Predictors and outcome of grade 3 ischemia in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

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.

Automatic electrocardiographic algorithm for assessing severity of ischemia in ST-segment elevation myocardial infarction

BACKGROUND

Terminal QRS distortion on the electrocardiogram (ECG) is a sign of severe ischemia in patients with STEMI and can be quantified by the Sclarovsky-Birnbaum Severity of Ischemia. Due to score complexity, it has not been applied in clinical practice. Automatic scoring of digitally recorded ECGs could facilitate clinical application. We aimed to develop an automatic algorithm for the severity of ischemia.

METHODS

Development set: 50 STEMI ECGs were manually (Manual-score) and automatically (Auto-score) scored by our designed algorithm. The agreement between Manual- and Auto-score was assessed by kappa statistics. Test set: ECGs from 199 STEMI patients were assigned a severity grade (severe or non-severe ischemia) by the Auto-score. Infarct size estimated by median peak Troponin T (TnT) and Creatinine Kinase Myocardial Band (CKMB) was tested between the groups.

RESULTS

The agreement between Manual- and Auto-score was 0.83 ((95% CI 0.55-1.00), p < 0.0001), sensitivity 75% and specificity 100%, PPV 100% and NPV 94.6%. In the test set 152 (76%) patients were male, mean age 61 ± 12 years. The Auto-score designated severe ischemia in 42 (21%) and non-severe ischemia in 157 (79%) patients. Patients with ECG signs of severe vs. non-severe ischemia had significantly higher levels of biomarkers of infarct size. In multiple linear regression, ECG sign of severe ischemia was an independent predictor for higher TnT and CKMB levels.

CONCLUSION

The automatic ECG algorithm for severity of ischemia in STEMI performs adequately for clinical use. Severe ischemia obtained by the Auto-score was associated with biomarker estimated larger infarct size.

Pre-hospital electrocardiographic severity and acuteness scores predict left ventricular function in patients with ST elevation myocardial infarction

OBJECTIVES

System delay (time from first medical contact to primary percutaneous coronary intervention) is associated with heart failure and mortality in patients with ST segment elevation myocardial infarction (STEMI). We evaluated the impact of system delay on left ventricular function (LVF) according to the combination of ischemia severity (Sclarovsky-Birnbaum grades) and acuteness (Anderson-Wilkins scores) in the pre-hospital electrocardiogram (ECG).

METHODS

In a predefined secondary analysis of a prospective study, the severity and acuteness scores were performed on the pre-hospital ECG. Patients were assessed with respect to 4 classifications which were not mutually exclusive: severe ischemia (+SI) or non-severe ischemia (-SI) and acute ischemia (+AI) or non-acute ischemia (-AI). LVF was assessed by global longitudinal strain (GLS) within 48hours of admission. Adjusted linear regression investigated the association of system delay with GLS in each group.

RESULTS

In total 262 patients were eligible for analysis of the ECG, which resulted in 42 (16%) with (+SI, -AI), 110 (42%) with (-SI, -AI), 90 (34%) with (-SI, +AI), and 20 (8%) patients with (+SI, +AI). Although system delay did not differ between groups, patients with severe and non-acute ischemia had the most impaired LVF. System delay correlated weakly with GLS in the entire population (r=0.133, p=0.031), and well with GLS in the (+SI, +AI) group (r=0.456, p=0.04), while there was no correlation in the other groups. By adjusted analysis, system delay predicted impaired GLS only in the (+SI, +AI) group (β=0.578, p=0.002).

CONCLUSION

Pre-hospital risk stratification by ECG identifies patients with acute and severe ischemia who are at increased risk for reduced ventricular function (assessed by GLS) after STEMI. Optimizing reperfusion delays in these patients can therefore be of particular benefit in improving clinical outcome after STEMI.

QRS complex distortion (Grade 3 ischaemia) as a predictor of myocardial damage assessed by cardiac magnetic resonance imaging and clinical prognosis in patients with ST-elevation myocardial infarction

AIMS

Distortion of the terminal portion of the QRS complex (so-called Grade 3 ischaemia, G3I) has been associated with adverse outcomes in ST-elevation myocardial infarction (STEMI) populations. However, the correlation of G3I with infarct size and microvascular injury as defined by cardiac magnetic resonance (CMR) is not well defined. Aim of this study was to assess the relation of G3I with myocardial damage as assessed by CMR and clinical outcomes in STEMI patients.

METHODS AND RESULTS

We analysed the ECGs of 572 consecutive STEMI patients regarding the presence or absence of G3I. CMR was performed within 1 week after infarction for comprehensive assessment of myocardial damage using a standardized protocol. The primary clinical endpoint was major adverse cardiac events (MACE) within 12 months after infarction. G3I was present in 186 (32%) patients. The presence of G3I was associated with larger infarct size (P = 0.01), the presence of late microvascular obstruction (P = 0.05), the presence of intramyocardial haemorrhage (P = 0.04), and impaired myocardial salvage (P = 0.01). G3I was associated with a higher incidence of MACE (P = 0.01) and was identified as an independent predictor of MACE in Cox regression analysis (HR 2.19; 95% CI 1.10 to 4.38, P = 0.03).

CONCLUSION

This largest study to date correlating G3I on the admission ECG with CMR markers of myocardial damage demonstrates that G3I is significantly associated with infarct size, impaired myocardial salvage, and reperfusion injury in a reperfused STEMI population. Moreover, G3I was independently associated with MACE. CLINICALTRIALS.GOV: NCT00712101.

Twenty years of ECG grading of the severity of ischemia

Shortly following an occlusion of an epicardial coronary artery, changes in the surface electrocardiogram (ECG) can be detected. Initially, T waves in leads with their positive poles facing the ischemic zone become positive, tall and symmetrical. Later, ST segment elevation (STE) becomes apparent. If ischemia continues, changes in the terminal portion of the QRS may also be detected. The changes in the terminal portion of the QRS are believed to be caused by prolongation of the electrical conduction in the ischemic zone and reflect severe ischemia due to lack of protection by preconditioning or collateral circulation. Several groups have shown that patients with the QRS changes of grade 3 ischemia have higher mortality, higher incidence of reinfarction and heart failure than patients presenting with only the T and ST changes of grade 2 ischemia, despite equal success in recanalizing the epicardial coronary artery by either thrombolytic therapy or primary percutaneous coronary intervention. Grade 3 ischemia is associated with more rapid progression of necrosis and larger final infarct size. Further studies are needed to better understand the underlying mechanisms that determine the severity of ischemia and how we should use this method based on the standard 12 lead ECG to implement clinical therapeutic decisions.

Relation of angiographic thrombus burden with electrocardiographic grade III ischemia in patients with ST-segment elevation myocardial infarction

BACKGROUND

We aimed to investigate the association between electrocardiographic (ECG) grade III ischemia and angiographic thrombus burden in patients with acute ST-segment elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (pPCI).

METHODS

The study population consisted of 307 patients with STEMI. Baseline ECGs of the patients were analyzed for grade III ischemia; angiographic thrombus burden was assessed by thrombolysis in myocardial infarction thrombus classification.

RESULTS

A total of 108 (35%) patients had low thrombus burden whereas 199 (65%) patients had high thrombus burden. Grade III ischemia was more prevalent in patients with high thrombus burden (25.1% vs 11.1%, P = .004). Only grade III ischemia (odds ratio: 2.59, 95% confidence interval 1.24-5.39, P = .011) and history of coronary artery disease (CAD) were found to be the independent predictors of high thrombus burden.

CONCLUSION

Grade III ischemia on ECG and previous history of CAD were independent predictors of coronary thrombus burden in patients with STEMI who underwent pPCI.