Watches and the two-finger device that is being sold on TV obviously can't match the 12 lead EKGs done at doctor's offices or hospitals. They shouldn't be perceived as diagnostic. The Oura Ring (I'd really like to have one) is more intimately connected to the body than a watch and might provide a better EKG - but it's still using one lead.Being an ex-CCU nurse and able to read rhythm strips well, I completely agree with Eva and vitdoc.
If you believe your cardio to be competent, ask for a Holter monitor. Ask him to explain what he doesn't see as an issue, but you feel is a big issue. It may be that explaining some benign minor arrhythmia and why it is benign and what it looks like, etc., etc., may be too in-depth and too time consuming for him.
Ask questions. Get a Holter, get a repeat EKG or a copy of your EKG. Make an appointment to discuss these reports with him and say you want to understand in a very rudimentary way why he is not concerned, not that you want to become an expert in reading arrhythmias.
A strong opinion on this forum regarding rhythm strips via wrist watches is that they are not accurate compared to technology performed in hospital.
However, even with the one lead EKG, these things can do readings that may suggest cardiac issues. (The $79 device will spot bradycardia and A-Fib - big deal - they're just counting heart rate.) I've seen a device that lets you send the results of the EKG to a 'medical professional' for interpretation - probably at a significant fee.
No. I don't trust my watch to give me a professional quality EKG, but it may help to separate 'Inconclusive' from 'sinus rhythm.'
One other device that does a bit of diagnosing - recent blood pressure machines. The ones I use have an indicator on the screen that shows that an arrhythmia was found (this is why it can't get an accurate heart rate). It doesn't define what kind of arrhythmia, but IS an indication that you're not having normal sinus rhythm while it's testing your BP.