I hope you can find a resolution. I too, have episodes of very low heart rate: down to 30, which is as low as Apple Watch will measure. Have had as many as 20 ‘low heart rate notifications’ per night but can’t get any helpful feedback from my cardiologist regarding cause. I initially fainted, which caused the focus on bradycardia as a possible cause. Other than the initial syncope episode, I have no symptoms when my heart rate is extremely low. I have done all the usual tests and even had a Medtronic Loop heart monitor implanted in my chest but have received no useful information from it.
I have bradycardia episodes for months at a time and then go several months without extra low bradycardia. Then, repeat the pattern. What are some causes that others have been told by their care team? Thanks.