II. Diagnostics: Electrocardiogram

  1. No history of AV nodal blocking drugs
  2. No discrete atrial activity
    1. Discrete P Waves absent
    2. Atrial Fibrillation waves (F Waves) seen
      1. Rapid oscillations or fibrillatory waves
      2. Small irregular waves at rate of 150-300 bpm
      3. Difficult to detect at high atrial rates (fine)
  3. Ventricular response
    1. Rapid rate up to 160-200 bpm
    2. Irregularly irregular rhythm
    3. Inconsistent R-R interval
  4. Variants
    1. Irregular Wide Complex Tachycardia
      1. Suggests Atrial Fibrillation with aberrant conduction (Ashman Phenomenon)
    2. Heart Rate faster than 200/min
      1. Accessory pathway (e.g. Atrial Fibrillation with Wolff-Parkinson-White or WPW)

III. Differential Diagnosis: Atrial Fibrillation Causes

  1. Acute coronary ischemia
    1. Left QRS Axis
    2. Left P Wave Axis
  2. Acute Pulmonary Disease
    1. Right QRS Axis
    2. Right P Wave Axis
  3. Mitral Stenosis
    1. Right QRS Axis
    2. Left P Wave Axis
  4. Lone Atrial Fibrillation
    1. Normal or Left QRS Axis
    2. Normal or Left P Wave Axis
  5. Thyrotoxicosis
    1. Normal QRS Axis
    2. Normal P Wave Axis
  6. Holiday Heart
    1. Normal QRS Axis
    2. Normal P Wave Axis
  7. Atrial Flutter
    1. Prominent saw tooth waves
    2. Atrial rate slower than Atrial Fibrillation

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