TABLE OF CONTENTS
This question comes up again and again in atrial fibrillation (AF) management.
Many ER residents instinctively call cardiology just to decide whether to start amiodarone.
Most of the time, you don’t need a cardiology call to make the first decision.
Let’s simplify this.
Why do we care?
Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice.
AF is not a benign rhythm. It can cause
- Heart failure
- Tachycardia-induced cardiomyopathy
- Atrial clot formation
- Thromboembolism -Systemic embolization, ischemic stroke
- 1.5–2× increased mortality
First - Is this really AF? - Look at the ECG
- Two key things to look at
- Rhythm :
- Irregularly irregular rhythm
- P waves
- Absent P waves
- Fibrillatory waves (may mimic P waves)
- No isoelectric baseline
- Usually narrow QRS (<120 ms) (unless BBB, pre-excitation, or aberrancy)
Is the Patient Optimised?
Before chasing rhythm or rate, resuscitate first.
- Stabilise and optimise ABCs
- Correct precipitants: Think PIRATES
- P – Pulmonary embolism
- I – Ischemia (ACS, myocardial injury)
- R – Respiratory disease (COPD, pneumonia, hypoxia)
- A – Atrial enlargement / atrial myxoma
- T – Thyroid disease
- E – Ethanol / Electrolyte imbalance
- S – Sepsis, Stress, Surgery
Is the patient unstable?
Or a better question-
Is the tachycardia causing the instability?
Uncontrolled AF can:
- Impair ventricular filling
- Reduce cardiac output
- Decrease in coronary perfusion
- Increase myocardial oxygen demand
Assess instability — Think CHAAS
- C – Chest pain (ischemic)
- H – Hypotension
- A – Altered mental status
- A – Acute heart failure
- S – Signs of shock
Any one present = Unstable AF
DC cardioversion will stabilise the patient only if the AF is causing the instability.
It's Unstable AF - what now?
What to do?
Immediate management: Synchronised DC cardioversion
Unsynchronised cardioversion can precipitate VF
How to do?
- Initial energy: 200 J biphasic
Escalate in case of a shock failure
Why start high?
- A higher initial shock energy is more effective than a “start low and titrate up” approach
- Higher first-shock success
- Require fewer total shocks
- Shorten the duration of anaesthesia.
- A randomised trial showed that maximum fixed-energy shocks were more effective than a low-escalating energy strategy for electrical cardioversion.
- Low-energy monophasic shocks → more likely to provoke ventricular fibrillation.
- Pad positioning: There is no single optimal position
- A meta-analysis of 10 RCTs showed no difference in sinus rhythm restoration when comparing anterior-posterior with antero-lateral electrode positioning.
- EPIC Trial: Anterior-lateral electrode positioning was more effective than anterior-posterior electrode positioning for biphasic cardioversion of atrial fibrillation.
What to do after this?
Immediate administration of amiodarone (if possible) improves the rate of successful ECV.
Anticoagulation caution
AF >48 hours or unknown duration in non-anticoagulated patients carries thromboembolic risk
Ask first: Is your patient hemodynamically unstable?
YES — Unstable AF
- Immediate synchronised DC cardioversion
- Do not delay cardioversion for anticoagulation status
- Check OAC status as soon as feasible after cardioversion
- Post-cardioversion anticoagulation
- Start short-term OAC for all patients - (regardless of baseline stroke risk)
NO — Hemodynamically stable AF
- If anticoagulated ≥ 3 weeks
- Proceed with cardioversion
- If NOT adequately anticoagulated
- Initiate DOAC / VKA / LMWH / UFH
- After cardioversion
- Start short-term OAC for all patients - (regardless of baseline stroke risk)
(Consider TEE-guided strategy if available)
Shock-refractory AF
AF that remains incessant despite ~3 maximum-energy synchronised shocks
Optimising shock success
- Improve pad–skin contact
- Apply firm pad pressure
- Reposition pads to alter the shock vector
- Consider antiarrhythmic drugs to reduce defibrillation threshold
- Consider double synchronised cardioversion
The benefit of double-sequence cardioversion remains uncertain and should be considered only after standard optimisation steps.
Step 3: Stable AF — Now what?
Now that we’ve moved past electrical cardioversion, there are two paths:
1️⃣ Rate control
2️⃣ Rhythm control
- No mortality benefit of rhythm control over rate control
- No quality-of-life advantage with rhythm control
- Stroke rates were similar, despite more sinus rhythm in the rhythm group
(Patients unable to tolerate AF were largely excluded)
- Studied patients with mild to moderate heart failure
- Rate control is not inferior to rhythm control for major outcomes
Recent guidelines (ESC and AHA) recommend rate control as the initial strategy in most patients with atrial fibrillation.
Rate control target: Heart rate <100–110 bpm.
The real deciding question here is :
Is there decompensated heart failure?
If NO → Consider Rate control options
First-line
- β-blockers -Metoprolol, Esmolol
- Non-DHP CCB - Diltiazem, Verapamil
- Contraindicated if EF < 40%
Both β-blockers and non-DHP CCBs are effective for ventricular rate control
High-quality data suggest diltiazem may achieve faster and better rate control than metoprolol
Second-line
- Digoxin
- Use only if β-blockers and non-DHP CCBs are contraindicated or ineffective
- Can be considered alone or in combination with other drugs.
If monotherapy fails
If symptoms persist and are thought to be due to poor ventricular rate control
consider combination therapy with any two of the following:
- β-blocker
- Non-DHP CCB
- Digoxin
(As per NICE guidance)
Use Non-DHP-CCBs only if EF >40%
Adjunct therapy: IV Magnesium
Adding magnesium to standard rate-control therapy is reasonable to help achieve and maintain ventricular rate control in atrial fibrillation.
- Improves AV nodal refractoriness
- Enhances response to β-blockers and CCBs
- Dose: 2–4.5 g IV
LOMAGHI Trial
Intravenous Magnesium appears to have a synergistic effect when combined with other AV nodal blockers, resulting in improved rate control. Similar efficacy was observed with 4.5 g and 9 g of Magnesium, but the 9 g dose was associated with more side effects.
If YES → Amiodarone
- 150–300 mg IV over 1 hour
- Then 10–50 mg/h infusion over 24 hours
QRS > 200 ms: Think pre-excitation / WPW
- DO NOT give AV nodal blockers
They may precipitate ventricular fibrillation
- Consider: Synchronized DC cardioversion /Procainamide
(often not available in India)
Still considering Rhythm Control?
Most stable AF patients do not need rhythm control in the ED.
Why consider rhythm control?
- Restoration of sinus rhythm can
- Reduce symptoms
- Improve LV function
Who can you offer rhythm control to?
- AF onset < 24 hours
(ESC Guidelines 2024; Often difficult to prove in the ED)
- Adequately anticoagulated for ≥ 3 weeks
If not anticoagulated, start DOAC / VKA / LMWH / UFH before cardioversion if time allows
Pharmacologic rhythm control options
- Amiodarone
- Drug of choice in: HFrEF, LVH, CAD, Other structural heart disease
- Expect conversion: Often 8–12 hours, not immediate
- There are other options not available in India
- Flecainide / Propafenone (IV) - Recommended for recent-onset AF
- Vernakalant
DO NOT offer pharmacologic cardioversion if QTc > 500 ms
For quick ED reference: Drug doses
Rate Control Drugs
β-blockers
Metoprolol
- 2.5–5 mg IV over 2 minutes
- May repeat every 5 minutes
- Maximum: 3 doses
Esmolol
- 500 μg/kg IV bolus over 1 minute
- Then 50–300 μg/kg/min infusion
Non-DHP CCBs
Diltiazem
- 0.25 mg/kg IV over 2 minutes
- Repeat 0.35 mg/kg if needed
- Maintenance: 5–15 mg/h infusion
Verapamil
- 5–10 mg IV over ≥2 minutes
- May repeat up to 2 doses
- Maintenance: 5 mg/h infusion (max 20 mg/h)
Digoxin
- 0.25–0.5 mg IV loading dose
- Then 0.25 mg IV every 6 hours
- Maximum: 1.5 mg in 24 hours
Amiodarone
- 150–300 mg IV over 1 hour
- Then 10–50 mg/h infusion over 24 hours
Magnesium
- 2–4.5 g IV over 20 minutes
Rhythm Control Drugs
Amiodarone
- 300 mg IV over 30–60 min
- Then 900–1200 mg IV over 24 h
What matters…
The questions you should ask before you decide on what to do with the AF
1️⃣ Is the patient Unstable?
Look for CHAAS
- C – Chest pain (ischemic)
- H – Hypotension
- A – Altered mental status
- A – Acute heart failure
- S – Signs of shock
If your patient is unstable
- Immediate management : Synchronized DC cardioversion
- Initial energy : 200 J biphasic
- Escalate the energy in case of shock failure
- If NOT adequately anticoagulated : Initiate anti coagulation
- Consider amiodarone infusion.
2️⃣ Is there decompensated heart failure?
If YES → Amiodarone
- 150–300 mg IV over 1 hour
- Then 10–50 mg/h infusion over 24 hours
3️⃣Is the EF > 40% ?
- If NO → β-blocker
- If YES → Non DHP-CCB / β-blocker
- If there are any Contraindications to BB/CCB → Digoxin
- Adjunct → IV Magnessium
Want to Read More?
- Joglar, José A., et al. "2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines." Journal of the American College of Cardiology 83.1 (2024): 109-279.
- Van Gelder, Isabelle C., et al. "2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS) Developed by the task force for the management of atrial fibrillation of the European Society of Cardiology (ESC), with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC. Endorsed by the European Stroke Organisation (ESO)." European heart journal (2024): ehae176.
- Senoo, Keitaro, Yee Cheng Lau, and Gregory YH Lip. "Updated NICE guideline: management of atrial fibrillation (2014)." Expert review of cardiovascular therapy 12.9 (2014): 1037-1040.
- Wigginton, Jane G., et al. "Part 9: adult advanced life support: 2025 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care." Circulation 152.16_suppl_2 (2025): S538-S577.
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