Atrial Fibrillation

CFPC Key Features

  1. In a patient who presents with new onset atrial fibrillation, look for an underlying cause (e.g., ischemic heart disease, acute myocardial infarction, congestive heart failure, cardiomyopathy, pulmonary embolus, hyperthyroidism, alcohol, etc.)

  2. In a patient presenting with atrial fibrillation,

    1. Look for hemodynamic instability,

    2. Intervene rapidly and appropriately to stabilize the patient.

  3. In an individual presenting with chronic or paroxysmal atrial fibrillation,

    1. Explore the need for anticoagulation based on the risk of stroke with the patient,

    2. Periodically reassess the need for anticoagulation.

  4. In patients with atrial fibrillation, when the decision has been made to use anticoagulation, institute the appropriate therapy and patient education, with a comprehensive follow-up plan.

  5. In a stable patient with atrial fibrillation, identify the need for rate control.

  6. In a stable patient with atrial fibrillation, arrange for rhythm correction when appropriate.

General Overview


  • First symptomatic attack, and first objective confirmation

  • Duration and frequency of episodes

  • Symptoms related to AF

    • Palpitations, tachycardia, angina, dyspnea

    • Fatigue, weakness, dizziness, lightheadedness, reduced exercise capacity, presyncope

    • Increased urination (due to the release of atrial natriuretic peptide)

    • Right-sided heart failure (peripheral edema, weight gain, ascites)

    • Embolic event

  • Symptom severity and impact on quality of life

  • Review

    • Causes, risk factors, family history

    • Previous visits, hospitalizations, interventions, efficacy, tolerance, adverse effects


  • Cardiac

    • Hypertension (1.4 x risk)

    • Coronary heart disease (ischemia/MI)

    • Valvular heart disease (including rheumatic heart disease)

    • Heart failure

    • Cardiomyopathy (hypertrophic, dilated, restrictive)

    • Congenital heart disease (ASD)

    • Venous thromboembolic disease (DVT/PE - likely due to right atrial strain from resistance/afterload)

    • Myocarditis/Pericarditis

  • Pulmonary

    • COPD

    • OSA

  • Metabolic

    • Hyperthyroidism (including subclinical hyperthyroidism)

    • Obesity

    • Diabetes (1.5 x risk)

    • Metabolic syndrome (hypertension, obesity, diabetes, and dyslipidemia)

  • Chronic Kidney disease

  • Other

    • Age

    • Alcohol (heavy alcohol use in men - holiday heart syndrome), note: no evidence that caffeine can provoke arrhythmias

    • Stroke/TIA

    • Family history

    • Inflammation/infection

    • Medications: Beta-agonists (norepi, epi, dobutamine), theophylline, adenosine

    • Surgery (highest in cardiac surgery)


Clinical Pattern

  • New-onset

  • Paroxysmal: Continuous AF episode longer than 30 seconds but terminates spontaneously or with intervention within 7 days of onset (episodes may recur)

  • Persistent: Continuous AF sustained >7 days

    • “Long-standing” persistent: ≥ 12 months

  • Permanent: Joint decision by patient and clinician to cease further attempts to restore/maintain sinus rhythm


  • Primary

  • Secondary

    • Reversible: Secondary to acute illness, limited future risk of AF

      • eg. Hyperthyroidism or alcohol intoxication in absence of risk factors

    • Provoked: Patients with significant underlying risks, 'unmasked' by acute illness, oingoing risk for AF

      • eg. AF after mitral valve surgery in context of COPD exacerbation

Valvular vs. nonvalvular

  • Nonvalvular: AF in the absence of any mechanical valve or moderate-to-severe (rheumatic/non rheumatic) mitral stenosis


  • EKG (r/o MI, pre-excitation, conduction disturbances)

  • Transthoracic Echocardiogram (structural/valvular heart disease, function, atrial enlargement)

    • Transesophageal Echocardiogram (TEE) for LA thrombi to guide cardioversion

  • Labs:

    • CBC

    • Serum Na, K, Calcium, Magnesium

    • Serum Creatinine/eGFR

    • TSH

    • LFT

    • A1C, Lipids (risk stratification, can be done as outpatient)

    • INR (baseline)

  • Other

    • Holter monitoring/exercise testing to evaluate rate control

    • CXR if pulmonary disease or heart failure suspected

    • BNP or N-terminal pro-BNP may be elevated in paroxysmal and persistent AF in the absence of clinical heart failure (and decrease in sinus)

    • Electrophysiological Study if AF due to SVT where ablation may be helpful to prevent/reduce recurrences of AF (suspect pre-excitation when delta wave on EKG)

    • Troponin if suspect ischemia/infarction

    • Sleep study if suspect obstructive sleep apnea

Acute Treatment

Acute Management of Unstable AF

  • Always ABCs!

  • Unstable if Hypotension or ACS or pulmonary edema (heart failure)

    • Consider other causes of hypotension if HR<130 (MI, PE, sepsis, hypovolemia)

  • Urgent Electrical DC cardioversion (AP pads, 200J synchronized) if hemodynamic instability (especially if >150) or if rate control not effective

  • Manage hypotension

    • Fluids (care for pulmonary edema)

    • Vasopressors

Acute Management of Stable AF

  • Treat underlying/reversible causes

    • Review medications

    • Avoid beta-adrenergic vasopressors (epi/norepi/dobutamine), consider using phenylephrine instead

    • Optimize volume status

    • Treat pain, anxiety, withdrawal

    • Treat electrolyte abnormalities (potassium, magnesium)

      • Consider empiric magnesium 2-4g IV if magnesium levels not available

    • Treat hypoxemia or respiratory distress (CPAP/BiPAP/HFNC)

    • r/o sepsis, PE, thyrotoxicosis, etc…

  • r/o WPW or pre-excitation syndrome (bizarre QRS change in width beat to beat and HR >220)

    • If WPW, do NOT start AV node slowing medications (Amiodarone, BB, CCB), consider only electrical cardioversion

  • Rate vs. Rhythm

    • Consider Acute Rate-Control

      • Asymptomatic

      • Chronic AF (eg. >1y diagnosed AF)

      • Onset AF>48h and not anticoagulated (risk of thrombus)

      • Medication choice depending on LV function:

        • LVEF40%:

          • Beta-blockers

            • Metoprolol IV 5mg q5mins x 3 PRN (max 15mg)

              • Convert to PO with a 1:2.5 (IV:PO) ratio, start 30mins after effective IV rate control

            • Esmolol IV

  • ND-CCBs

    • Diltiazem 15-25mg IV bolus (0.25mg/kg) x1, can repeat q15 mins once, then infusion at 2.5-15mg/h (consider reduce dose after target heart rate reached as diltiazem can accumulate)

        • LVEF<40%:

          • B-blockers

          • Severe heart failure and longstanding AF: Digoxin 0.25mg IV x1

          • Borderline hemodynamic instability: Amiodarone

    • Consider Acute Rhythm-Control if

      • Highly symptomatic (especially if symptomatic despite adequate rate control)

      • Risk of hemodynamic instability (heart failure, pulmonary hypertension, mitral stenosis)

      • Newly diagnosed AF (within 1 year)

      • Low risk (NVAF<12h with no recent stroke/TIA, or <48h with CHADS2<2) or if on OAC3w

      • Atrial Flutter

      • Associated with reduced CV deaths and rates of stroke

    • Choice DCCV vs pharmacological depending on situation:

      • Electrical more effective (150J biphasic, or greater)

        • Ideal if unknown medical history

        • Consider paddles with force in obese patients

        • Consider preparation of atropine and pacing in the event of prolonged sinus pause

        • Consider second trained operator managing sedation and airway

      • Pharmacological ideal on non-fasting patient and does not require procedural sedation

        • AVOID if hypotension, ischemic heart disease, heart failure, conduction system disease/significant structural heart disease, and Brugada syndrome.

        • Procainamide 1g (or 15-18 mg/kg) IV over 60 min

          • Time to conversion 60 minutes, avoid in Brugada

        • Amiodarone 150-300mg IV bolus then infusion at 1mg/min, can repeat bolus x1

        • OAC x 4w, then as per CHADS65

  • Need for hospital admission?

    • YES if highly symptomatic with acute medical illness/complex medical conditions, inability to achieve rate control, or require monitoring/testing not available as outpatient

  • Need for OAC?

    • Short-term OAC x 4 weeks after cardioversion

    • Long-term OAC if CHADS65, see Anticoagulation section below

  • Follow-up, ideally early within one week (lower risks of morbidity/mortality)


Longterm Rate Control

    • AVOID if pre-excitation syndrome

    • Target resting HR<100bpm, if

      1. CHF: BB preferred+/- Digoxin

      2. CAD: BB preferred

      3. No CHF/CAD: CCB preferred if no compelling indication for BB, Digoxin or combo

      4. HTN or reactive airway disease: CCB

    • Beta-blockers as initial therapy in MI or LV systolic dysfunction:

      • Bisoprolol 2.5mg PO daily (target 10mg PO daily)

        • Preferred if LV dysfunction

      • Metoprolol 12.5-25mg PO BID (target 100-200mg PO BID)

        • Preferred if CAD, HTN

      • Carvedilol 6.25mg BID (target 25 mg BID)

        • Preferred if LV dysfunction

    • Non-dihydropyridine CCB:

      • Diltiazem extended release 120-360mg PO daily

      • Verapamil extended release 180-480 mg PO daily or immediate release divided TID-QID

      • Digoxin 0.0625-0.25mg PO daily (max trough 1.2mcg/mL) in selected older/sedentary individuals with HF and for those with inadequate response or contraindication to BB/CCB

Longterm Rhythm Control

    • Consider rhythm in rate-controlled patients with

      • Symptoms or extreme impairment QOL

      • Recently diagnosed within 1 year

      • Multiple recurrences

      • Arrhythmia-induced cardiomyopathy.

      • However long-term oral antiarrhythmic therapy when AF becomes permanent

      • AVOID IF: advanced sinus or AV nodal disease unless PPM or ICD

    • Intermittent antiarrhythmic "pill in pocket” if 1-2 episodes / year

    • Normal Systolic Function

      • Dronedarone 400mg PO BID (avoid in permanent AF or CHF)

      • Flecainide (50-75mg daily, max 150mg) or Propafenone (150mg daily, max 300mg) used with BB (eg. Metoprolol 25mg) or ND-CCB

        • Time to convert 2-6h

        • Administer BB or ND-CCB ≥ 30mins before Class Ic antiarrhythmic (prevent risk of Atrial Flutter 1:1 AV conduction)

      • Sotalol (40mg BID, max 160mg)

      • Amiodarone

    • LV systolic dysfunction or CHF

      • Amiodarone:

        • Loading: 400 mg PO twice daily x 1 week then 400 mg daily x 2 weeks, or 400 mg daily x 1 month

        • Maintenance: 100-200mg daily

      • CAD:

        • Amiodarone, Dronedarone, Sotalol

    • Catheter Ablation

      • First line for symptomatic Atrial Flutter

      • Consider if symptomatic despite antiarrhythmics, if rhythm control strategy remains desired

    • Not an alternative to anticoagulation – still need anticoagulation after successful catheter ablation


    • CHADS65 (Congestive Heart Failure, Hypertension, Age 65, Diabetes, Stroke/Transient Ischemic Attack)

      • OAC alone if age >65, or stroke/TIA, or HTN or HF or Diabetes

      • ASA alone if CHADS65=0, and arterial vascular disease (coronary, aortic, peripheral) with none of above

    • DOAC preferred over warfarin in non-valvular AF (warfarin recommended in valvular AF, breastfeeding, liver failure, gastric bypass)

      • Careful in low eCrCl, measure CrCl regularly (6-12 months) and with acute illness

      • Apixaban 5mg PO BID (2.5mg PO BID if two of creat>133mcmol/L, age>80y, wt ≤60kg), avoid in CrCl<15)

      • Rivaroxaban 20mg PO daily (15mg PO daily in CrCl 30-49, avoid in CrCl<30)

      • Edoxaban 60mg PO daily (30mg PO daily in CrCl 30-49, weight ≤60kg, P-glycoprotein inhibitors)

        • Edoxaban 15mg PO daily can be considered in elderly patients when standard oral anticoagulants are considered inappropriate (eg. bleeding risk)

      • Dabigatran 150mg PO BID (110mg PO BID if age≥80y or >75y and high risk of bleed, avoid in CrCl<30)

      • Consider clopidogrel if NSTEACS/STEMI or recent elective PCI (indicated for 12 months)

      • Reversal of dabigatran with idarucizumab in emergency

    • Temporary interruption for procedures (restart 24h after procedure)

      • HASBLED for high risk of bleeding: Hypertension, Abnormal liver or kidney function, Stroke, Bleeding, Labile INRs, Elderly>65, Drugs (Alcohol/ASA/NSAID/plavix)

      • Low-risk procedures (eg. pacemaker, dental procedures, laparoscopic, gastroscopy/colonoscopy) do not need to have OAC interrupted

      • If STOPPING (calculator)

        • Aspirin or clopidogrel: 5-7 days (7-10 days for high risk of major bleeding)

        • Warfarin: 5 days (INR < 1.5 for a procedure with an intermediate risk, < 1.2 for a procedure with a higher risk of major bleeding)

        • DOAC: 3d

Last edited 2021-04-01

N. Nguyen, K. Chan