Unstable: AF with hypotension, altered mental status, chest pain (angina) or SOB (LV failure)
DC cardioversion beginning with 120-150 J biphasic provided that the AF is of recent onset (<48h)
A patient on digoxin therapy may require temporary transcutaneous pacing, as asystole can follow DC reversion
Stable
Duration <48 hours: Rhythm control with drugs or electrical cardioversion
50-60% of patients will spontaneously revert within 24 hours anyway, so observation may be all that is needed when the AF has been present for ≤12 hours
Correct hypokalaemia with 20 mmol potassium in 500 mL 5% dextrose over 30 minutes
Correct hypomagnesaemia (particularly in alcoholics) with magnesium sulfate 10 mmol (2.5 g) IV
Give amiodarone 300 mg IV over 30 minutes, followed by an infusion of amiodarone 900 mg over 24 hours. This is effective in up to 75% of patients. Continuous ECG monitoring is required.
Note: although flecainide and sotalol are more effective than amiodarone, they have dangerous side effects, including hypotension, and mandate senior advice before use
Commence heparinisation with a LMWH such as enoxaparin 1 mg/kg SC 12-hourly, or UFH 5000 U IV as a bolus, followed by an infusion commencing at 1000 U/h
Perform electrical cardioversion is above measures are unsuccessful
Duration >48 hours or time duration is unclear: Rate control only
Do not attempt cardioversion prior to full anticoagulation
Commence heparinisation with LMWH (e.g. enoxaparin) or UFH
Perform rate control using PO or IV beta-blocker, digoxin, diltiazem or magnesium
Continuous ECG monitoring is required when any agent is given IV (consider CCU care)
If the patient is completely asymptomatic or the AF has been present for several days
If patient has normal LV function (no past history or current evidence of LV failure or ↓ EF) give:
Metoprolol 2.5mg slow IV boluses up to a total dose of 10mg followed by 25-50mg twice a day thereafter
If the patient has documented or suspected depressed LV function give:
Digoxin 0.5mg slowly IV or PO repeated in 8 hours followed by 0.125-0.25mg PO daily thereafter
Atrial fibrillation with a ventricular rate <100 beats/min
AF <100 beats/min in an untreated patient suggests underlying AV nodal dysfunction ⇒ do not require immediate rate or rhythm control unless haemodynamically compromised (e.g. hypotension, chest pain or LV failure)
Start these patients on anticoagulation if no contraindications
Acute Management of Slow Ventricular Response
Does not require treatment unless the patient is hypotensive or has symptoms of vital organ hypoperfusion (e.g. syncope, confusion angina or LVF)
Definitive treatment includes discontinuation of any drug that depresses cardiac conduction and consideration for temporary or permanent pacemaker placement