Flecainide
"After a number of inconvenient and stressful visits to ER where I had an injected dose of flecainide ( which put me back into sinus rhythm) my cardiologist prescribed me 200 mg of Flec tabs plus 50 mg of metropolol  on going into AF. It works a treat reversing me in 1 to 3 hours but I'm hoping doesn't lead to some of the side effects described in other articles on the net."