Device-based Rate Versus Rhythm Control in Symptomatic Recent-onset Atrial Fibrillation (RACE 9 OBSERVE-AF)

Continuous heart rhythm monitoring elucidated the recurrent and transient nature of recent-onset atrial fibrillation (AF). The RACE7 ACWAS showed that a wait-and-see approach (WAS) in patients with recent-onset AF (rate control for symptom relief followed by delayed cardioversion if needed <48h) allows spontaneous conversion to sinus rhythm in 69% of patients, obviating active cardioversion. Recurrences within one month were seen in 30% of patients in both groups, i.e. the initially chosen strategy did not affect the recurrence pattern. Considering the latter, it remains unclear whether cardioversion is needed at all, especially since cardioversion strategy does not seem to affect behaviour of the arrhythmia over time. Instead of cardioversion a watchful-waiting rate control strategy may be appropriate as initial strategy. This allows observing the electrical and clinical behavior of arrhythmia, providing a solid basis for comprehensive and effective early rhythm control. This study is a multi-center clinical randomized controlled trial to show non-inferiority of watchful-waiting with rate control versus routine care in terms of prevalence of sinus rhythm at 4 weeks follow-up, using a novel telemonitoring infrastructure to guide rate control during follow-up.