Is vernakalant better or not, compared with other treatments for conversion of acute atrial fibrillation?

Vernakalant has proved to be more rapid in converting recent onset AF to sinus rhythm compared to placebo, amiodarone, propafenone and flecainide. In many centers around the world the electrical cardioversion is the first line of treatment of acute atrial fibrillation. Recently a group published that vernakalant had a 90% conversion rate in patients with recent onset atrial fibrillation without structural heart disease versus 100% conversion rate in the electrical cardioversion group. In this study there was no statistical differences between both groups (p=NS). Vernakalant has been approved in Europe and South America, but it has not been approved in the United States and Canada. FDA wants a megatrial to show the real benefits of vernakalant compared to other drugs including electrical cardioversion. The trial ACT V has been canceled because one patient who received vernakalant died and this is the reason why FDA has not approved vernakalant yet. We do not know the real condition of the patient and if it was corrected to conclude that the severe adverse event had a direct relationship with the drug. I can conclude that it is time to design a megatrial to show if vernakalant is better or not for conversion of recent onset atrial fibrillation compared with other antiarrhythmic drugs and electrical cardioversion because all the topics about this drug have been published but in brief reports. We need a big trial to know the real safety of this drug.