1. For patients with no high-risk factors for stroke (recent stroke or TIA within 6 months; rheumatic heart disease; mechanical valve) and clear AF-onset within 48 hours or therapeutic OAC therapy for ≥3 weeks, we recommend that they may undergo cardioversion in the ED without immediate initiation of anticoagulation. Following attempted or successful cardioversion, antithrombotic therapy should be initiated as per the CCS algorithm. (Strong recommendation, Moderate Quality Evidence)

Practical Tip: Either pharmacological or electrical cardioversion may be selected, depending upon physician and patient preference. For electrical cardioversion of AF, an initial QRS synchronized energy level of 150-200 joules is appropriate.

Practical Tip: Patients who are discharged from the ED after receiving or being considered for cardioversion of AF should have early expert follow-up to review the need for ongoing antithrombotic therapy.

2. For patients at high risk of stroke with cardioversion (not receiving therapeutic OAC therapy for ≥3 weeks with any of the following: AF episode duration not clearly <48 hours; stroke or TIA within 6 months; rheumatic heart disease; mechanical valve), we recommend optimized rate-control and therapeutic OAC for 3 weeks before and at least 4 weeks after cardioversion. (Strong Recommendation, Moderate Quality Evidence)

Practical Tip: When OAC-therapy is indicated, a NOAC is preferred over warfarin for most patients.

Practical Tip: Prior to discharge, patients should have their resting heart rate reduced to <100 beats/minute and their walking heart rate to <110 beats/minute.

Practical Tip: Patients should receive both OAC-therapy and appropriate oral ratecontrolling agents (beta-blocker or non-dihydropyridine calcium-channel blocker)

3. We suggest that patients at high risk of stroke (not receiving therapeutic OAC therapy for ≥3 weeks with any of the following: AF episode duration not clearly <48 hours; stroke or TIA within 6 months; rheumatic heart disease; mechanical valve) may undergo cardioversion guided by transesophageal echocardiography with immediate initiation of intravenous or low molecular weight heparin prior to cardioversion followed by therapeutic OAC for at least 4 weeks post cardioversion. (Conditional Recommendation, Moderate Quality Evidence)

Practical Tip: If a NOAC is not used post-TEE guided cardioversion, heparin bridging should be started immediately while warfarin is initiated.

4. For patients whose recent-onset AF/AFL is the direct cause of instability with hypotension, acute coronary syndrome, or florid pulmonary edema, we recommend that immediate electrical cardioversion be considered with immediate initiation of intravenous or low molecular weight heparin prior to cardioversion followed by therapeutic OAC for 4 weeks afterwards (unless AF-onset was clearly within 48 hours or the patient has received therapeutic OAC for >3 weeks) followed by therapeutic OAC for at least 4 weeks post cardioversion. (Strong recommendation, Low Quality Evidence)

Practical Tip: Caution is required in patients with permanent AF who present with instability as they may not benefit from cardioversion and may be made worse by attempts to do so.

Practical Tip: In patients with long standing AF and hemodynamic instability and a ventricular rate less than 150 beats per minute, the instability is likely due to causes other than AF (e.g. hypoxia, pain, sepsis) and is unlikely to respond to cardioversion.

Practical Tip: Immediate and adequate rate control may alleviate the clinical instability and obviate the need for immediate cardioversion.