watch readings

Hi there. I have been dealing with figuring out a case of long qtc for awhile now. A year ago multiple EKGs in the ER showed it elevated, but since then it's been controlled on 12 point leads - though Idon't believe anyone has ever hand calculated it.

I have an apple watch and the Qaly app. I just downloaded ECG+ and it's showing a huge difference from Qaly, and really high numbers. I went to the ER last night b/c I was so freaked out. They said it looked normal. I just did another read here at home and Qaly says 460 where as ECG+ says 608.

Does anyone have any experience with the reliability of these readings? I have calls into my doctor and they're like oh we'll see you in a few weeks, meanwhile I'm worried I'm going to drop dead. Appreciate any thoughts.