Welcome SHEZ7557! You have come to the right place for both knowledge, help and support...
I have had atrial fibrulation since about 38 years old. Pacemaker about 2 years after that, (drugs didnt seem to work, and I ended up with a quack Doctor who tried to kill me three times before I changed to a more sane one!).
At least here, you will gain knowledge, support and friendship, and be able to "take charge" of your body while you whip it into shape...(yea, I know, "round" is a shape too, but, who wants to be in THAT kind of shape, eh? LOL!).
I dont know how much you can do, as I am very limited in what I can do, (If I do too much, I suffer the next day like its trying to kill me!), so, ya gotta do what you can, and pace yourself slowly... Just dieting wont make it (as I know from being stagnant for many months now), you GOTTA move somehow, someway to get those calories off you.
Look to the right, you will get exercise tips and if you can do any of them, the mroe the better, if not, maybe some 'form' of what they are doing would be good, but, even if its a 'gentle exercis', as long as you 'move', it will be a start to up your metabolism.
I wish you well in your venture...
May the LORD Bless you with Grace and Salvation, and if we dont meet in this life time, that we meet in the cloud when our SAVIOUR comes to claim HIS own...The Church.
I wish you well...