Pathological Q-wave (QW) in the electrocardiogram (ECG) before primary percutaneous coronary intervention (primary PCI) is a strong prognostic marker in patients with ST-segment elevationÂ myocardial infarctionÂ (STEMI). However, current binary QW criteria are either not clinically applicable or have a lack of diagnostic performance. Accordingly, we evaluated the association between duration, depth and area of QW and markers of the effect of reperfusion (reperfusion success).
A total of 516 patients with their first STEMI had obtained an ECG before primary PCI and an acute cardiac magnetic resonance imaging (CMR) at day 1 (interquartile range [IQR], 1-1) and at follow-up at day 92 (IQR, 89-96). The largest measurable QW in ECG was used for analysis of duration, depth and area of QW (QW morphology). The QW morphology was evaluated as a continuous variable in linear regression models and as a variable divided in four equally large groups.
The QW morphology as four equally large groups was significantly associated with all CMR endpoints (pÂ â‰¤Â 0.001) and showed a linear relationship (pÂ â‰¤Â 0.001) with final infarct size (for QW duration, Î˛Â =Â 0.47; QW depth, Î˛Â =Â 0.41 and QW area, Î˛Â =Â 0.39), final infarct transmurality (for QW duration, Î˛Â =Â 0.36; QW depth, Î˛Â =Â 0.26 and QW area, Î˛Â =Â 0.23) and finalÂ myocardialÂ salvage index (for QW duration, Î˛Â =Â -0.34; QW depth, Î˛Â =Â -0.26 and QW area, Î˛Â =Â -0.24).
Although modest, the QW morphology in STEMI patients showed significant linear association with markers of reperfusion success. Hence, it is suggested that the term pathological is not used as a dichotomous parameter in patients with STEMI but rather evaluated on the basis of extent.