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Pathologic Q waves are a sign of '''previous [[Myocardial Infarction|myocardial infarction]]'''. The are the result of absence of electrical activity. A myocardial infarction can be thought of as an elecrical 'hole' as scar tissue is electrically dead and therefore results in pathologic Q waves. Pathologic Q waves are not an early sign of myocardial infarction, but '''generally take several hours to days to develop'''. Once pathologic Q waves have developed they rarely go away. However, if the myocardial infarction is reperfused early (e.g. as a result of percutaneous coronary intervention) stunned myocardial tissue can recover and pathologic Q waves disappear. In all other situations they '''usually persist indefinitely'''.
Pathologic Q waves are a sign of '''previous [[Myocardial Infarction|myocardial infarction]]'''. The are the result of absence of electrical activity. A myocardial infarction can be thought of as an elecrical 'hole' as scar tissue is electrically dead and therefore results in pathologic Q waves. Pathologic Q waves are not an early sign of myocardial infarction, but '''generally take several hours to days to develop'''. Once pathologic Q waves have developed they rarely go away. However, if the myocardial infarction is reperfused early (e.g. as a result of percutaneous coronary intervention) stunned myocardial tissue can recover and pathologic Q waves disappear. In all other situations they '''usually persist indefinitely'''.


The precise criteria for pathologic Q waves have been debated. Here we present the latest definition as accepted by the ESC and ACC.<cite>Alpert</cite>
The precise criteria for pathologic Q waves have been debated. Here we present the latest definition as accepted by the ESC and ACC.<cite>Thygesen</cite>


;Definition of a pathologic Q wave
;Definition of a pathologic Q wave
*Any Q wave in leads V1-V3
:Any Q-wave in leads V2–V3 >= 0.02 s or QS complex in leads V2 and V3
*Q wave > or = to 30ms (0.03s) in leads I, II, aVL, aVF, V4, V4, or V6 (the Q wave changes must be present in any two contiguous lead, and be > or = 1mm in depth).
:Q-wave >= 0.03 s and > 0.1 mV deep or QS complex in leads I, II, aVL, aVF, or
V4–V6 in any two leads of a contiguous lead grouping (I, aVL,V6; V4–V6; II, III,
and aVF)*
:R-wave >= 0.04 s in V1–V2 and R/S > 1 with a concordant positive T-wave in the
absence of a conduction defect


'''Notes'''
'''Notes'''
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<biblio>
<biblio>
#Alpert pmid=10987628
#Alpert pmid=10987628
#Thygesen pmid=17951284
</biblio>
</biblio>
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