Electrocardiographic criteria for anterior STEMI - Does the cut-off point affect treatment delay?

Diagnostic criteria for anterior STEMI differ between the European Society of Cardiology (ESC) and the European Resuscitation Council (ERC). A greater degree of ST-segment elevation is required to meet ERC criteria compared to ESC criteria. This may potentially lead to discrepancies in management between emergency teams and cardiologists, subsequent delay in reperfusion therapy and worse prognosis.

We performed an observational study in patients with anterior STEMI routinely treated with primary PCI and assessed whether differing electrocardiographic diagnostic criteria could impact treatment and short-term prognosis. All patients in the study had anterior STEMI confirmed by electrocardiographic ESC criteria and subsequent coronary angiography. Patients were divided into two groups. Those who did not meet ERC criteria in the index ECG were assigned to the "non-ERC" group and were compared with those who met them - the "ERC" group.

Out of 60 patients with anterior STEMI based on ESC criteria (mean age 66.9 ± 13.6 years, 70% males), 26 patients (44%) did not meet ERC criteria ("non-ERC" group) for STEMI. There were no significant differences in age, gender distribution or clinical characteristics between "ERC" and "non-ERC" patients. Total-Ischemic-Time, Patient-Delay, and System-Delay times were significantly longer in "non-ERC" group (433.1 ± 389.9 min vs. 264.2 ± 229.6 min, p = 0.03; 290.8 ± 337.6 min vs. 129.5 ± 144.9 min; p < 0.05 and 158.8 ± 158 vs 134.6 ± 191 min, p < 0.02 respectively). There were no differences in In-Hospital-Delay, procedure duration, and success rate of PCI. Proximal LAD occlusion (64.7%) and TIMI = 0 flow (73.5%) tended to be more frequently observed in "ERC" than in the "non-ERC" group (53.8% and 65.4%, respectively). Hospitalization time and LVEF (44.4 ± 8.7 vs 42.8 ± 9.5%, p = 0.53) were similar between groups.

Differences in electrocardiographic criteria for anterior STEMI leave a significant proportion of patients undiagnosed. Patients with STEMI who failed to meet less strict ERC criteria had more distal LAD disease with better TIMI flow but received reperfusion therapy later. Thus, character of the disease may compensate for treatment delay but this needs to be further evaluated. Finally, lowering the cut-off point with stricter criteria compromises specificity and is expected to increase the false positive rate, however there were no false positives in this study as all patients were angiographically confirmed to have acute coronary obstruction.