Degree of ST-segment elevation in patients with STEMI reflects the acute ischemic burden and the salvage potential

Abstract

BackgroundST-segment elevation myocardial infarction (STEMI) is clinically diagnosed by significant ST-segment elevation (STE) in the electrocardiogram (ECG). The importance of the sum of significant ST-segment elevation (∑STE) before primary percutaneous coronary intervention (PPCI) – considered an indicator of the degree of ischemia - is sparse. We evaluated the association of ∑STE before PPCI with respect to area at risk, infarct size and myocardial salvage. MethodsA total of 503 patients with STEMI and available cardiac magnetic resonance (CMR) were included. CMR was performed at day 1 (interquartile range [IQR], 1–1) and at follow-up at day 92 (IQR, 88–96). The ECG before PPCI with the most prominent STE was used for analysis. Results∑STE divided into quartiles were progressive linearly associated with area at risk (p < 0.001), final infarct size (p < 0.001) and extent of microvascular obstruction (p < 0.001) and inverse linearly associated with final myocardial salvage (p < 0.001). Similar results were found for linear regression analyses. However, ∑STE was not associated with final myocardial salvage in patients with pre-PCI TIMI (thrombolysis in myocardial infarction) flow 0/1 (p = 0.24) in contrast to patients with pre-PCI TIMI flow 2/3 (p ≤ 0.001). ConclusionIn patients with STEMI presenting within 12 h of symptom onset, the degree of STE in the ECG before PPCI is a marker of the extent of myocardium at risk that in turn affects the infarct size in patients with pre-PCI TIMI flow 0/1, whereas the degree of STE in patients with pre-PCI TIMI flow 2/3 is a marker of the extent of the myocardium at risk as well as myocardial salvage – both affecting the myocardial damage.