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Pathologic Q waves
From WikEM
(Redirected from Q Waves)
Evaluation
- Significant if >1 box wide or if is 1/3 of entire QRS amplitude
- Early Repolarization:
- ST Elevation most prominent in lat precord leads (V4-6) but no reciprocal changs
- T waves usually broad, tall (>5mm) & upright
- Limb leads may also have ST elevation, rarely >2 mm
Details
- Q waves do not always indicate infarction
- Must distinguish normal septal q waves from pathologic Q waves:
- Normal septal q wave: <0.04s, low amplitude
- Abnormal septal q wave: >0.04s in I OR in II, III, AND aVF OR V3, V4, V5, AND V6
- Q-wave equivalents in the precordial leads:
- R-wave diminution or poor R-wave progression
- Reverse R-wave progression (R waves increase then decrease in amplitude)
- Must distinguish from lead misplacement
- Tall R waves in V1, V2 (representing "Q waves" from posterior infarction)
Differential Diagnosis
Q Wave (Pathologic)
- Pathologic Q waves (Ischemic)
- LBBB
- LVH
- Chronic lung disease
- Hypertrophic cardiomyopathy
- Dilated cardiomyopathy
