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Atrial Fibrillation, Emergency Medicine

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Atrial Fibrillation, Emergency Medicine

Basics

Description

IV form for flecainide, propafenone, and sotalol not approved for use in US; must be infused slowly.

427.31 Atrial fibrillation

  • Dysrhythmia characterized by seemingly disorganized atrial depolarizations without effective atrial contraction
  • Caused by multiple re-entrant waveforms within the atria
  • Atrial rate ranges from 350-600 beats per minute (bpm).
  • Results in loss of organized atrial contractions and rapid ventricular rate:Decrease in cardiac outputProne to embolus formation
  • Most common clinical arrhythmia:Prevalence increasing with ageMen are at higher risk
  • Decrease in cardiac output
  • Prone to embolus formation
  • Prevalence increasing with age
  • Men are at higher risk

Etiology

  • Systemic disease:HTNHyperthyroidismChronic pulmonary diseaseInfectionPulmonary embolusHypoxiaDrugs (e.g., sympathomimetics)Acute alcohol ingestion (holiday heart syndrome)ObesityElectrolyte disturbanceThyroid disease
  • Underlying cardiac disease:CardiomyopathyCADValvular disease, especially mitralPericarditisSick sinus syndromeMyocardial contusionCHFCongenital heart disease
  • Idiopathic:Absence of any known etiologic factorNo clinical or echocardiographic evidence of heart disease
  • HTN
  • Hyperthyroidism
  • Chronic pulmonary disease
  • Infection
  • Pulmonary embolus
  • Hypoxia
  • Drugs (e.g., sympathomimetics)
  • Acute alcohol ingestion (holiday heart syndrome)
  • Obesity
  • Electrolyte disturbance
  • Thyroid disease
  • Cardiomyopathy
  • CAD
  • Valvular disease, especially mitral
  • Pericarditis
  • Sick sinus syndrome
  • Myocardial contusion
  • CHF
  • Congenital heart disease
  • Absence of any known etiologic factor
  • No clinical or echocardiographic evidence of heart disease

Diagnosis

Signs and Symptoms

  • Palpitations
  • Decreased cardiac output:WeaknessLight headednessSyncopeHypotensionAnginaPulmonary edemaAltered mental statusLower extremity edemaHepatojugular reflex
  • Embolus formation:Acute neurologic injuryMesenteric ischemia
  • Weakness
  • Light headedness
  • Syncope
  • Hypotension
  • Angina
  • Pulmonary edema
  • Altered mental status
  • Lower extremity edema
  • Hepatojugular reflex
  • Acute neurologic injury
  • Mesenteric ischemia
  • Onset of symptoms
  • Duration
  • Inciting factors
  • Prior episodes of fibrillation
  • Prior heart disease
  • Palpitations
  • Irregularly irregular pulse
  • Absence of A- waves in the jugular venous pulse
  • Pulse deficit with more rapid ventricular rates:The auscultated or palpated apical rate is faster than the rate palpated at the wrist
  • The auscultated or palpated apical rate is faster than the rate palpated at the wrist

Essential Workup

  • History and physical exam:Assess for instability and need for immediate cardioversionDuration of symptoms >48 hr or <48 hrEvidence of systemic disease or underlying cardiac disease
  • ECG: Signs of congestive heart failureAbsent P-waves replaced by fibrillatory (f) waves, 350-600 bpmF-waves vary in amplitude, morphology, and intervalsR-R intervals are irregularly irregularAbsence of an isoelectric baselineVentricular rate ranges from 80-150 bpm:If rate >200 associated with wide-irregular QRS, consider bypass tractSlower rate suggests abnormal AV node or presence of AV nodal blocking medicationUsually narrow QRS complexes unless:Functional aberrationPre-existing bundle branchPre-excitation with an accessory pathway
  • Assess for instability and need for immediate cardioversion
  • Duration of symptoms >48 hr or <48 hr
  • Evidence of systemic disease or underlying cardiac disease
  • Absent P-waves replaced by fibrillatory (f) waves, 350-600 bpm
  • F-waves vary in amplitude, morphology, and intervals
  • R-R intervals are irregularly irregular
  • Absence of an isoelectric baseline
  • Ventricular rate ranges from 80-150 bpm:If rate >200 associated with wide-irregular QRS, consider bypass tract
  • Slower rate suggests abnormal AV node or presence of AV nodal blocking medication
  • Usually narrow QRS complexes unless:Functional aberrationPre-existing bundle branchPre-excitation with an accessory pathway
  • If rate >200 associated with wide-irregular QRS, consider bypass tract
  • Functional aberration
  • Pre-existing bundle branch
  • Pre-excitation with an accessory pathway

Diagnosis Tests & Interpretation

  • CBC
  • Electrolytes
  • Cardiac enzymes-if ischemia is a concern
  • Thyroid function
  • Digoxin level-if patient is taking
  • Anticoagulation parameters
  • Urine drug screen
  • CXR
  • ECG

Differential Diagnosis

  • Atrial flutter with variable AV block
  • Multifocal atrial tachycardia
  • Sinus rhythm with frequent premature atrial contractions
  • Atrial tachycardia with variable AV block

Treatment

Pre-Hospital

  • IV access
  • Monitor
  • Oxygen
  • Cardioversion:In settings where patient is unstable
  • In settings where patient is unstable

Initial Stabilization/Therapy

  • IV
  • Oxygen
  • Monitor
  • Immediate synchronized electrical cardioversion starting at 200 J if the patient is unstable

Ed Treatment/Procedures

  • Hemodynamically unstable and life threatening:Myocardial infarction, pulmonary edema, heart failure that does not respond promptly to pharmacological measuresSynchronized electrical cardioversionBiphasic: Start at 100 J, higher success rateMonophasic: Start at 200 JSx duration <48 hr: Consider IV heparin bolus prior.Sx duration >48 hr: IV heparin, transesophageal echo to exclude atrial clot, cardioversion. Anticoagulate for 4 wk. Do not delay echo if life-threatening arrhythmia.Consider pretreatment with antiarrhythmic drugs and use anterior-posterior pad placement to increase likelihood of successChemical cardioversion:Choice of drug depends on history of CHF, high BP, LV hypertrophy, and CADMedications may be proarrhythmic and should be used with cautionAs with electrical cardioversion, appropriate anticoagulation will be necessary depending on the duration and presence/absence of clotIbutilideProcainamideFlecainidePropafenoneSotalol
  • Hemodynamically stable, mildly symptomatic:Treat underlying cause if 1 is identified.Identify if symptoms are <48 hr. If so consider synchronized cardioversion.>48 hr: Rhythm control does not offer mortality benefit over rate controlUse procainamide to treat stable patients with a suspected bypass tractRate control:Not necessary if rate <100 bpm or if rhythm spontaneously converts to sinusAV nodal blockers (calcium channel blockers, β-blockers, and digoxin) contraindicated if bypass tract suspected such as WPWCalcium channel blockers: Consider in patient with pulmonary disease. Use cautiously in patient with uncompensated CHF and 2nd- or 3rd-degree heart blockβ-blockers: Consider in patient with coronary artery disease (CAD). Use cautiously in patient with uncompensated CHF, 2nd- or 3rd-degree heart block, and pulmonary diseaseDigoxin: Consider in patient with pre-existing CHF.Amiodarone: Consider in refractory atrial fibrillationRhythm control and prophylaxis:Includes procainamide, sotalol, amiodarone, dofetilideAmiodarone: Only agent with strong data to support initiation for outpatient treatmentElective cardioversion:Oral anticoagulation with therapeutic levels for 3 wk prior to and 4 wk afterStable patients with atrial fibrillation and WPW can be treated with procainamide or ibutilide, although cardioversion may be preferred
  • Anticoagulation determined by CHADS2 scoring:1 point for each of the following:History of cardiac failureHistory of HTNAge ≥75 yrDiabetes2 points for a history of stroke or TIAScore of 0:81-325 mg/day of aspirinScore of 1:Either 81-325 mg/day of aspirin or adjusted-dose warfarin with a target INR of 2.5Score >1:Adjusted-dose warfarin with a target INR of 2.5 (range 2-3)Adjusted annual stroke rate increases from 1.9% for a CHADS2 score of 0 to 18.2% for a CHADS2 score of 6Aspirin:Patients with contraindications to anticoagulation and unreliable individualsPatients with low stroke risk
  • Myocardial infarction, pulmonary edema, heart failure that does not respond promptly to pharmacological measures
  • Synchronized electrical cardioversionBiphasic: Start at 100 J, higher success rateMonophasic: Start at 200 JSx duration <48 hr: Consider IV heparin bolus prior.Sx duration >48 hr: IV heparin, transesophageal echo to exclude atrial clot, cardioversion. Anticoagulate for 4 wk. Do not delay echo if life-threatening arrhythmia.Consider pretreatment with antiarrhythmic drugs and use anterior-posterior pad placement to increase likelihood of success
  • Chemical cardioversion:Choice of drug depends on history of CHF, high BP, LV hypertrophy, and CADMedications may be proarrhythmic and should be used with cautionAs with electrical cardioversion, appropriate anticoagulation will be necessary depending on the duration and presence/absence of clotIbutilideProcainamideFlecainidePropafenoneSotalol
  • Biphasic: Start at 100 J, higher success rate
  • Monophasic: Start at 200 J
  • Sx duration <48 hr: Consider IV heparin bolus prior.
  • Sx duration >48 hr: IV heparin, transesophageal echo to exclude atrial clot, cardioversion. Anticoagulate for 4 wk. Do not delay echo if life-threatening arrhythmia.
  • Consider pretreatment with antiarrhythmic drugs and use anterior-posterior pad placement to increase likelihood of success
  • Choice of drug depends on history of CHF, high BP, LV hypertrophy, and CAD
  • Medications may be proarrhythmic and should be used with caution
  • As with electrical cardioversion, appropriate anticoagulation will be necessary depending on the duration and presence/absence of clot
  • Ibutilide
  • Procainamide
  • Flecainide
  • Propafenone
  • Sotalol
  • Treat underlying cause if 1 is identified.
  • Identify if symptoms are <48 hr. If so consider synchronized cardioversion.
  • >48 hr: Rhythm control does not offer mortality benefit over rate control
  • Use procainamide to treat stable patients with a suspected bypass tract
  • Rate control:Not necessary if rate <100 bpm or if rhythm spontaneously converts to sinusAV nodal blockers (calcium channel blockers, β-blockers, and digoxin) contraindicated if bypass tract suspected such as WPWCalcium channel blockers: Consider in patient with pulmonary disease. Use cautiously in patient with uncompensated CHF and 2nd- or 3rd-degree heart blockβ-blockers: Consider in patient with coronary artery disease (CAD). Use cautiously in patient with uncompensated CHF, 2nd- or 3rd-degree heart block, and pulmonary diseaseDigoxin: Consider in patient with pre-existing CHF.Amiodarone: Consider in refractory atrial fibrillation
  • Rhythm control and prophylaxis:Includes procainamide, sotalol, amiodarone, dofetilideAmiodarone: Only agent with strong data to support initiation for outpatient treatment
  • Elective cardioversion:Oral anticoagulation with therapeutic levels for 3 wk prior to and 4 wk after
  • Stable patients with atrial fibrillation and WPW can be treated with procainamide or ibutilide, although cardioversion may be preferred
  • Not necessary if rate <100 bpm or if rhythm spontaneously converts to sinus
  • AV nodal blockers (calcium channel blockers, β-blockers, and digoxin) contraindicated if bypass tract suspected such as WPW
  • Calcium channel blockers: Consider in patient with pulmonary disease. Use cautiously in patient with uncompensated CHF and 2nd- or 3rd-degree heart block
  • β-blockers: Consider in patient with coronary artery disease (CAD). Use cautiously in patient with uncompensated CHF, 2nd- or 3rd-degree heart block, and pulmonary disease
  • Digoxin: Consider in patient with pre-existing CHF.
  • Amiodarone: Consider in refractory atrial fibrillation
  • Includes procainamide, sotalol, amiodarone, dofetilide
  • Amiodarone: Only agent with strong data to support initiation for outpatient treatment
  • Oral anticoagulation with therapeutic levels for 3 wk prior to and 4 wk after
  • 1 point for each of the following:History of cardiac failureHistory of HTNAge ≥75 yrDiabetes
  • 2 points for a history of stroke or TIA
  • Score of 0:81-325 mg/day of aspirin
  • Score of 1:Either 81-325 mg/day of aspirin or adjusted-dose warfarin with a target INR of 2.5
  • Score >1:Adjusted-dose warfarin with a target INR of 2.5 (range 2-3)
  • Adjusted annual stroke rate increases from 1.9% for a CHADS2 score of 0 to 18.2% for a CHADS2 score of 6
  • Aspirin:Patients with contraindications to anticoagulation and unreliable individualsPatients with low stroke risk
  • History of cardiac failure
  • History of HTN
  • Age ≥75 yr
  • Diabetes
  • 81-325 mg/day of aspirin
  • Either 81-325 mg/day of aspirin or adjusted-dose warfarin with a target INR of 2.5
  • Adjusted-dose warfarin with a target INR of 2.5 (range 2-3)
  • Patients with contraindications to anticoagulation and unreliable individuals
  • Patients with low stroke risk

Medication

  • Metoprolol:5-10 mg slow IV push at 5 min intervals to total of 15 mg25 mg-100 mg oral BID
  • Diltiazem:0.25 mg/kg IV over 2 min; if unsuccessful, repeat in 15 min as 0.35 mg/kg IV over 2 min; maintenance infusion of 5 mg/h usually started to maintain rate control.120-300 mg oral daily
  • Digoxin:0.5 mg IV initially, then 0.25 mg IV q4h until desired effect
  • Esmolol:0.5 mg/kg over 1 min; maintenance infusion at 0.05 mg/kg/min over 4 min
  • Propranolol:0.1 mg/kg IV divided into equal doses at 2-3 min intervals
  • Verapamil:2.5-5 mg IV bolus over 2 min; may repeat with 5-10 mg q15-30min to max. of 20 mg120-300 mg PO daily
  • Amiodarone:5-7 mg/kg over 30-60 min, then 1.2-1.8 g/d continuous infusion or in divided PO doses until 10 g total600-800 mg/d divided dose until 10 g total, then 200-400 mg/d maintenance
  • Procainamide: 15-18 mg/kg loading dose administered as a slow infusion over 30 min. Max.: 1 g. Then 2-6 mg/min infusion.
  • Quinidine gluconate: 324-648 mg PO q8-12h: (extended release tabs)
  • Ibutilide: 1 mg IV for patients >60 kg; 0.01 mg/kg IV for patients <60 kg infused over 10 min; can be repeated once if sinus rhythm not restored within 10 min. Requires normal QTc, no history of torsades, no hypokalemia. Patients must be monitored for 4 h for QT prolongation, Torsades de Pointes, and ventricular tachycardia.
  • Flecainide: 2 mg/kg IV at 10 mg/min PO. Do not give in patients with structural heart disease.
  • Propafenone: 1-2 mg/kg IV at 10 mg/min
  • Sotalol: 75 mg infused IV over 5 h BID if CrCl >60 mL/min. Give QD if CrCl 40-60 mL/min
  • Heparin: Load 80 U/kg IV; infusion at 18 U/kg/h. Dosage adjustment required in obese patients
  • Low-molecular-weight heparin: 1 mg/kg SQ BID
  • Warfarin sodium: 2.5-5 mg/d PO, dosage adjustments based on INR
  • Aspirin: 50-325 mg/d
  • 5-10 mg slow IV push at 5 min intervals to total of 15 mg
  • 25 mg-100 mg oral BID
  • 0.25 mg/kg IV over 2 min; if unsuccessful, repeat in 15 min as 0.35 mg/kg IV over 2 min; maintenance infusion of 5 mg/h usually started to maintain rate control.
  • 120-300 mg oral daily
  • 0.5 mg IV initially, then 0.25 mg IV q4h until desired effect
  • 0.5 mg/kg over 1 min; maintenance infusion at 0.05 mg/kg/min over 4 min
  • 0.1 mg/kg IV divided into equal doses at 2-3 min intervals
  • 2.5-5 mg IV bolus over 2 min; may repeat with 5-10 mg q15-30min to max. of 20 mg
  • 120-300 mg PO daily
  • 5-7 mg/kg over 30-60 min, then 1.2-1.8 g/d continuous infusion or in divided PO doses until 10 g total
  • 600-800 mg/d divided dose until 10 g total, then 200-400 mg/d maintenance

Follow-Up

Disposition

  • Unstable AF:Inability to control rate
  • High risk for stroke:Prior cardiovascular accidentCHF
  • Associated medical problems contributing to the AF that require inpatient management
  • Inability to control rate
  • Prior cardiovascular accident
  • CHF
  • Conversion to sinus rhythm if symptoms <48 hr
  • Chronic AF with appropriate ventricular rate control and anticoagulation
  • New-onset AF with rate control and anticoagulation
  • Cardiology or an electrophysiologist
  • Evaluation for outpatient cardioversion

Follow-Up Recommendations

  • INR check if placed on warfarin
  • The patient should return to the ED if feeling faint, dizzy, numbness or weakness of the face or limbs, or trouble seeing or speaking

Pearls and Pitfalls

  • If hemodynamically unstable and life threatening, synchronized cardioversion is warranted
  • Rate or rhythm control is an individualized option for stable atrial fibrillation using β-blockers, calcium channel blockers, or antiarrhythmics
  • Do not mistake F-waves or U-waves as P-waves. Can misdiagnose AF as a sinus rhythm.
  • Do not use channel blockers, β-blockers, or digoxin in AF with a wide complex AF in a patient with an underlying bypass tract

Additional Reading

  • Chinitz JS, Halperin JL, Reddy VY, et al. Rate or rhythm control for atrial fibrillation: Update and controversies. Am J Med. 2012;125(11):1049-1056.
  • Crandall MA, Bradley DJ, Packer DL, et al. Contemporary management of atrial fibrillation: Update on anticoagulation and invasive management strategies. Mayo Clin Proc. 2009;84:643-662.
  • Fuster V, Ryden LE, Asinger RW, et al. ACC/AHA/ESC Guidelines for the Management of Patients with Atrial Fibrillation: Executive Summary a Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology. Circulation. 2006;148(4):e149-e246.
  • Khoo CW, Lip GY. Acute management of atrial fibrillation. Chest. 2009;135(3):849-859.
  • Stiell IG, Clement CM, Perry JJ, et al. Association of the Ottawa aggressive protocol with rapid discharge of emergency department patients with recent-onset atrial fibrillation or flutter. CJEM. 2010;12(3):181-191.
  • Wann LS, Curtis AB, January CT, et al. 2011 ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (updating the 2006 guideline): A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2011;57(2):223-242.

Codes

ICD9

ICD10

  • I48.0 Paroxysmal atrial fibrillation
  • I48.1 Persistent atrial fibrillation
  • I48.91 Unspecified atrial fibrillation
  • I48.2 Chronic atrial fibrillation

SNOMED

  • 49436004 Atrial fibrillation (disorder)
  • 282825002 Paroxysmal atrial fibrillation (disorder)
  • 440059007 persistent atrial fibrillation (disorder)
  • 426749004 Chronic atrial fibrillation (disorder)