II. Interpretation

  1. Significant Q Waves (in at least 2 contiguous leads)
    1. One box (0.04 sec) wide or more AND
    2. One third height of R Wave (Unless isolated in Lead III)

III. Causes: Q-Wave MI

  1. See Electrocardiogram in Myocardial Infarction
  2. Q Waves in Leads I and aVL
    1. Lateral Myocardial Infarction
  3. Q Waves in Leads II, III and avF
    1. Inferior Myocardial Infarction
  4. Q Waves in Leads V1-V3
    1. Anterior-Septal Myocardial Infarction
  5. Q Waves in Leads V2-4
    1. Anterior Myocardial Infarction
  6. Q Waves in Leads V4-6
    1. Anterior-Lateral Myocardial Infarction

IV. Causes: Non-Infarction Causes

  1. Hypertrophic Cardiomyopathy
    1. Dagger-like (sharp, narrow <0.04 sec) prominent Q Waves in lateral leads (I, aVL, V4-6)
  2. Pulmonary Embolism
    1. Q Waves in Lead III and possibly avF with right sided strain
  3. Left Ventricular Hypertrophy
  4. Right Ventricular Hypertrophy
  5. Left Bundle Branch Block
  6. Left Anterior Fascicular Block
  7. Chronic Lung Disease
  8. Cardiomyopathy (e.g. infiltrative Cardiomyopathy, Myocarditis)
  9. Congenital disorder (e.g. corrected Great Vessel Transposition, Muscular Dystrophy)
  10. Myocardial Contusion
  11. Hyperkalemia

V. References

  1. O'Keefe (2010) ECG Criteria Book, Jones and Bartlett, p. 43-44

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