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Mastering the Crisis: Effective Management of Atrial Fibrillation with Tachycardia in the ED

Mastering the Crisis: Effective Management of Atrial Fibrillation with Tachycardia in the ED
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Management of Atrial Fibrillation (AF) with Tachycardia in the Emergency Department

Managing patients with acute atrial fibrillation (AF) presenting with tachycardia in the ED requires a systematic and evidence-based approach. Here's a detailed suggested guide to assist you:

Haemodynamic Instability

Mastering the ability to discern between stable and unstable patients is crucial for effective clinical decision-making. That is your first step.

You need to learn to differentiate a stable from an unstable patient

  • Characteristics of an unstable patient:
    • Symptomatic low systolic blood pressure (SBP < 100 mmHg or lower than usual)
    • Poor peripheral circulation
    • Moderate to severe angina,
    • Ischaemic ECG changes
    • Acute heart failure
    • Poor cerebral perfusion.
  • If you decide that your patient is unstable then the first step is to ensure that you will not cardiovert the patient under these circumstances:
    • DC Cardioversion (DCC) Risks:
      • Assess for digoxin toxicity and severe hypokalaemia (K+ < 3.0 mmol/L). Hopefully, you know what will happen if you use electricity in these two risky scenarios.

"Watch out for this." Patient with WPW and AF

Atrial fibrillation (AF) in the context of Wolff-Parkinson-White (WPW) syndrome presents unique challenges and risks. WPW syndrome is characterized by the presence of an accessory pathway (AP) that can lead to rapid anterograde conduction, potentially causing life-threatening ventricular fibrillation if AF occurs. 

Wolff-Parkinson-White Syndrome (WPW)

  • Indicators: History of WPW, delta wave on previous ECG, or rapid (> 200 bpm) wide complex tachycardia ± polymorphic QRS.
  • Treatment:
    • Direct current cardioversion is the treatment of choice for patients with WPW syndrome and AF, according to multiple sources. It rapidly terminates the dysrhythmia and restores normal sinus rhythm.
    • Avoid adenosine, non-dihydropyridine calcium channel blockers, β-blockers, amiodarone, and digoxin.
    • If the patient doesn’t consent, refer to cardiology for IV antiarrhythmics.

Moving forward you decide that your patient is stable, then you need to decide when the AF may have started

  • If you decide that your patient is stable, then find out the onset time for the arrhythmia:
    • Onset < 48 hours: Perform urgent DCC ± antithrombotic therapy.
    • Onset ≥ 48 hours or uncertain:
      • If adequately anticoagulated for at least 3 weeks, proceed with urgent DCC.
      • If not anticoagulated, consult cardiology for TOE-guided cardioversion ± antithrombotic therapy.

Onset < 48 Hours - You have two options here:

  • Rate Control ± Antithrombotic Therapy:
    • Preferred in patients aged ≥ 65 with asymptomatic, recurrent AF, untreated reversible cause, history of congestive heart failure, valve disease, prosthetic valve, or coronary artery disease. Consult cardiology if needed.
    • Consult neurology if stroke or TIA in the last 4 weeks.
  • Rhythm Control ± Antithrombotic Therapy:
    • Preferred if no indication for rate control or if there are unacceptable arrhythmia-related symptoms (e.g., palpitations, dizziness, fatigue, dyspnoea), acute heart failure, inability to tolerate rate-control drugs, or pre-excitation.
    • Consider the "Wait and See" approach with rate control + antithrombotic therapy and ED review within 24 hours for stable PAF < 24 hours (≈ 60% revert spontaneously within 48 hours).
Onset ≥ 48 Hours or Uncertain
  • If adequately anticoagulated for at least 3 weeks, treat as onset < 48 hours.
  • If not anticoagulated, use rate control ± antithrombotic therapy. TOE-guided cardioversion is an option.

ED Investigations

  • Conduct FBP, U&Es, LFTs, ECG ± TFTs, ± CXR if heart failure, infection, or significant lung disease is suspected, and digoxin level if required.
  • Additional investigations as indicated for acute comorbid conditions.
  • Note: Serum Mg++ deficiency may not always be detected; BNP and troponin levels can be elevated without heart failure or coronary artery disease, respectively.

Rate Control Options (You must check your local guidelines for dosages)

  • Medications:
    • IV Metoprolol (1–5 mg slow push, repeat up to 15 mg).
    • IV Amiodarone (300 mg loading dose, followed by infusion or oral administration).
    • PO β-blockers (e.g., Metoprolol 25–50 mg BD).
    • PO non-dihydropyridine calcium channel blockers (e.g., verapamil, diltiazem).
    • Digoxin for resting tachycardia; IV digoxin is useful in the hypotensive patient.
    • IV Magnesium may be beneficial.
  • Management:
    • Admit if rate control is not achieved or other acute issues are present.
    • Discharge if heart rate (HR) ≤ 110.
    • Anticoagulate if CHA2DS2-VASc score ≥ 2, valvular heart disease, or planning elective DCC.
    • Follow up with GP and consider elective DCC after 3 weeks of anticoagulation if AF ≥ 48 hours.

About DC Cardioversion (DCC)

  • Procedure:
    • Ensure NPO for 4 hours and obtain consent (follow local guidelines).
    • May pre-treat with IV Amiodarone or Magnesium. Amiodarone may be beneficial in patients having AF for the first time but not in patients with established AF. For example, in a patient with a new AF and you have to wait for fasting 4 hour or more, use the time by giving Amiodarone.
    • Administer Enoxaparin 1 mg/kg if not contraindicated before cardioversion. Not everyone does it but Clexane can be used as part of the bridging anticoagulation strategy if immediate cardioversion is required.
    • Perform procedural sedation.
    • Use anterior-posterior pads (8 cm from implanted devices).
    • Initial synchronized shock: 150–200 J, repeat with higher joules if needed.
    • Discharge once sinus rhythm is restored and the patient recovers from sedation.
    • Continue anticoagulation for 4 weeks if CHA2DS2-VASc score ≥ 2.
    • GP follow-up and recommend OP Echocardiogram if structural/functional heart disease is suspected.

Chest Pain with Acute AF and Tachycardia – ACS?

  • Evaluate for ACS if moderate to severe chest pain consistent with angina, acute ST/T wave changes, or ECG changes consistent with acute STEMI.
  • Follow your Chest Pain Pathway if ACS is suspected.

Antithrombotic Therapy

  • Assess all patients for anticoagulation: Warfarin for valvular AF, NOAC for non-valvular AF.
  • Use CHA2DS2-VASc and HAS-BLED scores for risk stratification and management decisions:
  • CHA2DS2-VASc ≥ 2: Recommend anticoagulation.
  • HAS-BLED ≥ 3: Consult with cardiology before initiating anticoagulation.
CHADS₂ Score for Atrial Fibrillation Stroke Risk
The CHADS2 score estimates stroke risk in patients with atrial fibrillation.
MDCalc

NOAC Recommendations (Based on Therapeutic Advisory Group)

  • Apixaban (Eliquis®):
    • Patients with at least 2 risk factors for bleeding (ie age 80 years or older, weight 60 kg or less, and serum creatinine 133 micromol/L or more): 2.5 mg orally, twice daily
    • All other patients: 5 mg orally, twice daily.
  • Dabigatran (Pradaxa®):
    • Younger than 75 years and CrCl more than 50 mL/min: 150 mg orally, twice daily
    • Younger than 75 years and CrCl 30 to 50 mL/min, or increased risk of major bleeding: 110 mg orally, twice daily.
    • 75 years or older and CrCl more than 30 mL/min: 110 mg orally, twice daily.
    • Do not use dabigatran if calculated CrCl is less than 30 mL/min.
  • Rivaroxaban (Xarelto®):
    • CrCl 50 mL/min or more: 20 mg orally, once daily.
    • CrCl 15 to 49 mL/min: 15 mg orally, once daily.
    • Do not use rivaroxaban if the calculated CrCl is less than 15 mL/min. 
    • CrCl of 15 to 29 mL/min: consider its use in these patients under specialist advice.