Grade 3 ischemia on admission electrocardiogram and chest pain duration predict failure of ST-segment resolution after primary percutaneous coronary intervention for acute myocardial infarction

The prognostic significance of grade of ischemia in the ECG in patients with ST-elevation myocardial infarction: A substudy of the randomized trial of primary PCI with or without routine manual thrombectomy (TOTAL trial)

BACKGROUND

The importance of the grade of ischemia (GI) ECG classification in the risk assessment of patients with STEMI has been shown previously. Grade 3 ischemia (G3I) is defined as ST-elevation with distortion of the terminal portion of the QRS complex in two or more adjacent leads, while Grade 2 ischemia (G2I) is defined as ST-elevation without QRS distortion. Our aim was to evaluate the prognostic impact of the GI classification on the outcome in patients with STEMI.

METHODS

7,211 patients from the TOTAL trial were included in our study. The primary outcome was a composite of cardiovascular death, recurrent myocardial infarction (MI), cardiogenic shock, or New York Heart Association (NYHA) class IV heart failure within one year.

RESULTS

The primary outcome occurred in 153 of 1,563 patients (9.8%) in the G3I group vs. 364 of 5,648 patients (6.4%) in the G2I group (adjusted HR 1.27; 95% CI, 1.04 - 1.55; p=0.022). The rate of cardiovascular death (4.8% vs. 2.5%; adjusted HR 1.48; 95% CI 1.09 - 2.00; p=0.013) was also higher in patients with G3I.

CONCLUSIONS

G3I in the presenting ECG was associated with an increased rate of the composite of cardiovascular death, recurrent MI, cardiogenic shock, or NYHA class IV heart failure within one year compared to patients with G2I. Patients with G3I also had a higher cardiovascular death compared to patients with G2I.

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.

Cyclosporine-insensitive mode of cell death after prolonged myocardial ischemia: Evidence for sarcolemmal permeabilization as the pivotal step

A prominent theory of cell death in myocardial ischemia/reperfusion (I/R) posits that the primary and pivotal step of irreversible cell injury is the opening of the mitochondrial permeability transition (MPT) pore. However, the predominantly positive evidence of protection against infarct afforded by the MPT inhibitor, Cyclosporine A (CsA), in experimental studies is in stark contrast with the overall lack of benefit found in clinical trials of CsA. One reason for the discrepancy might be the fact that relatively short experimental ischemic episodes (<1 hour) do not represent clinically-realistic durations, usually exceeding one hour. Here we tested the hypothesis that MPT is not the primary event of cell death after prolonged (60–80 min) episodes of global ischemia. We used confocal microcopy in Langendorff-perfused rabbit hearts treated with the electromechanical uncoupler, 2,3-Butanedione monoxime (BDM, 20 mM) to allow tracking of MPT and sarcolemmal permeabilization (SP) in individual ventricular myocytes. The time of the steepest drop in fluorescence of mitochondrial membrane potential (ΔΨ_m)-sensitive dye, TMRM, was used as the time of MPT (T_MPT). The time of 20% uptake of the normally cell-impermeable dye, YO-PRO1, was used as the time of SP (T_SP). We found that during reperfusion MPT and SP were tightly coupled, with MPT trending slightly ahead of SP (T_SP-T_MPT = 0.76±1.31 min; p = 0.07). These coupled MPT/SP events occurred in discrete myocytes without crossing cell boundaries. CsA (0.2 μM) did not reduce the infarct size, but separated SP and MPT events, such that detectable SP was significantly ahead of MPT (T_SP -T_MPT = -1.75±1.28 min, p = 0.006). Mild permeabilization of cells with digitonin (2.5–20 μM) caused coupled MPT/SP events which occurred in discrete myocytes similar to those observed in Control and CsA groups. In contrast, deliberate induction of MPT by titration with H₂O₂ (200–800 μM), caused propagating waves of MPT which crossed cell boundaries and were uncoupled from SP. Taken together, these findings suggest that after prolonged episodes of ischemia, SP is the primary step in myocyte death, of which MPT is an immediate and unavoidable consequence.

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.

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.

Distortion of the terminal portion of the QRS is predictor of shock after primary percutaneous coronary intervention for acute myocardial infarction

BACKGROUND

Although invasive management of ST segment elevation myocardial infarction has improved the clinical outcome, cardiogenic shock (CS) remains an important issue. Our purpose was to asses the utility of the initial electrocardiogram in detecting patients who are at increased risk of CS after percutaneous coronary intervention for acute myocardial infarction.

METHODS

We evaluated 508 consecutive patients admitted in our Coronary Unit and treated by primary angioplasty within 12 h of an ST segment elevation myocardial infarction. Patients with cardiogenic shock at admission were excluded. Two groups were defined according to the presence of distortion of the terminal portion of the QRS in two or more adjacent leads (group 1) or the absence of this pattern (group 2).

RESULTS

There were 99 patients (20%) in group 1 and 409 (80%) in group 2. CS developed in 38 patients, 18 in group 1 (18%) and 20 in group 2 (5%), p<0.001. Seventeen patients died in hospital, 6 in group 1 (6%) and 11 in group 2 (3%), p 0.094. Multivariate analysis including clinical, electrocardiographic and angiographic variables showed distortion of the QRS as an independent predictor of cardiogenic shock (odds ratio 3.17, 95% confidence interval 1.44 to 6.96, p 0.004), together with Killip class at admission and TIMI 3 flow after revascularization.

CONCLUSIONS

Distortion of the terminal portion of the QRS complex is a strong predictor of cardiogenic shock in STEMI patients. Close hemodynamic monitoring should be warranted in patients showing this electrocardiographic pattern.