Pathological Q Waves
April 24th, 2019
Overview
While T wave and ST changes revert post myocardial infarction, Q waves are permanent and thus their presence may indicate previous infarction.
Look For
A negative deflection that is either broad or deep:- Broad: >40ms (1mm) in duration
- Deep: >0.2mV (2mm) or >1/3 of R wave size
Non-pathological Q waves may occur in I, III, aVL, V5 and V5.
Causes of Pathological Q Waves
- Myocardial infarction
- Hypertrophic cardiomyopathy (inferior / anterior leads)
- Dilated cardiomyopathy (leads V1 to V4)
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