AF medication and exercise


I've been suffering from intermittent lone Atrial Fibrillation for about 18
months (30hours every 5 weeks approx) - cardiologist wants me to take
Flecainide (Tambocor) 50mg BD, rising to 100mb BD if necessary, for a year
to try and keep me in Sinus rythym - he said doing that may keep me out of
AF in the future. He couldn't guarantee I wouldn't have to stay on
Flecainide permanently though. But I really don't want to go on long term
medication if I can possibly avoid it.

The alternative suggested by my doctor is to take Propanalol 10mg-20mg three
times a day as a "tablet in the pocket" when I go into AF. However I am
supposed to switch to Flecainide if the episode persist, which unfortunately
they are. Initial use suggests Propanolol is more effective at stopping the
AF but probably not as good a long term answer as Flecainide.

I am a keen runner - does anyone know which medication would be better from
the point of view of least impact on performance in exercise?

Thanks for any help