I was diagnosed with AFIB about four years ago (paroxysmal) and prescribed Xarelto to ward off strokes. Definitely hereditary (along with other cardiac issues - such as "familial
hyperlipoproteinia . What a mouthful, don't know how I remembered it!). Diagnosed by the head of the Johns Hopkins lipid department some 15 years ago.

One brother died in his sleep two years ago only a week before having a second stent put in place, and the other takes beta blockers in addition to his Xarelto (his AFIB is constant rather than paroxysmal ) as do I, but only PRN .

I use not only the Apple Watch to keep informed about my arrhythmias but now also a Kardia device - a six stranded EKG monitor. (Note FWIW that the newer model Apple Watch same generous son purchased for me, also gives info on my oxygen levels during sleep. With it, I and can also check on it when I care to during the day). It even checks snoring!

The Apple Watch proved more useful than the pricy subscription fall detector he got for me (living alone, he feared I might fall without its being noticed) but it was just way too sensitive. The the police were at my house several times for false alarms. Another plus from it , is that it can even car accidents.
Not long ago, it detected a "crash" in a highway car accident and called the highway patrol by GPS. It wasn't actually a collision but a scary loss of steering control, which ended in a severe shock when I dropped down on the berm after I had (just by luck).
managed to escape from traffic and get off the road.

I was amazed at this capability I hadn't even known it had - it even records your trajectory before you stop from whatever cause. In this case, the sharp drop from the berm was what triggered the alarm (narrowly escaping falling down a cliff just a tad further to the right!).

I must sound like an ad for Apple, but it really has been a huge help to me though the extra apps are a bit finicky in recording both falls and the two extra paid apps (sleep and heart beat when awake, for instance, at the gym).