Sounds like you have a history of responding well to medications for arrhythmia, so looking for a new one that works seems a good strategy. I don't know "ideral", has it been available for 40 years? If yes, there are many newer ones available, not sure newer is better, but worth a look.
I consider Metoprolol mainly a blood pressure and heart rate lowering drug, not particularly good for arrhythmia. Maybe that is what the digoxin is for. I have taken Propafenone and Rhythmal (similar) - and while they have (guess) helped me maintain sinus rhythm, they have never converted me to sinus, it has always taken other measures, electrocardioversion, in my case. Unfortunately, electrocardio.. no longer works on me.