In the wake of the AFFIRM trial: what we still don't know about the management of atrial fibrillation and where we need to go.

Five recent trials have been completed comparing the strategy of rhythm control to the strategy of rate control for the management of atrial fibrillation. These trials have demonstrated no clear advantage for the rhythm control strategy using current pharmacologic therapies and that anticoagulation should not be discontinued in high-risk patients, even when it appears that sinus rhythm has been restored and maintained. Although a broad-based research approach is needed to advance our understanding of therapeutic options for the management of atrial fibrillation, the results of these five trials serve to focus the research enterprise on management of this common and often vexing tachyarrhythmia. With this background, the focus of future research on atrial fibrillation is discussed under the following headings: epidemiology and patient taxonomy, pathophysiology, rhythm management and thromboembolism prophylaxis. In each area there are short-term and long-term goals. Some examples follow. The comparison of these two strategies needs to be extended to other large patient groups who have not yet been studied, such as those with heart failure, particularly diastolic dysfunction, and younger patients with paroxysmal atrial fibrillation. A better understanding of pathophysiology is necessary upon which to base a more rational approach to the problem of rhythm management in atrial fibrillation. A better understanding is needed of how to achieve "good" heart rate control. The role of nonpharmacologic therapies for maintenance of sinus rhythm needs more rigorous testing and we need better and safer drugs for this purpose. We need to understand better the relationships between atrial fibrillation and thromboembolism and we need alternatives to warfarin therapy. These and other research efforts are needed to make an impact on management of the problems of atrial fibrillation.