I have a buddy who had similar heart issues, due to excessive cardio exercise, and also needed two ablations. He got his medical back fairly quickly, airline guy so 1C.
You'll definitely want a medical in hand before you spend money on training. If you're even thinking of maybe professional aviation get a a 1C, otherwise a 3C.
You can try using google or the forums to find a good AME in your area, and then reach out to him *before* you fill out the FAA form. Some AME's are just "box checkers" and won't be very helpful with complicated issues which get referred FAA aeromedical for analysis and adjudication.
Alternatively, contact a medical consulting service which specializes in helping with this sort of issue (there will be a fee). AMAS is one, and there are others.