Hey FlexGate, I'm sure you will be fine. If the hospital said your fine then you should pass the ECG with no problems whatsoever.
I got really worried too during my class 2 medical as I have something called Dextrocardia which means my heart is on the right hand side of my body (pretty weird, yes I know) but I still passed my ECG (although they had to swap all the wires around haha) and I sent a letter from my cardiologist to the CAA and they were happy with it!
