I think you need to understand the way the system works.
DoDMERB is basically the source that processes the medical exams. If the condition is considered disqualifying than it will go to the commissioning source for a waiver.
You stated various SAs. USMA may decide to waive the condition while USNA and USAFA decide not to waive. SAs and ROTC are considered different commissioning sources, and that means if applying for ROTC scholarships you will also have to go through their (ROTC) waiver process.
One thing to realize is standards. you mentioned you had an EKG with no problems, but no problems does not equate to military standards. IE this board is littered with candidates that have allergy issues, and for most people that would be no problem, but for the military it can become an issue.
You know you have this issue. Here is my suggestion, try to find a doc that has military background and have them do the EKG. If you can't than try to find a DoDMERB consultant so you can get in front of this.
Finally, pm KP2001 and see if they know whether this is a deal breaker.
JMPO, I would prepare for the worst, but move forward and apply to both the SAs and ROTC. Your heart may be ripped out for a few moments, but when you are 30/40/50 etc you will know that you tried and never wonder that what if? What if I didn't listen to posters and applied, even if there was 0.1 % chance I could have been that 0.1% chance. Don't live with any doubt or what if because that will haunt you much longer than the few months of licking your wounds because they decided your fate.
Good luck