Nancy - I was a mixed afibber… but tended to be mostly vagal…however on occasion, I’d have a late afternoon event. I learned eventually that it related to two things… hypoglycemia from running out of fuel during a grueling work schedule…and not enough sustaining food at lunch to carry through to the evening meal at 6 – 7. I worked by appointments and often there was no time to grab a snack. The race against the clock hour after hour was another contributor to stress. Eventually, this resolved by meal and snack management and retiring much earlier than intended. This did not, however, prevent the events during sleep…only the optimizing of electrolytes (Essential Trio) did that and I used at least 3,000 mg taurine daily.... and watching the potassium-to-sodium ratio.
If you aren't supplementing with taurine, you might give it consideration. Taurine is useful for those in sympathetic tone.
See the post on Taurine that I just added...review of past info.
Jackie