Why can’t I have both atrial fibrillation history and irregular rhythm notifications enabled? I am sometimes asymptomatic, but I take an anticoagulant as needed for atrial fibrillation events

No one here on this user to user only forum works for Apple. As such, we can't answer why questions as we didn't design the health features on Apple Watch. You came here from an Apple Support article, which explains what you can track. If you feel something is missed, feel free to share your thoughts with Apple here --> Feedback - Watch - Apple