Electrocardiographic scores of severity and acuteness of myocardial ischemia predict myocardial salvage in patients with anterior ST-segment elevation myocardial infarction

Electrocardiogram to predict reperfusion success in late presenters with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention

BACKGROUND

Clinical decision-making in patients with ST-segment elevation myocardial infarction (STEMI) presenting beyond 12 h of symptom onset (late presenters) is challenging. However, the electrocardiogram (ECG) may provide helpful information. We investigated the association between three ECG-scores and myocardial salvage and infarct size in late presenters treated with primary percutaneous coronary intervention (primary PCI).

METHODS

Sixty-six patients with STEMI and ongoing symptoms presenting 12-72 h after symptom onset were included. Cardiac magnetic resonance was performed at day 1 (interquartile range [IQR], 1-1) and at follow-up at day 93 (IQR, 90-98). The pre-PCI ECG was analyzed for the presence of pathological QW (early QW) as well as Anderson-Wilkins acuteness score (AW-score), the classic Sclarovsky-Birnbaum Ischemia Grading System (classic SB-IG-score) and a modified SB-IG-score including any T-wave morphologies.

RESULTS

Early QW was associated with a larger myocardium at risk (39 ± 12 versus 33 ± 12; p = 0.030) and final infarct size (20 ± 11 versus 14 ± 9; p = 0.021) as well as a numerical lower final myocardial salvage (0.52 ± 0.19 versus 0.61 ± 0.23; p = 0.09). The association with final infarct size disappeared after adjusting for myocardium at risk. An AW-score < 3 showed a trend towards a larger final infarct size (18 ± 11 versus 11 ± 11; p = 0.08) and was not associated with salvage index (0.55 ± 0.20 versus 0.65 ± 0.30; p = 0.23). The classic and modified SB-IG-score were not associated with final infarct size (modified SB-IG-score, 17 ± 10 versus 21 ± 13; p = 0.28) or final myocardial salvage (0.53 ± 0.20 versus 0.53 ± 0.26; p = 0.96).

CONCLUSION

Of three well-established ECG-scores only early QW and AW-score < 3 showed association with myocardium at risk and infarct size to some extent, but the association with myocardial salvage was weak. Hence, neither of the three investigated ECG-scores are sufficient to guide clinical decision-making in patients with STEMI and ongoing symptoms presenting beyond 12 h of symptom onset.

Terminal QRS Distortion in ST Elevation Myocardial Infarction as a Prediction of Mortality: Systematic Review and Meta-Analysis

Background

Terminal QRS distortion reflects advanced stage and large myocardial infarction predisposing the heart to adverse outcomes. Recent studies suggest that terminal QRS distortion is associated with morbidity and mortality in ST elevation myocardial infarction (STEMI). However, a systematic review and meta-analysis of the literature have not been done.

Objective

We assessed the association between terminal QRS distortion in patients with STEMI and mortality by a systematic review of the literature and a meta-analysis.

Methods

We comprehensively searched the databases of MEDLINE and EMBASE from inception to September 2017. Included studies were published prospective or retrospective cohort studies that compared all-cause mortality in subjects with STEMI with QRS distortion versus those without QRS distortion. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate risk ratios and 95% confidence intervals.

Results

Fifteen studies from January 1993 to May 2015 were included in this meta-analysis involving 7,479 subjects with STEMI (2,906 QRS distortion and 4,573 non-QRS distortion). QRS distortion was associated with increased mortality (pooled risk ratio = 1.81, 95% confidence interval: 1.37-2.40, p < 0.000, I² = 41.6%). Considering the introduction of clopidogrel in 2004, we performed subgroup analyses before and after 2004, and the associated with higher mortality was still present (before 2004, RR 1.75, 95% CI 1.08-2.82, p = 0.022, I² = 66.1%; after 2004, RR 1.96, 95% CI 1.44-2.65, p < 0.001, I² = 0%).

Conclusions

Terminal QRS distortion increased all-cause mortality by 81%. Our study suggests that terminal QRS distortion is an important tool to assess the risk in patients with STEMI.