II. Epidemiology

  1. Limited diagnostic value in Pulmonary Embolism
  2. EKG Changes have low sensitivity and low Specificity for Pulmonary Embolism
    1. However, in combination, may add to likelihood of Pulmonary Embolism
    2. Normal EKG does not exclude Pulmonary Embolism

III. Findings: General

  1. See Right Ventricular Strain EKG Pattern
  2. Electrocardiogram shows nonspecific changes in 80% of cases
  3. 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
  4. Findings with increased probablity of Pulmonary Embolism (especially moderate to severe PE)
    1. T Wave Inversion especially in anteroseptal (v1-v4) and possibly inferior (II, III, aVF) leads
  5. 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)
    6. ST Segment Elevation in aVR
      1. Also seen in Proximal LAD Occlusion
    7. P Pulmonale
      1. Suggests right atrial enlargement
      2. Peaked P Waves in the inferior leads >2.5 mm and taller in I than III

IV. Findings: Daniel EKG Criteria for Massive PE

  1. Criteria (21 points possible)
    1. Score 2: Sinus Tachycardia
    2. Score 2: Incomplete Right Bundle Branch Block
    3. Socre 3: Complete Right Bundle Branch Block
    4. Score 3-12: T-wave inversion in leads V1 through V4 (score 3 points for each lead with T inversion)
    5. Score 1: Q Wave in lead III
    6. Score 1: Inverted T Wave in lead III
    7. Score 2: Right heart strain pattern of S1 Q3 T3 (as described above)
  2. Interpretation
    1. Score >5 is consistent with Pulmonary Embolism
    2. Score >10 is consistent with severe or massive Pulmonary Embolism
  3. References
    1. Daniel (2001) Chest 120(2):474-81 +PMID:11502646

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