Atrial fibrillation (AF) is one of the most common dysrhythmias encountered in the ED. The management of recent-onset AF and atrial flutter (AFl) in the ED continues to be debated. The discussion centers on whether patients with recent-onset AF should be rhythm controlled (e.g. converted back to sinus rhythm) or rate controlled only. This debate was showcased in a point-counterpoint in Annals of Emergency Medicine in 2011 (Stiell 2011, Decker 2011). The rhythm control supporters argue that AF/AFl is abnormal, worsens quality of life, leads to cardiac remodeling and, in may patients, requires medications for rate control and anticoagulation. The rate control group argues that cardioversion runs the risk of causing a thromboembolic event (i.e. CVA, peripheral arterial occlusion). Thus, it should not be performed until the absence of clot in the left atrium is confirmed (by TEE) or appropriate anticoagulation has occurred. It has long been taught that if the patient has been in AF/AFl for < 48 hours, the risk of developing a clot in the left atrium is negligible and cardioversion may be pursued. However, some recent literature has called this classic teaching into question (Nuotio 2014). Prospective studies looking at outcomes of recent-onset AF/AFl patients after aggressive treatment in the ED are needed to further evaluate the risks of aggressive treatment.

Clinical Question

What is the rate of adverse events occurring within 30 days of ED presentation for recent-onset AF/AFl in a system that utilizes an aggressive approach to management?


Patients presenting to 6 academic hospital EDs with recent-onset AF/AFl defined as a clear onset within 48 hours, clear history of onset within 7 days and on adequate anticoagulation or a clear history of onset within 7 days and the absence of left atrial thrombus on TTE.


Primary: Death, stroke, acute coronary syndrome, heart failure, subsequent readmission or subsequent electrocardioversion at 30 day follow up


Prospective cohort study


Patients previously enrolled, permanent/persistent atrial fibrillation, primary presentation for another indication (i.e. ACS, CHF w/ severe shortness of breath, pneumonia, PE or sepsis)

Primary Results

  • 1091 out of 1120 eligible patients enrolled
  • Mean age 63.9 years
  • 72.8% of patients treated with electrical or pharmacologic cardioversion
  • Procainamide was the most common drug used for pharmacologic cardioversion (84.9%)
  • 9% of patients admitted to the hospital
  • 80.1% of patients discharged in sinus rhythm

Critical Results

  • Adverse events at 30 days
    • 15.4% of patients returned to the ED for an AF/AFl related issue
    • 4 deaths (none related to AF/AFl)
    • Stroke
      • 1 patient experienced a stroke 23 days after presentation
      • Patient was on warfarin with therapeutic INR on presentation
      • Spontaneously converted to NSR in ED
    • Recurrent cardioversion: 6.5%
    • Subsequent AF/AFl related hospitalization: 3.2%
  • Anticoagulation assessment
    • 57.8% of patients with CHADS2 score > 1
    • 32.1% of patients on warfarin at presentation
    • New oral anticoagulant prescribed to 8.9% of patients
  • Patients discharged in sinus rhythm were less likely to experience adverse events


  • Largest multicenter prospective study looking at outcomes after ED management of recent-onset AF/AFl
  • Gives further information on low rate of anticoagulation prescription after AF/AFl presentation
  • Further supports aggressive approach to recent-onset AF/AFl management given low serious adverse event rate both in the hospital as well as during follow up
  • Data demonstrates an association between discharge in sinus rhythm and lower rate of adverse events


  • Follow up performed by phone interview introducing recall bias
  • Direct rhythm assessment not performed at follow up. Possible that patients were not in sinus rhythm during their follow up period
  • Unclear why patients managed with one approach versus another (patients were not randomized)
  • Adverse event rate was a composite of multiple outcomes which are not all equivalent outcomes

Author's Conclusions

“Although most recent-onset atrial fibrillation and flutter patients were treated aggressively in the ED, there were few 30-day serious outcomes. Physicians underprescribed oral anticoagulants. Potential risk factors for adverse events include longer duration from arrhythmia onset, previous stroke or transient ischemic attack, pulmonary congestion on chest radiograph, and not being in sinus rhythm at discharge. An ED strategy of sinus rhythm restoration and discharge in most patients is effective and safe”

Our Conclusions

An aggressive approach to the management of recent-onset AF/AFl centered on cardioversion was not associated with a high rate of serious outcomes at 30-days and appears to be a safe strategy based on . Only a single patient experienced a stroke and this occurred 23 days after discharge in a patient who spontaneously converted to sinus rhythm.

Potential Impact To Current Practice

This data lends further support to taking an aggressive approach to the management of recent-onset AF/AFl in the ED. Based on this evidence it appears reasonable to adopt an approach focused on restoring sinus rhythm in the ED. The low rate of anticoagulation in appropriate patients also challenges current practice. There should be added consideration for starting an anticoagulant in appropriate patients.

Bottom Line

An aggressive approach to the management of recent-onset AF/AFl did not result in an unacceptable rate of adverse events. Adopting a rhythm control approach in these patients appears safe.

Read More

The SGEM: Shock Through the Heart (Ottawa Aggressive Atrial Fibrillation Protocol)

Core EM: Ottawa Aggressive Atrial Fibrillation Protocol

Core EM: Recent-Onset Atrial Fibrillation