If the abnomalities are borderline there is no need for immediate action and as the surgeon said, no problem for your upcoming surgery. I suggest that you have that surgery first.
After that, it might be a good idea to contact a cardiologist to get more info on the bradycardia and the LA enlargement.
-Note that a slow heart rate is often no problem and only needs treatment is symptoms from it become severe like fatigue, weakness, dizziness or fainting.
-LA enlargement is indicated from the EKG. A reliable measurement for LA can however not be derived from EKG.
To get a good idea of the size of the LA, an echo is the best way to measure its size and, if indeed enlarged, to check what might have caused it.