Hi! It looks like we may have some of the same conditions. I was also looking for the same thing — I did tons of research this past year. The main ones that I considered getting were the FitBit Versa 3. I liked that the screen showed the heart rate constantly. The next was the Garmin Venu bc it sends notifications when you have abnormal heart rates through alerts. I ultimately landed on just the classic Apple Watch series 8. I’ve had mine since December and am loving it. It was very pricey for me to buy but it was worth saving up for. Since I’ve had it, it has alerted me by vibrating & noise when my heart rate reached the alert threshold I set — for example I set mine at 150 so if my heart rate gets above that when I’m resting or unresponsive, it will alert me. Secondly, since I have fainting episodes from vasovagal syncope, I’ve set it to where it will immediately alert emergency services like 911 if I am unresponsive for a long period of time. It is truly awesome. I feel so much more at ease since I am able to see my heart rate all the time, have peace of mind if I pass out, and if I am going into afib etc. I would highly recommend! Good luck