Though there are a number of conditions, both congenital and acquired, which cause left atrial enlargement (LAE), a study by the American College of Cardiology found that the two most statistically significant causes are obesity and high blood pressure. Because it is considered a predictor of cardiovascular mortality, managing preventable causes of LAE is important.
Clinically speaking, left atrial enlargement (LAE) simply refers to a situation when the left atrium of the heart is larger or more dilated than normal. It is one form of cardiomegaly or enlarged heart which may, over time, lead to congestive heart failure and cardiac arrhythmias.
The causes of LAE are split between congenital predisposition for enlarged heart and environmental or lifestyle factors; only the latter are preventable. Among congenital causes of LAE, ventricular septal defects (VSDs), or a hole in the muscle wall between the heart's two ventricles, is especially prone to causing LAE.
A 2009 study by the American College of Cardiology specifically addressed the most common environmental causes of LAE in the general population. Its conclusion was that both obesity and high blood pressure are significant risk factors, but that obesity is the most important. Thus, according to the study, careful weight management, particularly among young obese people, is important to prevent premature cardiac remodeling (enlargement) at the atrial level.