Hi thanks for your question.
You are not clear in your question, what is the abnormality ? is it left axis deviation? Or left atrial enlargement, or any other abnormality. The commonest abnormality of left atrium is its enlargement. The common reason for left atrial enlargement is mitral valve ( left side heart valve) stenosis .There is nothing to worry ,consult a cardiologist
to determine what is abnormality and what is the cause of this abnormality. Depending upon the cause, abnormality can be managed.
Hope this answers your question