OP, what do you consider to be the downside to getting the EKG?
- Is he going to charge you more for an exam that includes the EKG? I'd be surprised, and even if so, I doubt it's more than a few gallons of avgas.
- Is he going to find something concerning? How is knowing/learning about a health condition a downside? "Ignorance is bliss," but sticking your head in the sand isn't good for you or those who care about you.
- Are you worried about being "denied" based on EKG results? You can't be "denied" a BM due to EKG (or any other) results the way a health issue can complicate a Class 1,2,3 issuance. A doc can refuse to do BasicMed, or refuse to complete the paperwork after examining you if they don't feel comfortable putting their name on the paperwork. If you really think they're just being foolish, then just spend a few more bucks and try your luck with a different doc. It's not like a Class 1,2,3 where there's a gov't record of your health issue that you have to explicitly deal with before you can hope for success.
Unless you're so strapped for cash that spending ~$50-100 requires extreme consideration, why even hesitate?