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Q wave Time frame for STEMI’s

by on February 10, 2011


A) Shows the normal QRS complex in a lead. 

B & C) Within hours of the clinical onset of an MI, there is ST segment elevation. At this stage no QRS or T wave changes have occurred. This indicates myocardial damage only, not definitive evidence of infarction.

D) Within days, the R wave voltage falls and abnormal Q waves appear. This is sufficient evidence of an infarction. In addition, T wave inversion will also have appeared but the ST segment elevation may be less obvious than before.

E) Within one or more weeks, the ST segment changes revert completely to normal. The R wave voltage remains low and the abnormal Q waves persist. Deep, symmetrical T wave inversion may develop at this stage.

F) Months after the MI, the T waves may gradually return to normal. The abnormal Q waves and reduced R wave voltage persist.

Occasionally, all evidence of infarction may be lost with the passing of time; this is due to shrinkage of scar tissue.

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