A recent electrocardiogram revealed an enlarged left atrium. i'm only 25 but heart disease runs in my family. how serious of a condition is this?

Something to watch: Left atrial enlargement may be associated with some risk for future cardiovascular problems including atrial fibrillation (a rhythm problem) and possibly stroke. It also may suggest diastolic dysfunction (strain of the heart at rest). But all of these are conditions associated with aging and the risk of atrial enlargement found in young life may be different. Find a good cardiologist to work with!

Depends: There are 2 question: is the atrium truly enlarged and, if so, is there a reason for it: both can be answered with an echocardiogram. Usual reasons for left atrial enlargement are: hypertension, left ventricular diastolic dysfunction, atrial fibrillation, mitral valve disease, and atrial septal defect. The EKG is very indirect. The echo is much more accurate as it directly measures LA size.