ABSTRACT
Among supraventricular arrhythmias atrial fibrillation presents relatively unique regulatory concerns and will be the focus of this discussion. Some features of atrial fibrillation are not shared by some of the more organized supraventricular types of arrhythmias. In addition, atrial fibrillation is manifest in a very heterogeneous population. A problem in drug development is finding a specific population that truly may benefit from the therapy under study. Some subgroups of patients with atrial fibrillation feel well and are going to do well, and so, by giving a drug or by other intervention, all one can do is harm. However, there are other patients who feel ill and who are fated to do poorly, to have strokes, or to die; there is at least a possibility of doing good in these patients, but they must be identified first.
