6th March 2024

Management

This focuses on rate and/or rhythm control and anticoagulation to reduce stroke risk. NICE guidance on when rhythm control is more appropriate over rate control includes patients with new-onset AF, those with a reversible cause, AF leading to LV dysfunction, or those with flutter amenable to ablation. Rhythm control is also considered where rate control strategies have failed or symptoms persist despite adequate rate control.

Rate control involves beta blockers or rate limiting calcium channel blockers (preferential in asthmatics) as first line, or digoxin if there are concerns for LV dysfunction. In the event of an accessory pathway (i.e. pre-excited AF) then AV nodal blocking agents should be avoided as they reduce the buffering effect of the AV node and allow the atrial arrhythmia to degenerate into a ventricular arrhythmia. Therefore, in the event of pre-excited AF, class 1a, 1c and 3 antiarrhythmics are utilised, including procainamide, flecainide and amiodarone, respectively. If the onset of AF is <48 hours, rate control should be initiated, and if the rhythm does not return to the sinus within 24 hours, consideration can be made for cardioversion using flecainide if there is no underlying evidence of coronary disease or LV dysfunction. Alternatively, Amiodarone may be used. Most episodes of AF will resolve spontaneously, especially where there is an underlying cause, such as infection. In the event of haemodynamic compromise, returning to sinus rhythm is a priority using direct current cardioversion. Beyond 48 hours of onset or where the timeline is unclear, rate control and anticoagulation for at least 3 weeks with either warfarin or a DOAC is initiated in preparedness for outpatient cardioversion. Amiodarone can be given prior to cardioversion to increase the likelihood of success. 

Anticoagulation is continued for 4 weeks following cardioversion in low-risk patients. The CHA2DS2-VASc score (Table 2) is used to assess the need for long term anticoagulation.  The HAS-BLED score has been superseded by the ORBIT score in assessing bleeding risk. Scoring high encourages caution with oral anticoagulation and a review of bleeding risk factors. Catheter ablation may be used in AF but following a single procedure may return in up to 20-30% of patients.

 Table 2: CHA2DS2-VASc score determines stroke risk in patients with AF. Score of 2 or more warrants anticoagulation. A score of 1 in men warrants consideration.