A case series of OMI: time for revisiting STEMI/NSTEMI ECG criteria

Abstract

Background: The current STEMI criteria fail to detect roughly one-third of occlusive MI (OMI). STEMI criteria demonstrated only a sensitivity of around 21% for OMI. Compared to STEMI, patients with NSTEMI-OMI have higher short-term and long-term all-cause mortality and longer reperfusion delays. This case series presents three NSTEMI patients with OMI and a delayed reperfusion strategy.

Case presentation: We present three cases of patients initially diagnosed with NSTEMI who were later found to have occlusive myocardial infarction (OMI) based on angiographic findings, all of whom underwent delayed reperfusion strategies. The first two cases shared similar clinical profiles, presenting with typical infarct angina, elevated cardiac enzymes, and regional wall motion abnormalities on echocardiography. Their electrocardiograms showed bifascicular blocks, right bundle branch block (RBBB) with left posterior fascicular block (LPFB) in the first case, and RBBB with left anterior fascicular block (LAFB) in the second. Both were classified as high-risk NSTEMI and scheduled for an early invasive approach. Angiography revealed total occlusions in the OM1 and left main arteries, respectively. In the third case, the patient presented with new-onset angina and elevated cardiac biomarkers, but without ECG features fulfilling STEMI or high-risk OMI criteria. However, due to persistent chest pain despite initial treatment in the emergency department, an immediate invasive strategy was pursued. Coronary angiography revealed a total occlusion in the proximal left anterior descending (LAD) artery.

Conclusions: These three cases underscore the diagnostic challenge of identifying occlusive myocardial infarction (OMI) in patients presenting with acute coronary syndrome (ACS) when relying exclusively on traditional STEMI criteria. They emphasize the need to recognize alternative ECG markers indicative of acute coronary occlusion, as failure to do so may result in delayed reperfusion and subsequently worse clinical outcomes compared to patients who receive timely intervention based on prompt STEMI recognition.

Keywords: Delayed reperfusion; OMI/NOMI; STEMI/NSTEMI.

Fig. 1

ECG (4 h onset) demonstrated sinus rhythm with right bundle branch block with ST depression in V2–V3 and left posterior fascicular block

Fig. 2

Early PCI procedure. a A diagnostic angiography revealed diffuse stenosis 70–80% at proximal LAD, diffuse stenosis 80–90% at proximal LCx, and total occlusion at proximal OM1 with TIMI Flow 0 (red arrow). b Right coronary artery (RCA) was dominant with discrete stenosis of 30–40% at osteal. c Successful PCI with implantation of 2.25 × 22 mm coronary stent at proximal OM1 with TIMI Flow 3

Fig. 3

ECG (24 h onset) demonstrated sinus tachycardia with right bundle branch block and left anterior fascicular block

Fig. 4

Early PCI procedure. a A diagnostic angiography revealed total occlusion at the proximal left main with TIMI flow 0 (red arrow). b RCA was dominant with subtotal occlusion at distal PL. c A successful PCI with POBA and thrombectomy was performed, and the result was TIMI Flow 3, residual stenosis, and thrombus

Fig. 5

ECG a (5 h onset) sinus rhythm, 69 bpm, Normo axis, P wave normal, PR interval of 160, QRS duration of 80 ms, Q wave (-), ST depression in V3–V6, subtle ST elevation in V1–V2, and prominent T wave in V2–V3. b A serial ECG (6 h onset) examination revealed normalization of ST depression in V3–V6 with a prominent T wave in V2–V3

Fig. 6

Immediate invasive strategy procedure. a A diagnostic angiography revealed total occlusion at the proximal LAD with TIMI flow 0 (red arrow). b RCA was dominant, with diffuse stenosis at 70% in the mid. c Successful PCI with implantation of 3.5 × 38 mm coronary stent and 2.5 × 32 mm coronary stent was performed with the result TIMI flow 3