Comparing watchful waiting to cardioversion for recent-onset atrial fibrillation

Device-based Rate Versus Rhythm Control Treatment in Patients With Symptomatic Recent-onset Atrial Fibrillation in the Emergency Department (RACE 9 OBSERVE-AF)

Not applicable Interventional Maastricht University Medical Center · NCT04612335

This study is testing if a watchful-waiting approach for recent-onset atrial fibrillation can work just as well as the usual treatment that includes heart rhythm restoration.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment490 (estimated)
Ages18 Years and up
SexAll
SponsorMaastricht University Medical Center Academic / other
Locations14 sites (Maastricht, Limburg and 13 other locations)
Trial IDNCT04612335 on ClinicalTrials.gov

What this trial studies

This trial evaluates the effectiveness of a watchful-waiting approach for patients with recent-onset atrial fibrillation (AF) compared to standard care that includes early or delayed cardioversion. Participants will receive rate control medication and be monitored for spontaneous conversion to sinus rhythm over a period of four weeks. The study is a multicenter, randomized, open-label trial designed to assess whether the watchful-waiting strategy can achieve similar outcomes to routine care. The total follow-up for participants will last one year, allowing for comprehensive assessment of AF behavior and treatment efficacy.

Who should consider this trial

Good fit: Ideal candidates are adults over 18 years old experiencing symptomatic atrial fibrillation episodes lasting less than 36 hours.

Not a fit: Patients with a history of persistent atrial fibrillation or those with hemodynamic instability will not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could reduce the need for invasive cardioversion procedures, leading to better patient comfort and lower healthcare costs.

How similar studies have performed: Previous studies have indicated that a watchful-waiting approach can be effective, suggesting potential success for this trial's methodology.

Eligibility criteria

Show full inclusion / exclusion criteria
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

Where this trial is running

Maastricht, Limburg and 13 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Atrial FibrillationAtrial fibrillationCardiac arrhythmiaCardioversionElectrical cardioversionWatchful waitingWait-and-seeTelemonitoring
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.