A tech journalist who was diagnosed with afib after taking part in the Apple Watch heart study reported that he had undergone traditional EKGs more than once without a problem being detected.
>It's not the kind of thing that comes up in an EKG unless it is actually happening when the test is occurring. I've had EKGs a number of times, and there was never any indication anything was wrong.
I've even had heart tests as a precondition for having bariatric surgery four years ago, and been under general anesthesia, with no adverse results of any kind.
https://www.zdnet.com/article/how-apple-watch-saved-my-life/