Residual ST-segment elevation at pre-discharge ECG after STEMI: association with long-term prognosis and structural consequences at 6-month CMR

Abstract

Abstract Introduction Residual ST-segment elevation after ST-segment elevation myocardial infarction (STEMI) has been traditionally interpreted as a predictor of left ventricular dysfunction and ventricular aneurism. More recently, it has also been associated with more severe structural consequences in cardiac magnetic resonance (CMR) performed soon after STEMI. However, the implications in terms of long-term prognosis of patients and structural consequences in CMR performed late after STEMI are unclear. Methods Data was obtained from a prospective registry of reperfused STEMI patients. At pre-discharge ECG, sum and maximum ST-segment elevation (mm), ST-segment resolution (%) and the number of Q-leads with residual ST-segment elevation >1 mm (Q-STE) were assessed. 6-month CMR parameters were quantified: left ventricular ejection fraction (LVEF, %), left ventricular end-diastolic and end-systolic volume indexes (LVEDVI and LVESVI, mL/m2), infarct size (IS, % left ventricular mass) and microvascular obstruction (MVO, % left ventricular mass). The primary end-point was major adverse cardiac events (MACE), defined as all-cause death and/or re-admission for acute heart failure, whichever occurred first. Results 488 patients were included. Mean age was 58±12 years, 80.3% were males and smoking was the most prevalent cardiovascular risk factor. During a 7-year mean and median follow-up, 92 MACE were registered (19%), 39 all-cause deaths and 53 re-admission for acute heart failure. Q-STE >1 lead was detected in 172 patients (35%) and it was the most potent ECG predictor of MACE (26% vs 15%, p=0.002). Q-STE was also associated with structural changes at 6-month CMR: larger LVEDVI (87,39±27,47 mL/m2 vs 74,31±24,13 mL/m2) and LVESVI (45,45±25,24 mL/m2 vs 32,53±20,85 mL/m2), less LVEF (50,48±13,95% vs 58,75±12,3%) and larger infarct size (24,91±11,6% vs 14,38±11,41%) (p<0.001 for all comparisons, Figure 1). After adjustment for baseline and ECG characteristics, Q-STE (per lead with >1 mm) was independently associated with a higher risk of long-term MACE (HR 1.24 [CI 95%: 1.09–1.40], p=0.001), depressed (<40%) LVEF (HR 1.26 [CI 95%: 1.02–1.56], p=0.03) and large (>30% left ventricular mass) infarct size (HR 1.34 [CI 95%: 1.08–1.67], p=0.008) at 6-month CMR. Survival free from MACE was lower in patients with >1 lead Q-STE (log-rank=9.07, p=0.003) (Figure 2). Conclusions Residual ST-segment elevation after STEMI represents a widely available predictor of adverse long-term prognosis and late CMR-derived left ventricular remodelling. It could contribute to select patients who would benefit of close monitoring. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Fondos Europeos de Desarrollo Regional FEDERInstituto de Salud Carlos III Figure 1. Structural changes at 6-month CMRFigure 2. Survival free from MACE