as it should.
What to expect with Left Atrial Enlargement
Left Atrial Enlargement (LAE) is a serious health issue that should not be taken lightly. The size of the left atrium, one of the four chambers of your heart, can predict the risk of deadly and non-deadly heart-related events. It’s important to note that this risk exists even when there are no signs of Left Ventricular Hypertrophy (LVH) – a condition where the muscle wall of the heart’s left pump (ventricle) becomes thickened (hypertrophy). This risk prediction is over and above other known heart-related risk factors such as high blood pressure.
The size of the left atrium is also independently linked to the risk of death from any cause in both men and women. More so, in women, it has an independent connection to the occurrence of ischemic stroke – a type of stroke that happens when the flow of blood to the brain is blocked.
All these point to the crucial fact that if any factors causing LAE are found, they should be appropriately treated. This approach will help avoid potential severe health outcomes and prevent a decline in the quality of life.
Possible Complications When Diagnosed with Left Atrial Enlargement
The most frequent problems that are experienced include:
- Atrial fibrillation, an irregular heart rhythm
- Stroke, where blood flow to a part of the brain is cut off
- Heart failure with preserved ejection fraction (HFpEF), a type of heart failure where the heart muscle contracts normally but is too stiff to relax as it should
Preventing Left Atrial Enlargement
Patients with an enlarged left chamber of the heart, or ‘left atrial enlargement’ (LAE), may not show any symptoms throughout their lifetime. Even so, LAE could be an indication of other existing heart issues that need further investigation. As the condition itself cannot be directly treated, it’s essential that patients with an enlarged left chamber of the heart are educated about their possible hidden heart issues. They should receive proper guidance on managing these conditions, which could vary from making simple changes to their lifestyle to considering surgical evaluation and treatment.
