Acute onset atrial fibrillation (AF)

• Rate and rhythm control (1)
  • carry out emergency electrical cardioversion, without delaying to achieve anticoagulation, in people with life-threatening haemodynamic instability caused by new-onset atrial fibrillation
  • in people with atrial fibrillation presenting acutely without life-threatening haemodynamic instability:
    • offer either rate or rhythm control if the onset of the arrhythmia is less than 48 hours
    • offer rate control if onset is more than 48 hours or is uncertain
      
      
  • in people with atrial fibrillation presenting acutely with suspected concomitant acute decompensated heart failure, seek senior specialist input on the use of beta-blockers and do not use calcium-channel blockers
    
    
  • consider either pharmacological or electrical cardioversion depending on clinical circumstances and resources in people with new-onset atrial fibrillation who will be treated with a rhythm control strategy
    
    
  • if pharmacological cardioversion has been agreed on clinical and resource grounds for new-onset atrial fibrillation, offer:
    • flecainide or amiodarone if there is no evidence of structural or ischaemic heart disease or
    • amiodarone if there is evidence of structural heart disease
      
      
  • in people with atrial fibrillation in whom the duration of the arrhythmia is greater than 48 hours or uncertain and considered for long-term rhythm control, delay cardioversion until they have been maintained on therapeutic anticoagulation for a minimum of 3 weeks. During this period offer rate control as appropriate
    
    
  • do not offer magnesium or a calcium-channel blocker for pharmacological cardioversion

Anticoagulation (1)

• in people with new-onset atrial fibrillation who are receiving no, or subtherapeutic, anticoagulation therapy:
  • in the absence of contraindications, offer heparin at initial presentation
  • continue heparin until a full assessment has been made and appropriate antithrombotic therapy has been started, based on risk stratification
    
    
• in people with a confirmed diagnosis of atrial fibrillation of recent onset (less than 48 hours since onset), offer oral anticoagulation if:
  • stable sinus rhythm is not successfully restored within the same 48-hour period following onset of atrial fibrillation or
  • there are factors indicating a high risk of atrial fibrillation recurrence or
  • anticoagulation is recommended because of stroke risk (see linked item)

In people with new-onset atrial fibrillation where there is uncertainty over the precise time since onset, offer oral anticoagulation as for persistent atrial fibrillation (1)

Indications for Emergency Rhythm Control (2)

Patients with ongoing atrial fibrillation at the time of initial evaluation, as confirmed by 12 lead electrocardiography, and

• with very slow or rapid ventricular rates (typically <40 bpm and >150 bpm),
• evidence of hemodynamic instability,
• severe symptoms,
• or decompensated heart failure
  
  
• should be referred to the emergency department for stabilization and possible electrical cardioversion
• in case of unknown duration of atrial fibrillation
  • cardioversion should be preceded by transesophageal echocardiography to rule out intracardiac thrombus
  • patients are required to be on anticoagulation for at least four weeks after electrical cardioversion to reduce the risk of thromboembolism

Reference:

• NICE (April 2021). Atrial fibrillation: the management of atrial fibrillation
• Ponamgi SP et al. Screening and management of atrial fibrillation in primary care. BMJ 2021;372:mn379 http://dx.doi.org/10.1136/bmj.mn379