Hello and welcome to HCM
I don't understand why you refuses to take beta blockers. According to your history you have given your are suffering from either Atrial fibrillation
. These are caused due to problem in the conduction system of the heart. The only non surgical treatment
for these are to take beta blockers or Calcium channel blockers. As you don't like beta blockers you can try calcium channel blocker like verapmil.
The other method to stop these episodes are to get a surgery done in which the part which is causing this fast heart rate
is partially burned by a device. But this is a little bit complicated procedure because all surgical procedure has its own complications.
My personal advice is to take medication and get rid from your problem. No other method can help you out. Hope you understand and start medication as soon as possible.