Atrial fibrillation is a disease where the heart rhythm is irregular (this is called arrhythmia) and too fast (this is called tachycardia, from the Greek "tachy" meaning fast). Atrial fibrillation may produce complications, either in the heart (heart failure, syncope) or in other organs (mainly causing embolisms, which is the formation of blood clots in the cavities of the heart that may then travel to other places, for example the brain).
Atrial fibrillation can be reverted, restoring normal heart rhythm, by using drugs or a controlled electrical shock. However, a major problem is that atrial fibrillation recurs frequently. A variety of drugs have been employed to avoid recurrences and keep normal heart rhythm. This systematic review looked at the effectiveness and safety of antiarrhythmic drugs used to prevent recurrences of atrial fibrillation.
We found 45 good quality studies testing various antiarrhythmic drugs, involving 12,559 patients. The cumulative data from these studies show that several drugs are effective at preventing recurrences of atrial fibrillation (quinidine, disopyramide, flecainide, propafenone, amiodarone, dofetilide, dronedarone and sotalol), but all of them increased adverse effects. The data shows also that one specific group of drugs (called "class IA", and comprising quinidine and disopyramide) may cause a small increase in the number of deaths in treated patients. A limitation of the review was that most of the studies did not assessed the complications associated with atrial fibrillation (heart failure, stroke, embolisms), so the effect of antiarrhythmic drugs on these endpoints is unknown.
It is unclear if the long-term benefits obtained with antiarrhythmic drugs outweighs their risks.