Sources: 2023 ACC/AHA/ACCP/HRS AF Guideline · AHA ACLS 2025 · UHN ED AFib Protocol · Long B et al. AJEM 2023 · Ko D et al. JAMA 2025
AF / Flutter — ED Tool
Emergency department clinical decision support
Medical-legal disclaimer
This tool is intended as a clinical decision support aid only. It does not replace the clinical judgment of a licensed physician, the physical examination of the patient, or current institutional protocols.
All management decisions — including drug selection, dosing, cardioversion, anticoagulation, and disposition — remain the sole responsibility of the treating clinician. Patient-specific factors not captured by this tool may materially alter the appropriate course of action.
Drug doses listed are standard adult doses and must be adjusted for individual patient factors including weight, renal function, hepatic function, comorbidities, and concurrent medications.
This tool does not constitute medical advice and creates no physician-patient relationship. Information is based on published guidelines current as of 2025 and is subject to change as evidence evolves.
Developed for educational and clinical support use.
Sources: 2023 ACC/AHA/ACCP/HRS AF Guideline · AHA ACLS 2025 · UHN ED AFib Protocol · Long B et al. AJEM 2023 · Ko D et al. JAMA 2025
You will not be shown this screen again this session
Initial investigations — order now
Order these before or in parallel with management
These should not delay cardioversion in an unstable patient. For stable patients, results guide management decisions.
Always order
12-lead ECG
Confirm AF or flutter · rate · QRS width · pre-excitation (WPW) · ischemia · QTc
CBC (complete blood count)
Exclude anemia as precipitant · baseline Hgb before anticoagulation
Basic metabolic panel (BMP)
Electrolytes (K⁺, Mg²⁺) — hypokalemia and hypomagnesemia increase arrhythmia risk and affect cardioversion safety · renal function for OAC dosing (CrCl)
Serum creatinine + eGFR
Required for DOAC dose selection and for calculating CrCl
TSH (thyroid function)
Thyrotoxicosis is a common reversible precipitant of AF — must be excluded, especially in new-onset AF
Cardiac monitoring (continuous)
Rate trending · detect conversion to sinus or deterioration · essential during cardioversion and rate-control drug administration
Order if clinically indicated
Troponin
If chest pain, dyspnea, or new ischemic ECG changes — ACS can precipitate or result from AF with rapid ventricular response
BNP or NT-proBNP
Suspected new heart failure or acute decompensation — helps differentiate AF-related HF from primary HF
D-dimer / CT-PA
If clinical suspicion for pulmonary embolism as precipitant (tachycardia disproportionate to AF, hypoxia, pleuritic pain, recent surgery or immobility)
Coagulation (INR, aPTT)
If patient on warfarin — INR determines if adequately anticoagulated for cardioversion · assess if INR < 2 before proceeding
Digoxin level
If patient on digoxin — toxicity can cause AF and contraindicates cardioversion
Blood cultures / infection workup
If sepsis or active infection suspected as AF precipitant — treat the underlying cause
Portable CXR
Suspected pulmonary cause, decompensated HF, or first-episode AF — assess cardiac size, pulmonary congestion, pneumonia
For cardioversion planning
Echocardiogram (if available)
New-onset AF — assess LV function (EF), valvular disease, left atrial size. Not required before urgent cardioversion but informs long-term management.
TEE (transesophageal echocardiogram)
AF > 48 hrs and not adequately anticoagulated — to exclude left atrial appendage thrombus before cardioversion. Cardiology input required.
Start a new case?
This will clear all data for the current case — rhythm assessment, CHADS score, bleeding risk, OAC decision, and the case summary.
Step 1 of 3 · Hemodynamic status
Is the patient hemodynamically unstable?
Hypotension · Acute CHF · Altered LOC · New ischemic ECG changes
Unstable — immediate action required
Duration of AF?
Step 2 of 3 · Ventricular rate
What is the ventricular rate?
Step 3 · Duration & anticoagulation
AF type and duration?
Step 3 · Duration & anticoagulation
AF type and duration?
HR > 200 or wide QRS — urgent cardioversion
Synchronized cardioversion 150–200J biphasic.
If duration > 48 hrs, consider TEE-guided approach if available.
Refer to cardiology. Proceed to stroke prevention.
Outcome & next steps
What was the result of cardioversion / rhythm control?
Select the outcome to see disposition and next management steps
Case summary — dictation & documentation
No case in progress
Work through a patient case first — start with Rate & rhythm decision, then Stroke prevention, then Outcome & disposition.
Documentation ready
Fill in any missing fields, then copy the dictation note at the bottom.
Complete any details not captured automatically
Rhythm type
Cardioversion method used
OAC prescribed
Always verify against the patient chart before using for formal documentation.
Stroke prevention — all AF/flutter patients
Step 1 — valvular disease?
Mitral stenosis or prosthetic heart valve present?
Valvular AF — warfarin strongly recommended
DOACs are not indicated for valvular AF with significant mitral stenosis or mechanical prosthetic valves.
Warfarin — target INR 2–3.
Assess bleeding risk before starting. Refer cardiology.
Anticoagulation dosing reference
Vitamin K antagonist · Target INR 2–3
Dosing: 5 mg PO daily × 5 days, then reassess INR Take: same time each day, with or without food Monitoring: INR check at day 5–7, then as needed Interactions: many — antibiotics, NSAIDs, amiodarone, and diet all affect INR
Avoid DOACs here: Valvular AF with significant mitral stenosis or mechanical prosthetic valve — DOACs not indicated
CHA₂DS₂-VASc score
Tap each risk factor present
CHA₂DS₂-VASc score0
Bleeding risk — tap all that apply
Check each bleeding risk factor present in this patient
No risk factors identified
OAC agent selection
Choose based on patient age, renal function, and preferences. If on ASA, discontinue unless separate clear indication exists. Advise pharmacist review at discharge.
CrCl formula: (140 − age) × wt kg × 1.23 (× 0.85 if female) ÷ serum Cr µmol/L
Standard dose — no special criteria
Direct thrombin inhibitor
Take: with or without food. Swallow whole — do not crush. Timing: BID, approximately 12 hrs apart
Avoid if: CrCl < 30 mL/min · Active major bleed · Mechanical heart valve
Caution: Dyspepsia common — take with food if needed. P-gp inhibitors (e.g. dronedarone, ketoconazole) raise levels.
Factor Xa inhibitor
Take: with main meal — food required for adequate absorption Timing: once daily with evening meal preferred
Avoid if: CrCl < 15 mL/min · Active major bleed · Mechanical heart valve
Take: with or without food Timing: BID, approximately 12 hrs apart
Avoid if: CrCl < 15 mL/min · Active major bleed · Mechanical heart valve
Dose-reduce to 2.5 mg BID if ≥ 2 of: age ≥ 80, weight ≤ 60 kg, serum Cr ≥ 133 µmol/L
Reduced dose — age > 80, bleeding risk, or CrCl 30–50 mL/min
Direct thrombin inhibitor — reduced dose
Preferred for: age > 80, bleeding risk, or CrCl 30–50 mL/min Take: with or without food. Swallow whole.
Avoid if: CrCl < 30 mL/min
Factor Xa inhibitor — reduced dose
Preferred for: CrCl 15–50 mL/min or bleeding risk Take: with main meal
Avoid if: CrCl < 15 mL/min
Factor Xa inhibitor — reduced dose
Use when ≥ 2 of: age ≥ 80, weight ≤ 60 kg, serum Cr ≥ 133 µmol/L Take: with or without food
Avoid if: CrCl < 15 mL/min
Severe renal impairment — CrCl < 30 mL/min
Vitamin K antagonist — preferred in severe renal impairment
Dosing: 5 mg PO daily × 5 days, then reassess INR Target INR: 2–3
DOACs generally avoided when CrCl < 30 mL/min
Caution: Many drug and dietary interactions. Regular INR monitoring required.
Rate control agents — most used first
Metoprolol
1st line
Cardioselective beta-1 blocker
IV dosing
Dose: 5 mg IV over 2–5 min Repeat: × 2 additional doses q5 min (max 15 mg IV total)
Monitor HR and BP after each dose
Oral maintenance
Metoprolol tartrate 12.5–25 mg PO BID (range 25–150 mg BID)
Metoprolol succinate XL 25–50 mg PO daily if preferred
Avoid: Cardiogenic shock · Decompensated HF · Severe bradycardia or high-degree AV block without pacemaker · Pre-excitation AF (WPW) · Severe asthma or active bronchospasm
Caution: LV dysfunction — use low dose, monitor closely · Mild-moderate reactive airway disease (generally safe at low dose) · Concurrent diltiazem or verapamil
Preferred in AF with concurrent ACS — reduces ischemia and controls rate
Diltiazem
1st line
Non-dihydropyridine calcium channel blocker
IV dosing
1st dose: 0.25 mg/kg IV (max 20 mg) over 2–10 min Repeat if needed: 0.35 mg/kg IV (max 25 mg) over 2–10 min, 15 min after 1st dose Infusion: 5–15 mg/hr IV titrated to HR
Oral maintenance (once rate controlled)
Diltiazem CD 120 mg PO daily (range 120–360 mg/day)
Avoid: LV systolic dysfunction (EF < 40%) · Decompensated HF · Pre-excitation AF (WPW) · Cardiogenic shock · Sick sinus syndrome without pacemaker · 2nd or 3rd degree AV block without pacemaker
Caution: Hypotension · Concurrent beta-blocker (risk of high-degree block) · Severe hepatic impairment
Digoxin
LV dysfunction / add-on
Cardiac glycoside — AV nodal blocker
IV loading
Load: 0.5 mg IV bolus, then 0.25 mg IV q6h × 2 additional doses
Total load: up to 1 mg IV
Reduce to 0.75 mg total if renal impairment
Stop immediately if toxicity (nausea, visual changes, bradycardia, new arrhythmia) Full effect may take up to 6 hours
Oral maintenance
0.125–0.25 mg PO daily (renally adjusted)
Avoid: Pre-excitation with AF (WPW) — can accelerate accessory pathway conduction and cause VF · Active digoxin toxicity · Ventricular fibrillation
Caution: Renal impairment — reduce dose and monitor levels · Hypokalemia and hypomagnesemia increase toxicity risk · Elderly — high sensitivity · Drug interactions: amiodarone, verapamil, quinidine all raise digoxin levels
Preferred when LV dysfunction is present and beta-blockers or CCBs are not tolerated. Useful as add-on for additional rate control.
Verapamil
2nd line
Non-dihydropyridine CCB — second-line option
IV dosing
Dose: 5–10 mg IV over 2 min
May repeat 10 mg after 30 min if no response
Generally less preferred than diltiazem — greater negative inotropy
Avoid: LV dysfunction or HF · Cardiogenic shock · WPW with AF · High-degree AV block · Concurrent IV beta-blocker (risk of severe bradycardia or asystole)
Note: Non-dihydropyridine CCBs (diltiazem, verapamil) are potentially harmful if EF < 40%
Cardioversion — most used first
Electrical — synchronized DC cardioversion
1st line
Energy and technique
AF: 150–200J biphasic (200J monophasic reduces need for repeat shock) Flutter: lower joules usually sufficient — 50–100J
Success rate: 80–90% in both AF and flutter
Duration > 48 hrs → consider TEE to exclude LA thrombus before cardioversion
Relative contraindications: Digitalis toxicity (may trigger refractory VF) · Uncorrected hypokalemia or hypomagnesemia — correct electrolytes first · If pacemaker or ICD present: place pads ≥ 8 cm from device
Chemical cardioversion — procainamide
Alternative / adjunct
Dosing
Dose: 15–17 mg/kg IV (usual 1 g) in 250 mL D5W or NS over 60 minutes
Converts AF to sinus in 50–60% · 18% in flutter
Can be safely combined with electrical cardioversion Slow or stop if QRS widens > 50% or hypotension develops
Avoid: Pre-existing QT prolongation · History of torsades de pointes · Severe HF or cardiogenic shock · Myasthenia gravis · Active lupus · Concurrent QT-prolonging drugs
Caution: Renal impairment — active metabolite NAPA accumulates · Monitor ECG continuously during infusion
Pre-cardioversion anticoagulation (CCS guideline):
AF < 48 hrs + high stroke risk (rheumatic HD, mitral stenosis, prosthetic valve, prior TIA/stroke) AND not anticoagulated or INR < 2 → Enoxaparin 1 mg/kg SC or UFH IV before cardioversion.
AF > 48 hrs / unknown + not anticoagulated or INR < 2 → anticoagulate before cardioversion.
Antiarrhythmic drugs — rhythm control — most used first
Amiodarone
Most used in ED
Class III antiarrhythmic — rate and rhythm effects
IV dosing (acute setting)
Loading bolus: 150 mg IV over 10 min Infusion: 1 mg/min × 6 hrs, then 0.5 mg/min × 18 hrs Breakthrough: additional 150 mg IV over 10 min
Max IV dose in 24 hrs: 2.2 g
Oral maintenance
400 mg PO TID × 7–10 days (load), then 200 mg PO daily
Avoid: Severe sinus node dysfunction without pacemaker · High-degree AV block without pacemaker · Severe pulmonary disease (relative) · Known hypersensitivity to iodine
Caution: Long half-life — cumulative toxicities: pulmonary toxicity, thyroid dysfunction, hepatic toxicity, corneal deposits. Monitor TFTs, LFTs, CXR regularly. Drug interactions: raises INR with warfarin, raises digoxin levels, interacts with statins.
Safe to use in LV dysfunction and structural heart disease — preferred AAD when EF is reduced
Flecainide
Normal EF only
Class IC antiarrhythmic
Dosing
IV: 2 mg/kg over 10 min (max 150 mg) Oral pill-in-pocket: 200–300 mg PO single dose Oral maintenance: 50–150 mg PO BID
Avoid: Any structural heart disease · Prior MI or significant CAD · LV dysfunction (EF ≤ 40%) · HF · Bundle branch block or significant conduction disease · CrCl < 35 mL/min
Use only in structurally normal hearts with preserved EF
Propafenone
Normal EF only
Class IC antiarrhythmic (also mild beta-blocker activity)
Dosing
Oral pill-in-pocket: 450–600 mg PO single dose Oral maintenance: 150–300 mg PO TID or 225–425 mg SR BID
Avoid: Structural heart disease · Prior MI · LV dysfunction · HF · Asthma or bronchospasm · Cardiogenic shock · Significant AV or bundle branch block
Sotalol
Class III antiarrhythmic + non-selective beta-blocker
Dosing
Oral: 80 mg PO BID, increase to 120–160 mg BID if needed
Requires in-hospital initiation with QT monitoring × minimum 3 days
Avoid: QTc > 450 ms at baseline · CrCl < 40 mL/min · HR < 50 bpm · Hypokalemia or hypomagnesemia · Severe asthma · Decompensated HF
Torsades risk: Increases with dose, renal impairment, and electrolyte abnormalities. Never initiate as outpatient without QT monitoring.
Dronedarone
Class III antiarrhythmic (non-iodinated amiodarone analogue)
Dosing
400 mg PO BID with meals
Avoid: NYHA Class III–IV HF or EF < 35% (increases mortality) · Permanent AF · Severe hepatic impairment · QTc > 500 ms · Strong CYP3A4 inhibitors (e.g. ketoconazole, clarithromycin)
Reasonable in paroxysmal/persistent AF with normal or mildly reduced EF and no HF symptoms
Dofetilide
Class III antiarrhythmic — potassium channel blocker
Dosing
125–500 mcg PO BID (renally adjusted)
Requires in-hospital QT monitoring × minimum 3 days — not typically started in ED
Avoid: QTc > 440 ms (or > 500 ms with bundle branch block) · CrCl < 20 mL/min · Hypokalemia · Concurrent QT-prolonging drugs · Severe hepatic impairment
Rate control target
Target HR: 60–110 bpm + symptom control.
Optimize current agent dose before switching. If cardioversion is the first approach, avoid rate-control agents as they may reduce cardioversion success.
Rate vs rhythm — who benefits
Rhythm control
Younger · Short AF history · HFrEF · Moderate-severe symptoms · More LV dysfunction
Rate control
Older · Long AF history · Low symptoms · Less LV dysfunction
Quick reference
Unstable patient
Immediate synchronized cardioversion 150–200J biphasic regardless of duration. If > 48 hrs and time allows: judicious rate control first. Proceed to stroke prevention. Refer cardiology.
Stable · HR ≤ 110 or 110–200
≤ 48 hrs or adequately anticoagulated → rhythm or rate control (shared decision)
> 48 hrs, not anticoagulated → rate control first. No cardioversion without anticoagulation unless TEE excludes LA thrombus.
Permanent AF → rate control only.
Stroke prevention
Valvular AF → warfarin only. DOACs not indicated.
Score 0 (men) → no OAC needed
Score 1 men / 2 women → consider OAC
Score ≥ 2 men / ≥ 3 women → OAC recommended
Prefer DOACs over warfarin in non-valvular AF.
Aspirin alone is harmful when OAC is indicated.
Pre-cardioversion anticoagulation
AF < 48 hrs + high stroke risk + not anticoagulated → Enoxaparin 1 mg/kg SC or UFH before cardioversion.
AF > 48 hrs / unknown + not anticoagulated → anticoagulate first.
Discharge
Unless admission required for secondary diagnosis, most stable AF patients may be discharged home with referral to AF-QCP for outpatient management.
Annual update · recent advances
Recent advances in AF / flutter management
Synthesized from 2023–2025 guidelines and peer-reviewed literature
1
Early rhythm control — a shift in strategy
The traditional view that rate control and rhythm control produce equivalent outcomes has been revised. The EAST-AFNET 4 trial (2020) and subsequent guideline updates through 2023 show that early rhythm control — initiated within one year of AF diagnosis — reduces the composite of cardiovascular death, stroke, and hospitalization compared to rate control alone, particularly in patients with cardiovascular risk factors. This has moved rhythm control from a symptom-driven option to a strategy that may modify disease progression. The 2023 ACC/AHA/ACCP/HRS guideline now classifies early rhythm control as reasonable (Class IIa) in eligible patients regardless of symptom burden.
Ko D et al. JAMA 2025 · 2023 ACC/AHA/ACCP/HRS AF Guideline (Joglar JA et al.)
2
Catheter ablation — earlier and broader use
Pulmonary vein isolation by catheter ablation is now supported as first-line rhythm control in symptomatic paroxysmal AF (Class I), not merely a rescue after AAD failure. For patients with AF and heart failure with reduced ejection fraction, ablation has shown superiority over AADs in reducing mortality and HF hospitalizations (CASTLE-AF trial). The 2023 guideline also supports ablation earlier in the disease course to prevent atrial remodeling. In the ED, this changes the conversation: patients presenting with new-onset AF should be informed that curative options exist and referred appropriately rather than simply started on lifelong AADs.
2023 ACC/AHA/ACCP/HRS AF Guideline · Ko D et al. JAMA 2025 · Holder S, Amin P. Am Fam Physician 2024
3
Staging AF — a new clinical framework
The 2023 ACC/AHA guideline introduced a formal staging system for AF. Stage 1 is at-risk (modifiable risk factors present, no AF yet). Stage 2 is pre-AF (atrial pathology detected — left atrial enlargement, frequent ectopy — but no diagnosed AF). Stage 3 is clinically diagnosed AF. Stage 4 is permanent AF. This framework shifts AF management from reactive to preventive, emphasizing lifestyle and risk factor modification (LRFM) at every stage. For ED physicians, identifying Stage 2 patients — those with atrial high-rate episodes on wearables or monitors — now carries clinical significance, particularly around anticoagulation decisions when episodes last ≥ 24 hours and CHA₂DS₂-VASc ≥ 2.
2023 ACC/AHA/ACCP/HRS AF Guideline (Joglar JA et al.) · Ko D et al. JAMA 2025
4
ED cardioversion — expanded safety data and protocols
Recent emergency medicine literature (Long B et al., AJEM 2023) confirms that ED cardioversion for AF with onset ≤ 48 hours is safe and effective, with electrical cardioversion achieving sinus rhythm in 80–92% of attempts. Chemical cardioversion with procainamide (50–60% conversion rate) is a practical first-line option before electrical cardioversion, and the two can be combined safely. A key update is that monophasic 200J has been shown to reduce the need for repeat shocks compared to lower biphasic energy. The AHA 2025 ACLS update reinforces synchronized cardioversion as the primary intervention for unstable AF, with renewed emphasis on minimizing delays — sedation and defibrillation in parallel, not sequential.
Long B, Brady WJ, Gottlieb M. AJEM 2023 · AHA ACLS Guidelines 2025 (Wigginton JG et al.)
5
AF in acute hospitalization — a separate clinical entity
The 2023 AHA Scientific Statement on AF during acute hospitalization establishes that new-onset AF occurring in the context of surgery, sepsis, or critical illness is not equivalent to primary AF and carries distinct management implications. These patients have high in-hospital stroke risk but may not need long-term anticoagulation. Current evidence does not support routine long-term OAC after isolated hospital-acquired AF in the absence of other risk factors, though anticoagulation during the acute episode is still indicated based on clinical stroke risk. This distinction matters in the ED when evaluating patients who develop AF after a procedure or during an acute illness.
Chyou JY et al. AHA Scientific Statement. Circulation 2023
6
DOACs — further consolidation over warfarin
The 2023–2025 guidelines further solidify the preference for DOACs over warfarin in non-valvular AF. Apixaban, rivaroxaban, and dabigatran all show equivalent or superior efficacy with lower intracranial hemorrhage rates. The updated guidance specifies that even in elderly patients and those with moderate renal impairment, dose-adjusted DOACs are preferred where feasible. Warfarin remains the only option for valvular AF with moderate-to-severe mitral stenosis or mechanical prosthetic valves — the evidence does not support DOACs in these patients. In the ED, the practical implication is to start a DOAC before discharge rather than bridging with heparin in most non-valvular cases.
2023 ACC/AHA/ACCP/HRS AF Guideline · Holder S, Amin P. Am Fam Physician 2024
7
Lifestyle and risk factor modification — now a formal treatment
LRFM is no longer simply background advice. The 2023 guideline elevates it to a recommended treatment at every stage of AF (Class I). The evidence base for specific interventions has grown substantially: weight loss of ≥ 10% in obese patients reduces AF burden and recurrence after ablation. Blood pressure control below 130/80 mmHg reduces incident AF. Alcohol reduction — even from moderate intake — decreases AF episodes (HOLIDAY HEART data, updated). Treatment of obstructive sleep apnea improves rhythm control outcomes. In the ED, this means incorporating a brief LRFM discussion and printed resources into every AF discharge, not just referring the patient back to their family physician.
2023 ACC/AHA/ACCP/HRS AF Guideline · Ko D et al. JAMA 2025 · Holder S, Amin P. Am Fam Physician 2024
Full references
1
Joglar JA, Chung MK, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation. J Am Coll Cardiol. 2024. PMC11104284 ↗
2
Wigginton JG, Agarwal S, Bartos JA, et al. Part 9: Adult Advanced Life Support: 2025 AHA Guidelines for CPR and Emergency Cardiovascular Care. Circulation. 2025. Full text ↗
3
Chyou JY, Barkoudah E, Dukes JW, et al. Atrial Fibrillation Occurring During Acute Hospitalization: A Scientific Statement From the AHA. Circulation. 2023. Full text ↗
4
Holder S, Amin P. Atrial Fibrillation: Common Questions and Answers About Diagnosis and Treatment. Am Fam Physician. 2024. PubMed ↗
5
Long B, Brady WJ, Gottlieb M. Emergency Medicine Updates: Atrial Fibrillation With Rapid Ventricular Response. Am J Emerg Med. 2023. PubMed ↗
6
Ko D, Chung MK, Evans PT, Benjamin EJ, Helm RH. Atrial Fibrillation: A Review. JAMA. 2025. Full text ↗
This summary reflects guideline-level evidence available through early 2025. Clinical judgment and local protocols always take precedence. This tool does not replace consultation with cardiology for complex presentations.