Atrial Fibrillation: In Search for the Optimal Target for Rate Control

For patients in the ivabradine arm targeting for strict rate control, ivabradine is started at 5mg BID, and titrated at follow-up visits if needed, up to 7.5mg BID to aim at the target heart rate \<80bpm. Uptitration of other existing or additional conventional rate control agents will considered after maximally tolerated dose of ivabradine. Conversely, if not tolerated, or if resting heart rate is persistently \<50bpm, ivabradine will be reduced to 2.5mg BID, followed by reassessment.

For patients in the lenient rate control arm, medications will be adjusted, bidirectionally as appropriate, with a maximum heart rate that is tolerable by patient which is at \<110bpm. Routine heart rate control agents included betablockers, nondihydropyridine calcium channel blockers, or digoxin. All patients will be prescribed a matching placebo (morphologically identical to the comparison arm: ivabradine) that contains pharmacologically inactive cellulose.