Detailed Mx of AF in the ED

see also:

• AF main page
• cardiology
• cardiac arrhythmias
• atrial flutter
• calculators:
  • CHADS2 Score for Atrial Fibrillation Stroke Risk
  • CHA2DS2-VASc Score for Atrial Fibrillation Stroke Risk
  • ABCD2 Score for TIA
• NICS care bundle of documents to assist in the ED management of TIA and stroke
• AHA/ASA Guidelines - Guidelines for Prevention of Stroke in Patients With Ischemic Stroke or Transient Ischemic Attack
• Eur. Heart J. 2012: 2012 focused update of the ESC Guidelines for the management of atrial fibrillation
• European Heart Journal Guidelines for the management of atrial fibrillation (pdf)
• ACC/AHA Focused Update: Management of Atrial Fibrillation Jan 2011:
  • aiming for a resting heart rate of <110 beats per minute is preferable to more strict rate control
  • patients considered poor candidates for warfarin treatment, a combination of clopidogrel and aspirin appeared to be more efficacious than aspirin alone but also conferred a higher bleeding risk
• NICS - rate or rhythm control for recurrent AF - 2008 (pdf)
• CHADS2 score for predicting stroke, bleeding risk in AF
• RMH study 2011 - long term fish oil appears to significantly reduce recurrence of persistent AF after cardioversion
• ED Management of Recent-Onset Atrial Fibrillation: What is the Evidence? - Ian Stiell - ICEM 2012 presentation (pdf)

• 1. If haemodynamically unstable (eg. BP< 80) with rapid ventricular rate then
  • ⇒ ensure senior support & consider immediate synchronised DC cardioversion (see below)
  • BUT NO defib if chronic AF as risk of DC reversion likely to outweigh benefit
• 2. Is it AF?
  • If so, is it chronic or paroxysmal.
• 3. Search for underlying cause if new AF:
  • % of emergency admissions with AF:
    • 47% ischaemic heart disease
      • NB. in new AF in those under 60yrs with no prior IHD or prior ischaemic chest pain, IHD is unlikely to be the cause.
    • 18% hypertension (in 50% cases - Framington Study)
    • 15% rheumatic heart disease
    • 4% thyroid disease
    • 17% other :-
      • cardiac:
        • sick sinus syndrome
        • pre-excitation syndromes (e.g. WPW)
          • a very fast rate > 200 +/- variable QRS morphology suggests an accessory pathway
        • cardiomyopathy
        • pericarditis
        • ASD
        • atrial myxoma
        • short QTc - rare, but this may be life threatening!
      • non cardiac:
        • acute infections, esp. pneumonia
        • alcohol excess, withdrawal or sensitivity
        • lung carcinoma
        • other intrathoracic pathology (e.g. pleural effusion)
        • post-op (esp. after thoracotomy)
        • pulmonary embolism
• 4. Are there any precipitating factors present?
  • AMI
  • acute respiratory distress
  • acute alcohol ingestion
  • thyrotoxicosis
  • sepsis
• 5. Is cardioversion appropriate?
  • It is generally considered that unless patient is severely compromised due to the AF, the risks of DC reversion probably outweigh the benefits as:
    • most paroxysmal AF will revert of its own accord within 48hrs
    • risk of stroke from dislodging an atrial thrombosis - particular if chronic AF or new AF > 48hrs
    • DC reversion may in itself create a pro-thrombotic state of the atria
    • to be prudent, one should liaise with the cardiology unit first before undertaking semi-elective reversion as they should have a TOE performed first, and many advise therapeutic anticoagulation for at least 3 weeks prior to cardioversion and then for 4 weeks after successful cardioversion¹⁾
  • sync. DC cardioversion in the ED is probably only warranted if either:
    • haemodynamic compromise due to rapid AF
    • wide QRS complexes
    • after discussion with cardiology in patients who either have:
      • TOE evidence of no thrombi
      • perhaps very short duration AF with no risk factors, particularly if WPW as these pts have higher risk from rate controlling agents.
      • Atrial flutter or WPW as rate control not useful
      • Consider initial 200J DC with propofol and fentanyl
• 6. Determine long term or ongoing Rx:
  • If ongoing AF or high risk of intermittent AF then consider ongoing Rx:
    • rate control aiming for ventricular rate < 110 beats/min:
      • this will relieve symptoms of congestive heart failure, hypotension or angina that can be directly attributed to a rapid heart rate.
      • 36% will present in CCF, 10% as AMI, 8% as angina.
    • anti-thrombotic therapy:
      • this is the ONLY long term Rx shown to decrease mortality in pts with AF.
      • start anticoagulation if:
        • CHA2DS2-VASc score for determining stroke risk in patients with non-valvular AF = 2 or more, AND,
        • benefits outweigh risks of anticoagulation such as (see antithrombotic Rx for prevention of stroke):
          • age > 75yrs
          • on aspirin, clopdogrel or NSAIDs
          • polypharmacy and compliance issues
          • PH peptic ulcer of haemorrhagic stroke
          • see HAS-BLED bleeding risk scoring tool for anticoagulation Rx
      • a new study seems to show dabigatran is safer and much more effective at preventing stroke in pts with AF than is warfarin.
    • in addition, if paroxysmal AF lasting > 48hrs:
      • consider referring to cardiology for echo & elective cardioversion:

• in particular, look for:
  • flutter (ie. flutter waves - seen best in inferior leads; usually 2:1 block with ventricular rate of 150)
  • pre-excitation syndromes (e.g. WPW) (esp. if young patient or rate > 200 or variable QRS morphology).
• DDx:
  • SVT - has regular RR interval but rapid AF the variability in RR may be subtle.
  • VT - AF with BBB may be difficult to distinguish from VT - check for regular RR interval of VT
  • atrial extrasystoles - P-waves should be visible.
  • multifocal atrial tachycardia - varying P waves preceding most QRS complexes
  • PAT with variable block
  • atrial flutter with variable AV conduction - consider a dose of adenosine to reveal the flutter waves.

• FBE ± clotting if on or possibly may start warfarin.
• Urea and Electrolytes
• cardiac enzymes if ? acute coronary syndrome
• TFTs if have not been done, although low pick up rate if 1st episode lone AF

• senior consultation & consider immediate DC reversion:
  • sedation/short GA with propofol and fentanyl
  • 150-200J synch DC reversion (see below)
  • monitor ECG, vitals for at least 1 hour after
  • if not anticoagulated and AF duration > 48hrs, start IV heparin or clexane

• pulmonary or intrathoracic pathology
• cardiac failure/heart size
• evidence of ASD

• with-hold AV nodal blocking agents
• consider atropine, temporary pacing

• emergent DC reversion:
  • sedate
  • synch 150-200J biphasic DC reversion (if WPW, ensure defibrillator is detecting QRS and not the T wave otherwise you may get VF! Consider using different lead to detect QRS complexes)
  • if fails and not WPW or aberrancy, give amiodarone 5mg/kg iv over 10-20 minutes, then attempt DC reversion again
  • continue amiodarone infusion for 24hrs

• (i) pre-excitation syndrome such as WPW:
  • avoid AV nodal blockers such as digoxin, amiodarone, beta adrenergic blockers and calcium channel blockers
  • consider DC reversion or consider class Ia, Ic
• (ii) cardiac failure and poor cardiac function:
  • amiodarone 5mg/kg iv
  • or consider IV diltiazem if cardiac failure not too severe and not hypotensive
  • avoid negative inotropes such as verapamil and beta adrenergic blockers
• (iii) most other patients
  • consider a beta blocker such as:
    • metoprolol 25 mg tds po or 5mg iV (repeat if necessary)
    • (IV esmolol if worried about risk of beta blockers as short acting)
    • (some favour sotalol 80mg bd orally)
    • C/I: asthma/COPD, uncontrolled heart failure, sick sinus syndrome, heart block, hypotension, severe peripheral vascular disease (PVD or PAD)
  • or a calcium channel blockers such as:
    • verapamil (Isoptin) 40 mg tds po or 5 mg iV
    • C/I: heart failure, hypotension, sick sinus syndrome, heart block, AF with WPW, VT, pregnancy & breast-feeding
  • or amiodarone 5mg/kg iv
• (iv) consider pharmacologic cardioversion if AF duration < 48hrs and age < 50 and no structural heart disease:
  • ie. “lone AF”
  • NB. ~60% with paroxysmal AF will revert without drugs or DC reversion
  • avoid calcium channel blockers in this group as it tends to prolong duration of AF - see here
  • young adult, no underlying structural cardiac disease
    • flecainide 200-400mg orally or 2mg/kg IV (max 150mg) over 10 mins can be used as it is more effective than amiodarone in expediting reversion (~80% vs 40-60% at 8hrs while placebo had ~40% reversion)
      • flecainide is C/I in LV systolic dysfunction and probably should NOT be used unless echocardiogram first.
      • 10% develop hypotension or bradycardia if use 2mg/kg dose 
        • best bets.org
        • best bets.org 
  • other patients
    • amiodarone 5mg/kg IV over 60min but this is controversial

• if still in AF at 24-48hrs post onset then consider admitting for semi-elective DC reversion if < 48hrs duration:
  • discuss with cardiology
  • it may be that a -ve D-Dimer may assist in selecting pts safe to DC revert - see here
  • for every 100 pts with AF > 48hrs, 66 would avoid the need for TOE or anticoagulation at the cost of 1 pt having a false negative for mural thrombus.
  • S/C clexane then DOAC if AF duration likely to be > 24-48hrs
  • fast patient prior to sedation/short GA
  • synchronised DC with sedation - generally use propofol and fentanyl
  • 100J, step up to 360J in increments as needed
  • monitor ECG, vitals for at least 1 hour after

• if paroxysmal AF in patient < 50yrs and no structural heart disease:
  • consider no therapy as most will revert spontaneously within 24hrs (Am J Cardiol 1995 75:693-697)
  • ⇒ consider metoprolol for rate control
  • ⇒ consider clexane S/C
  • ⇒ once underlying causes excluded, discharge home for LMO or cardiology R/V within 48hrs of onset of AF & if still present then patient will need to be considered for:
    • semi-elective cardioversion if duration <48hrs 
    • otherwise, ongoing anticoagulation, rate control +/- elective cardioversion
• otherwise (eg. persistent or permanent AF, or known IHD, valvular heart disease or over 50yrs):
  • check adequate long term rate control and reassess risk/benefits of anticoagulation
  • long term rate control:
    • digoxin - not as good for exercise-induced AF; but useful in the elderly and those with cardiac failure;
    • metoprolol - better for exercise-induced AF, better rate control than amiodarone and digoxin and safer than sotalol which has risk of torsades.
• post-cardioversion:
  • if AF duration was > 48hrs, anticoagulation is continued for 4 weeks after cardioversion as atrial stunning may persist
  • risk of relapse of AF after cardioversion is high without antiarrhythmic drugs which are particularly of benefit in the first 3 months if an identifiable cause has been corrected.
  • percentage of patients remaining in SR if no antiarrhythmics
    • 69% at 1 month
    • 58% at 6 months
    • 23% at 1 year
    • 16% at 2 years.
  • with prophylactic antiarrhythmic therapy up to 80% will still be in SR at 12 months, even with a dilated LA as long as no other poor prognostic factors are present:
    • the risks of long term anti-arrhythmics such as sotalol or amiodarone for recurrent AF probably outweighs the benefit and for most patients a rate controlling agent +/- warfarin is preferred.

• admission is usually only warranted if:
  • ongoing haemodynamic instability
  • unable to get ventricular rate < 110/minute for 2hrs
  • unable to mobilise to usual level
  • cardiac failure
  • disturbing symptoms
  • other issues that mandate admission
• ideally for lone AF patients with persistent AF (no structural heart disease or risk factors and new AF):
  • review in 24hrs for a transthoracic echocardiogram to exclude structural abnormalities and check rhythm status then decide on need for long term anticoagulation.
  • unfortunately, TTE availability is often substantially delayed so referral and OP cardiology consult is reasonable +/- anticoagulation in the interim if patient is in the higher risk categories for stroke or if there is a possibility cardiology will perform semi-elective DC cardioversion.