My personal experience is over 5 years old. But for most of us who had the procedure around then reported an echo or stress echo prior to the procedure.
CT is less used nowadays with the use of ICE (intracardiac ultrasound/echo) catheters during procedures. It helps to have the info and adds to the margin of safety especially if your EP wants to eliminate any structural surprises during the procedure. It can also be used as a reference map for catheter mapping during the procedure. So he is being extra cautious. What kind of ablation procedure are you getting? The complex it is, the more helpful it would be to have either CT or MRI scans prior.