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)
  • Decrease in cardiac output with 3-fold risk of heart failure
  • Prone to embolus formation with 5-fold risk of stroke
  • Most common clinical arrhythmia:
    • Prevalence increasing with age


  • Systemic 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
  • Underlying cardiac disease:
    • Cardiomyopathy
    • CAD
    • Valvular disease, especially mitral
    • Pericarditis
    • Sick sinus syndrome
    • Myocardial contusion
    • CHF
    • Congenital heart disease
  • Idiopathic:
    • Absence of any known etiologic factor
    • No clinical or echocardiographic evidence of heart disease

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