Therapeutic considerations in applying rate control therapy for atrial fibrillation.

The therapeutic strategy of heart rate control for atrial fibrillation (AF) is undergoing a renaissance since several recent randomized trials demonstrated clear advantages over the rhythm control for many patients. Heart rate control for AF is hampered, however, by a dearth of information relating target heart rates to physiological measures or clinical outcomes. In this review, the rather sparse rationale behind the data elements for heart rate control - resting heart rate, activity heart rate, and regularity of the heart rate, is outlined. Beat-to-beat stroke volume is probably a key variable for calibrating heart rate targets. Presently it seems reasonable to propose targets for resting and activity heart rates but not for regularity. It also seems plausible but remains unproven that there should be a range (upper and lower) of heart rate targets rather than a simple upper limit. Nevertheless, it remains to be demonstrated through randomized clinical trials how to apply various heart rate control targets in patients with AF and whether complexity offers any advantage over simplicity.