Atrial fibrillation can be managed either by controlling the rate or trying to re-establish sinus rhythm. The pendulum is currently favoring the rate control strategy (with adequate anticoagulation)
I think the AFFIRM trial did the most to change medical opinion that rate control is an adequate strategy. Until then, we settled for rate control, but only after numerous attempts at regaining sinus rhythm. This trial suggested that rate control was not such a bad strategy.
My initial thoughts about the AFFIRM trial were that three months of anticoagulation after cardioversion is not adequate and I still think that can be inferred from the data. However, it is much more often quoted as a reason to move to rate control strategy and quit trying to re-establish sinus rhythm.
The original study on average enrolled 70 year old patients, 39% female, 26% with CAD and 23% with CHF. They followed for 3.5 years. The rate control group had significantly fewer hospitalizations and the trend was towards less all cause mortality and less CNS events.
This study certainly has become the cornerstone of the argument for rate control, although several other well done studies do point towards the same conclusions. However, patients enrolled into the study were essentially asymptomatic in Afib to get into the study. Many of the groups advocating rate control, omit that big limitation. The age also may be important, since strategies for 70 year olds may not fit a 30 year old, and the followup period was only 3.5 years.
I still think that the key to therapy is deciding whether a patient is truly asymptomatic. Often I will cardiovert the patient just to ascertain that they truly are asymptomatic. The truly asymptomatic, can be safely and effectively managed with a rate control strategy. But I think that the symptomatic patient is not who the AFFIRM trial addressed and should not be assigned to a rate control strategy initially.