I am not a physician, but it seems like quite a jump to go from possible AF for only a 20 beat run to Sotolol! I think the whole report sounds pretty good too. You had few PVC's or supravent. beats. In the setting of a normal heart structure, even multifocal PVC's are benign. Are you seeing a cardiologist or just a family doctor? And echo might be in order or more prolonged monitoring like an event monitor, but I would personally not take any meds yet.
What kinds of symptoms are you having? I have had a couple of event monitors and he time it has shown probable AFib. As a matter of fact, just yesterday I had a period of about 10 minutes, twice, of my heart beating really fast and irregular. The last time I saw my cardio, after the even monitor that showed the latest "probably Afib" he still just kept me on my ToprolXL. Mine report said Non-sustained possbile AFib - which led me to believe that it resolves on it's own - with both times it did yesterday - but it is scarier than heck. I also have Pacs and PVC's and have had for over 30 years.
I think that with Solatol, you have to be monitored in a hospital for three days when you start taking it, because it can cause irregular heart beats. You might want to google it. Frankly, I don't think your report sounds that bad.