Pathologic Q Waves

A pathologic Q wave

Pathologic Q waves are a sign of previous 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.

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

Definition of a pathologic Q wave

Any Q wave in leads V1-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).

Notes

• Absence of pathologic Q waves does not exclude a myocardial infarction!
• Lead III often shows Q waves, which are not pathologic as long as Q waves are absent in leads II and aVF (the contiguous leads)

For those interested: the Minnesota Code Classification System for Electrocardiographic Findings contains a very extensive definition of pathologic Q waves.

Referenties

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1. Alpert pmid=10987628

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