Preprocedural Q-wave depth does not predict mortality after primary coronary intervention for ST-elevation myocardial infarction

Background

Pathologic Q waves on the admission electrocardiogram (ECG) have historically been markers of myocardial necrosis and adverse outcomes after ST-elevation myocardial infarction (STEMI). Although quantitative markers such as Q-wave width may add prognostic value, they can be difficult to apply clinically. We hypothesised that maximal and average pre–percutaneous coronary intervention (PCI) Q-wave depth could predict short- and medium-term mortality.

Methods

We performed a retrospective cohort study of consecutive STEMI patients undergoing primary PCI (N = 625). Pre-PCI ECGs were analysed using European Society of Cardiology/American Heart Association definitions to identify pathologic Q waves. Maximal and average Q-wave depth (mm) and infarct territory were recorded. Posterior patterns, bundle branch block confounding interpretation, and Q waves outside the culprit territory were excluded. Outcomes were all-cause mortality at 3 and 12 months.

Results

Of the 625 patients studied, 203 with pathologic Q waves in the infarct territory had complete depth measurements for analysis. Twelve-month mortality was 7.4% (15 of 203). Neither maximal nor average Q-wave depth was associated with mortality at 3 or 12 months in any infarct territory. Pain-to-balloon time demonstrated a weak positive correlation with maximal (Spearman rho = 0.204, P = 0.004) and average (rho = 0.152, P = 0.033) Q-wave depth.

Conclusions

In this small, observational cohort of STEMI patients undergoing primary PCI, preprocedural Q-wave depth was not associated with all-cause mortality at 3 or 12 months. These findings do not support Q-wave depth as a standalone pre-PCI prognostic marker; larger studies and alternative ECG measures may be more informative. Q-wave depth was weakly associated with total ischemic time, warranting further evaluation in larger multicentre cohorts.