Q waves: do they indicate full thickness infarcts?

Abstract

The link between pathological Q waves and myocardial necrosis was first observed at autopsy in the early 20th century, an observation that has continued to influence ECG interpretation to the present day. As students we are taught that pathological Q waves on an electrocardiogram (ECG) represent permanent, full thickness myocardial necrosis thus implying that the damage is done and subsequent treatment futile: but could advancing technology challenge this widely held perception? With the development of cardiac magnetic resonance imaging (CMRI) and positron emission tomography (PET) the question regarding the significance of Q waves has been asked at a new level.

The purpose of this article is to compare theory, pathological observations, CMRI/PET studies and to discuss how myocardial stunning and hibernation are influencing our perception of the Q wave. There are many factors that can influence QRS manifestation which may or may not exhibit Q waves that are permanent or transient, sinister or benign and by oversimplifying the significance of these Q waves many patients could be denied life changing treatment.