A good sign. Your primary care, surgeon and anesthesiologist are being careful. Checking the right pre op tests. Gallbladder surgery is seldom urgent let them do a thorough evaluation of the ekg abnormality. If there are real cardiac issues, that should be addressed prior to an elective surgery. If the cardiac tests come out ok, you can have a safe operation.
Precautionary. Its routine to get a pre op ekg to make sure you will be able to tolerate anesthesia. Most likely you will see a cardiologist to evaluate your heart prior to undergoing the galllbladder operation.