I. Epidemiology

  1. Limited diagnostic value in Pulmonary Embolism
  2. Changes have low sensitivity and low Specificity

II. Findings

  1. Electrocardiogram shows nonspecific changes in 80% of cases
  2. Classic Findings (Right heart strain): S1 Q3 T3 (seen in under 20% of cases)
    1. S Wave in Lead I
    2. Q Wave in Lead III
    3. T Wave Inversion in Lead III
  3. Findings with increased probablity of Pulmonary Embolism (especially moderate to severe PE)
    1. T Wave inversion especially in anteroseptal (v2-v3) and inferior (II, III, aVF) leads
  4. Common Findings
    1. Sinus Tachycardia
    2. Dysrhythmias
    3. Right sided strain pattern
      1. New Right Bundle Branch Block
      2. Right Axis Deviation
    4. Findings that mimic Myocardial Infarction
      1. ST segment changes
      2. T Wave changes
    5. Atrial Fibrillation (new onset)

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