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

Device-based Rate Versus Rhythm Control Treatment in Patients With Symptomatic Recent-onset Atrial Fibrillation in the Emergency Department (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.

Until recently standard of care for patients with recent-onset atrial fibrillation (AF) was early cardioversion. This has just been expanded with a delayed cardioversion approach. However, considering the recurrent and transient nature of AF, cardioversion might not be needed at all and rate control medication might be sufficient to accomplish spontaneous conversion to sinus rhythm. The aim of this trial is to evaluate effectiveness (presence of sinus rhythm) of a watchful-waiting approach, i.e. symptom reduction through rate-control medication and monitoring until spontaneous conversion is achieved compared to routine care, consisting of either early or delayed cardioversion. The trial is a multicentre prospective, randomized, open label, non-inferiority trial comparing the interventional watchful-waiting approach to routine care (control).The primary endpoint (presence of sinus rhythm), will be assessed after 4 weeks. The total follow-up time is 1 year.

Inclusion Criteria:

• ECG with atrial fibrillation
• Duration of the current AF episode <36 hours
• Symptoms due to atrial fibrillation
• Age > 18 years
• Able and willing to sign informed consent
• Able and willing to use telemetric rhythm recorder

Exclusion Criteria:

• History of persistent AF (episode of AF lasting more than 48 hours and terminated by cardioversion)
• Deemed unsuitable for participation by attending physician
• Hemodynamic instability (heart rate >170 bpm, systolic blood pressure <100 mmHg)
• Acute heart failure
• Signs of myocardial infarction
• History of syncope of unexplained origin
• History of untreated Sick Sinus Syndrome
• History of untreated Wolff-Parkinson-White syndrome
• Currently enrolled in another clinical trial