Atrial fibrillation (main): Difference between revisions
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==Background==
==Background==
Causes:
*Causes:
#Cardiac (atrial enlargement)
**Cardiac (atrial enlargement)
##HTN, CAD, valvular disease, cardiomyopathy, ACS
***Hypertension
#Noncardiac (increased automaticity)
***Ischemic heart disease
##Hyperthyroidism, PE, hypoxic pulmonary conditions, ethanol ("holiday heart"), drugs (cocaine, TCA)  
***Rheumatic heart disease
##Need to treat underlying cause
**Noncardiac (increased automaticity)
***Thyrotoxicosis
***Chronic lung disease
***Pericarditis
***Ethanol ("holiday heart")
***PE
***Drugs (cocaine, TCA)  


==Diagnosis==
==Clinical Features==
Presentation
#Asymptomatic - 44%
#Asymptomatic - 44%
#Palpitations - 32%
#Palpitations - 32%
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#Also can present with decompensated heart failure, acute pulmonary edema  
#Also can present with decompensated heart failure, acute pulmonary edema  


History
==Diagnosis==
*History of afib?
*3 patterns on ECG:
**If yes, on medication?
**If no, was the onset recgonized?
*<48hrs duration?
 
Physical Exam
*Evidence of hemodynamic instability, CHF?
 
 
'''ECG (3 types)'''
#Typical
#Typical
##Irregularly, irregular R waves
##Irregularly, irregular R waves
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==Treatment==
==Treatment==
See [[Atrial Fibrillation (RVR)]]  
*Rate control
 
**See: [[Atrial Fibrillation (RVR)]]  
For Acute (<48hrs) debate regarding rhythm vs. rate control
*Anti-thrombotic therapy
 
**Chronic and paroxysmal a fib are associated with thrombus formation
For Chronic = rate control
 
===Anti-thrombotic therapy===
Chronic and paroxysmal a fib are associated with thrombus formation


'''CHADS2 Score'''
'''CHADS2 Score'''
#Chf (1pt)
#CHF (1pt)
#HTN (1pt)
#HTN (1pt)
#Age>75 (1pt)
#Age>75 (1pt)
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#Stroke/TIA (2pts)
#Stroke/TIA (2pts)


Score 0 - consider no treatment or ASA
*Score 0: consider no treatment or ASA
 
*Score 1: consider warfarin or ASA
Score 1 - consider coumadin or ASAn
*Score 2-6: consider warfarin (INR goal = 2-3)
 
*All patients with valvular disease should be on anticoagulation  
Score 2-6 - consider coumadin (INR goal = 2-3)
 
All patients with valvular disease should be on anticoagulation  
 
===Cardioversion===
*If unstable OR low risk for clot (risk still about 1%)
**Low Risk = <48 hrs symptoms, new dx, no hx similar episodes, no cause found by history, no LV dysfunction, no mitral valve dz, no prior thromboembolic event
 
====Chemical Cardioversion====
#Ibutilide (Class III)
##1 mg over 10 min in pts >60 kg (or 0.01 mg/kg)
##can repeat dose once if not sinus within 10 min of infusion
##Avoid in hypoK, hypoMg, prolonged QT, torsades
##Efficacy superior at 90 min to IV procainamide /sotalol
##(monitor for few hours for polymorph VT (8% incidence), then d/c home with PO beta/Ca blockers)
 
Other Options:
#Procainamide up to 1 gm IV (100 mg Q5 min) @ <20 mg/min
##Prefered by some authors
#Amiodarone 0.75 mg/kg IV over 15 min.  1200 mg in 24h
#Flecainide 300mg po
 
If does not quickly to chemical cardioversion, proceed to electrical


==Disposition==
==Disposition==
#New-Onset Afib (<48hrs)
*Consider discharge for paroxysmal A-fib successfully treated if none of the following:
##In the absence of angina, ECG evidence of MI, or recent infarction, no need to admit to r/o MI!
**Hemodynamic instability
##If stable, no history of heart disease, no other indication for admission then most patients can be directly d/c'd from the ED after successful pharmacologic or electrical cardioversion
**Myocardial ischemia
##Outpatient TTE, cardiology follow-up
**CHF exacerbation
 
**Symptomatic recurrence in the ED
===Indications for hospitalization===
#Hemodynamic instability
#Myocardial ischemia
#CHF exacerbation 2/2 a-fib
#Symptomatic recurrence in the ED


==Complications==
==Complications==
#Hemodynamic compromise
#Hemodynamic compromise
##Lowers CO by 20-30%
##A-fib lowers CO by 20-30%
##Impaired coronary blood flow  
##Impaired coronary blood flow  
#Arrhythmogenesis
#Arrhythmogenesis

Revision as of 05:23, 26 March 2012

Background

  • Causes:
    • Cardiac (atrial enlargement)
      • Hypertension
      • Ischemic heart disease
      • Rheumatic heart disease
    • Noncardiac (increased automaticity)
      • Thyrotoxicosis
      • Chronic lung disease
      • Pericarditis
      • Ethanol ("holiday heart")
      • PE
      • Drugs (cocaine, TCA)

Clinical Features

  1. Asymptomatic - 44%
  2. Palpitations - 32%
  3. Dyspnea - 10%
  4. Stroke - 2%
  5. Also can present with decompensated heart failure, acute pulmonary edema

Diagnosis

  • 3 patterns on ECG:
  1. Typical
    1. Irregularly, irregular R waves
    2. QRS rate 140-160/min
  2. Large fibrillatory waves
    1. May look like flutter waves
      1. Unlike a-flutter, the fibrillatory waves are irregular
  3. Slow, regular A-fib
    1. Due to complete AV block with escape rhythm
  • Ischemic changes?
  • Rate > 250? (think preexcitation)

Work-Up

  1. ECG
  2. Digoxin level (if appropriate)
  3. Chem-10
  4. TSH

Treatment

  • Rate control
  • Anti-thrombotic therapy
    • Chronic and paroxysmal a fib are associated with thrombus formation

CHADS2 Score

  1. CHF (1pt)
  2. HTN (1pt)
  3. Age>75 (1pt)
  4. DM (1pt)
  5. Stroke/TIA (2pts)
  • Score 0: consider no treatment or ASA
  • Score 1: consider warfarin or ASA
  • Score 2-6: consider warfarin (INR goal = 2-3)
  • All patients with valvular disease should be on anticoagulation

Disposition

  • Consider discharge for paroxysmal A-fib successfully treated if none of the following:
    • Hemodynamic instability
    • Myocardial ischemia
    • CHF exacerbation
    • Symptomatic recurrence in the ED

Complications

  1. Hemodynamic compromise
    1. A-fib lowers CO by 20-30%
    2. Impaired coronary blood flow
  2. Arrhythmogenesis
  3. Arterial thromboembolism

See Also

Source

  • UpToDate
  • Annals of EM; Jan 2011. 57(1)
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