The cardiologist's office had said a couple days ago that the tests looked normal. (It's so nice to have something in my life that's a benchmark of normalcy and I think we can all agree that if anything was going to be normal in one's life, heart rhythm would be a really good thing to have as that benchmark!) He says that there's no reason for me to follow up with him and that just checking with my GP should be adequate.
In other words, this was a "lone" or "paroxysmal" atrial fibrillation officially. We don't know why it happened, but it did, and there is no lasting damage we can detect. I'm on increased beta blockers for this, but other than that, there's nothing to worry about.
Back to work for me, clearly. :)