I am 41 years old and have mild mitral stenosis. I had some membrane removed from my aortic valve when I was 15. So my heart is not normal, but healthy enough not to get in my way as long as I don't try compete in running or riding races, or field sports.
In April I had atrial fibrillation. I was electro-cardioverted and returned to normal rhythm and was taken off all meds except blood thinners. In September the A-fib came back and I was electro cardioverted again and have now being put on CR 200mg Flecainide (1 pill a day). I have no side effects except how it holds me back when my heart rate increases to about 145 bpm.
Sustaining the level of exertion at a higher HR than that (which I need to do when I am jogging on anything but the flatest of flat smooth roads) becomes really hard work. I usually can't sustain that level of effort for more than a few minutes which is when I need to take a break and let my HR return to 130 and then I can start again .. and repeat if the HR goes up that high again.
I have seen elsewhere that this is quite a normal effect of flecainide so I am not concerned about it. I am also accepting that I can't run at the speeds i did in the days before flecainide (not that i was breaking any records). But I am interested to hear from others that have tried to stay fit, and/or get fitter, on flecainide.
Whats the best approach? Is it best just to go for long slow runs on flat roads or is there benefit in exerting oneself to the point where you have to stop (effectively doing low intensity interval training!)?
BTW I also mountain bike, but haven't done that much recently (the reason has nothing to do with the A-fib) - when I ride, my heart rate is lower so the flecainide doesn't get in the way nearly as much.