The Post-ROSC ECG: Morphological Spectrum of Non-ST-Elevation Occlusion and Prognostic Markers After Cardiac Arrest.

BACKGROUND: Occlusive myocardial infarction (OMI) frequently presents without ST-elevation (NST-OMI) after return of spontaneous circulation (ROSC), complicating triage decisions. Aim of this study was to (i) characterise the distribution of NST-OMI patterns post-ROSC and (ii) determine whether quantitative ECG features are associated with survival. METHODS: In this retrospective single-centre analysis, the first post-ROSC ECG of cardiac arrest survivors admitted to a tertiary ICU (2020-2025) was evaluated for STEMI and NST-OMI patterns and for quantitative intervals (PQ, PR, P-wave, QRS, QTc). Coronary angiography (CAG) served as the reference standard for OMI. RESULTS: Of 214 patients, 101 had CAG-confirmed OMI, wherein left-main equivalent and Smith-modified Sgarbossa criteria were the most prevalent NST-OMI patterns (each 8%), followed by Aslanger pattern (5%), lateral OMI, shark-fin sign and hyperacute t-wave (each 4%). NST-OMI patterns were more prevalent both overall (35% vs. 24%) and among CAG-confirmed OMI cases (48% vs. 44%) yet underwent CAG less frequently (78% vs. 98%; p=0.002), with the highest 30-day mortality among NST-OMI patients not undergoing CAG (75%; p=0.005). Regarding ECG features, non-survivors had longer PR-segment (74 vs. 57ms; p=0.008) and QRS-duration (130 vs. 108ms; p=0.003), and shorter P-wave duration (105 vs. 108ms; p=0.027). After multivariable adjustment, PR-segment prolongation was independently associated with reduced 30-day survival (aOR 0.977 [0.956-0.998]; p=0.032). CONCLUSIONS: On the first post-ROSC ECG, angiographically confirmed occlusion concentrated around a small number of NST-OMI morphologies - findings of crucial importance for identification and appropriate management. PR-segment prolongation predicted reduced 30-day survival - indicating prognostic information beyond ischaemia detection.