Timing of ischemic onset estimated from the electrocardiogram is better than historical timing for predicting outcome after reperfusion therapy for acute anterior myocardial infarction: a DANish trial in Acute Myocardial Infarction 2 (DANAMI-2) substudy

Total ischemic time and age as predictors of PCI failure in STEMIs: A systematic review

BACKGROUND

When feasible, primary percutaneous coronary intervention (PCI) is the definitive intervention for ST-elevation myocardial infarction (STEMI). However, cardiac tissue reperfusion is not always achievable after opening the infarct-related artery. Studies have investigated associating factors and scoring for the "no-reflow" phenomenon. This paper aims to systematically establish the predictive values of total ischemic time and patient age as factors of coronary no-reflow in patients undergoing primary PCI.

METHODS

A systematic search was performed using EBSCOhost, including CINAHL Complete, Academic Search Premier, MEDLINE with Full Text, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews. Search results were compiled utilizing Zotero reference manager and exported to Covidence.org for screening, selection, and data extraction by two independent reviewers. The Newcastle-Ottawa Quality Assessment Scale for Cohort Studies was used to evaluate the eight selected studies.

RESULTS

The initial search resulted in 367 articles, with eight meeting the inclusion criteria with a total of 7060 participants. Our systematic review demonstrated that for patients older than 60 years, the odds of the no-reflow phenomenon increased 1.53- 2.53 times. Additionally, patients with increased total ischemic time had 1.147- 4.655 times the odds of no-reflow incidence.

CONCLUSIONS

Patients older than 60 years with a total ischemic time >4-6 h are at higher risk of PCI failure due to the no-reflow phenomenon. Therefore, new guidelines and more research to prevent and treat this physiologic occurrence are essential to improve coronary reperfusion after primary PCI.

The high-risk ECG pattern of ST-elevation myocardial infarction: A substudy of the randomized trial of primary PCI with or without routine manual thrombectomy (TOTAL trial)

BACKGROUND

Useful tools for risk assessment in patients with STEMI are needed. We evaluated the prognostic impact of the evolving myocardial infarction (EMI) and the preinfarction syndrome (PIS) ECG patterns and determined their correlation with angiographic findings and treatment strategy.

METHODS

This substudy of the randomized Trial of Routine Aspiration Thrombectomy with PCI versus PCI Alone in Patients with STEMI (TOTAL) included 7860 patients with STEMI and either the EMI or the PIS ECG pattern. The primary outcome was a composite of death from cardiovascular causes, recurrent MI, cardiogenic shock, or New York Heart Association (NYHA) class IV heart failure within one year.

RESULTS

The primary outcome occurred in 271 of 2618 patients (10.4%) in the EMI group vs. 322 of 5242 patients (6.1%) in the PIS group [AdjustedHR, 1.54; 95% CI, 1.30 to 1.82; p < .001]. The primary outcome occurred in the thrombectomy and PCI alone groups in 131 of 1306 (10.0%) and 140 of 1312 (10.7%) patients with EMI [HR 0.94; 95% CI, 0.74-1.19] and 162 of 2633 (6.2%) and 160 of 2609 (6.1%) patients with PIS [HR 1.00; 95% CI, 0.81-1.25], respectively (p_interaction = 0.679).

CONCLUSIONS

Patients with the EMI ECG pattern proved to have an increased rate of the primary outcome within one year compared to the PIS pattern. Routine manual thrombectomy did not reduce the risk of primary outcome within the different dynamic ECG patterns. The PIS/EMI dynamic ECG classification could help to triage patients in case of simultaneous STEMI patients with immediate need for pPCI.

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.

Annual Trends in Total Ischemic Time and One-Year Fatalities: The Paradox of STEMI Network Performance Assessment

This study is aimed at assessing trends and relations between total ischemic time, the major quality measure of systemic delay, and case-fatality at the population or patient level in response to growing cardiovascular risk and a constant need to shorten the time to treatment in ST-segment elevation myocardial infarction (STEMI). Data from a prospective nationwide registry of STEMI patients admitted between 2006 and 2013 who were treated with primary percutaneous coronary intervention (PCI) were analyzed. Total ischemic time was calculated as the time from the onset of symptoms to primary PCI and was determined as individual and annual. The primary end-point was one-year, all-cause case-fatality. Among the total 70,093 analyzed patients, temporal trends showed significant decrease in total ischemic time (268 vs. 230 minutes, p < 0.001), a worsening of the risk profile and an increase in one-year case-fatality (7.1% vs. 10.8%, p < 0.001). In the multivariate analysis, longer individual total ischemic time was a risk factor for higher mortality (HR 1.024, 95%CI 1.015–1.034, p < 0.001) and remained significant after adjustment for the year of admission. An inverse relation was observed for the median annual time (HR 0.992, 95%CI 0.989–0.994, p < 0.001). Thus, the observed increasing annual trends in case-fatality cannot directly measure the quality of STEMI network performance.

Comparison of the prognostic role of Q waves and inverted T waves in the presenting ECG of STEMI patients

BACKGROUND

Both Q waves and T-wave inversion (TWI) in the presenting ECG are associated with a progressed stage of myocardial infarction, possibly with less potential for myocardial salvage with reperfusion therapy. Combining the diagnostic information from the Q- and T-wave analyses could improve the prognostic work-up in ST-elevation myocardial infarction (STEMI) patients.

METHODS

We sought to determine the prognostic impact of Q waves and TWI in the admission ECG on patient outcome in STEMI. We formed four groups according to the presence of Q waves and/or TWI (Q+TWI+; Q-TWI+; Q+TWI-; Q-TWI-). We studied 627 all-comers with STEMI derived from two patient cohorts.

RESULTS

The patients with Q+TWI+ had the highest and those with Q-TWI- the lowest 30-day and one-year mortality. One-year mortality was similar between Q-TWI+ and Q+TWI-. The survival analysis showed higher early mortality in Q+TWI- but the higher late mortality in Q-TWI+ compensated for the difference at 1 year. The highest peak troponin level was found in the patients with Q+TWI-.

CONCLUSION

Q waves and TWI predict adverse outcome, especially if both ECG features are present. Q waves and TWI predict similar one-year mortality. Extending the ECG analysis in STEMI patients to include both Q waves and TWI improves risk stratification.

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

BACKGROUND

Terminal "QRS distortion" on the electrocardiogram (ECG) (based on Sclarovsky-Birnbaum's Grades of Ischemia Score) is a sign of severe ischemia, associated with adverse cardiovascular outcome in ST-segment elevation myocardial infarction (STEMI). In addition, ECG indices of the acuteness of ischemia (based on Anderson-Wilkins Acuteness Score) indicate myocardial salvage potential. We assessed whether severe ischemia with or without acute ischemia is predictive of infarct size (IS), myocardial salvage index (MSI) and left ventricular ejection fraction (LVEF) in anterior versus inferior infarct locations.

METHODS

In STEMI patients, the severity and acuteness scores were obtained from the admission ECG. Based on the ECG patients were assigned with severe or non-severe ischemia and acute or non-acute ischemia. Cardiac magnetic resonance (CMR) was performed 2-6days after primary percutaneous coronary intervention (pPCI). LVEF was measured by echocardiography 30days after pPCI.

RESULTS

ECG analysis of 85 patients with available CMR resulted in 20 (23%) cases with severe and non-acute ischemia, 43 (51%) with non-severe and non-acute ischemia, 17 (20%) with non-severe and acute ischemia, and 5 (6%) patients with severe and acute ischemia. In patients with anterior STEMI (n=35), ECG measures of severity and acuteness of ischemia identified significant and stepwise differences in myocardial damage and function. Patients with severe and non-acute ischemia had the largest IS, smallest MSI and lowest LVEF. In contrast, no difference was observed in patients with inferior STEMI (n=50).

CONCLUSIONS

The applicability of ECG indices of severity and acuteness of myocardial ischemia to estimate myocardial damage and salvage potential in STEMI patients treated with pPCI, is confined to anterior myocardial infarction.

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.

Agreement between cardiologists and fellows in interpretation of ischemic electrocardiographic changes in acute myocardial infarction

BACKGROUND

Time from symptom onset may not be the best indicator for choosing reperfusion therapy for patients presenting with acute ST-elevation myocardial infarction (STEMI); consequently ECG-based methods have been developed.

METHODS

This study evaluated the inter-observer agreement between experienced cardiologists and junior doctors in identifying the ECG findings of the pre-infarction syndrome (PIS) and evolving myocardial infarction (EMI). The ECGs of 353 STEMI patients were independently analyzed by two cardiologists, one fellow in cardiology, one fellow in internal medicine and a medical student. The last two were given a half-hour introduction of the PIS/EMI-algorithm.

RESULTS

The inter-observer reliability between all the investigators was found to be good according to kappa statistics (κ 0.632-0.790) for the whole study population. When divided into different subgroups, the inter-observer agreements were from good to very good between the cardiologists and the fellow in cardiology (κ 0.652 -0.813) and from moderate to good (κ 0.464-0.784) between the fellow in internal medicine, medical student and the others.

CONCLUSIONS

The PIS and EMI ECG patterns are reliably identified by experienced cardiologists and can be easily adopted by junior doctors.

Correlation of electrocardiogram and regional cardiac magnetic resonance imaging findings in ST-elevation myocardial infarction: a literature review

BACKGROUND

Patients with acute ST-elevation myocardial infarction (STEMI) benefit substantially from emergent coronary reperfusion. The principal mechanism is to open the occluded coronary artery to minimize myocardial injury. Thus the size of the area at risk is a critical determinant of the patient outcome, although other factors, such as reperfusion injury, have major impact on the final infarct size. Acute coronary occlusion almost immediately induces metabolic changes within the myocardium, which can be assessed with both the electrocardiogram (ECG) and cardiac magnetic resonance (CMR) imaging.

METHODS

The 12-lead ECG is the principal diagnostic method to detect and risk-stratify acute STEMI. However, to achieve a correct diagnosis, it is paramount to compare different ECG parameters with golden standards in imaging, such as CMR. In this review, we discuss aspects of ECG and CMR in the assessment of acute regional ischemic changes in the myocardium using the 17 segment model of the left ventricle presented by American Heart Association (AHA), and their relation to coronary artery anatomy.

RESULTS

Using the 17 segment model of AHA, the segments 12 and 16 remain controversial. There is an important overlap in myocardial blood supply at the antero-lateral region between LAD and LCx territories concerning these two segments.

CONCLUSION

No all-encompassing correlation can be found between ECG and CMR findings in acute ischemia with respect to coronary anatomy.

Reperfusion therapy for ST-segment elevation myocardial infarction: has ECG information been underutilized?

This perspective makes a contentious viewpoint that ECG information is underutilized in ST-segment elevation myocardial infarction (STEMI) and the next breakthrough rests on its full utilization. This is to better diagnose difficult cases such as ST changes during bundle branch block, posterior ST elevation and right-sided ST elevation during normal conduction, and aVR ST elevation. More importantly, this is to better characterize the STEMI for tailored reperfusion. The proposal is to develop a system capable of recording from multiple electrodes that one can apply onto oneself, and having analysis coordinated centrally via phone-internet transmission. This provides 'longitudinal' in addition to 'cross-sectional' ECG information. STEMI will be classified on a gray-scale according to its potential size and speed of Q wave evolution. The hypothesis is that large rapidly progressive STEMI is best treated by on-site fibrinolysis with prompt transferral to a percutaneous coronary intervention center; while small stuttering STEMI is best treated by primary percutaneous coronary intervention despite a long delay.

Impact of system delay on infarct size, myocardial salvage index, and left ventricular function in patients with ST-segment elevation myocardial infarction

BACKGROUND

The association between reperfusion delay and myocardial damage has previously been assessed by evaluation of the duration from symptom onset to invasive treatment, but results have been conflicting. System delay defined as the duration from first medical contact to first balloon dilatation is less prone to bias and is also modifiable. The purpose was to evaluate the impact of system delay on myocardial salvage index (MSI) and infarct size in patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention (PCI).

METHODS

In patients with ST-elevation myocardial infarction, MSI and final infarct size were assessed using cardiovascular magnetic resonance. Myocardial area at risk was measured within 1 to 7 days, and final infarct size was measured 90 ± 21 days after intervention. Patients were grouped according to system delay (0 to 120, 121 to 180, and >180 minutes).

RESULTS

In 219 patients, shorter system delay was associated with a smaller infarct size (8% [interquartile range 4-12%], 10% [6-16%], and 13% [8-17%]; P < .001) and larger MSI (0.77 [interquartile range 0.66-0.86], 0.72 [0.59-0.80], and 0.68 [0.64-0.72]; P = .005) for a system delay of up to 120, 121 to 180, and >180 minutes, respectively. A short system delay as a continuous variable independently predicted a smaller infarct size (r = 0.30, P < .001) and larger MSI (r = -0.25, P < .001) in multivariable linear regression analyses. Finally, shorter system delay (0-120 minutes) was associated with improved function (P = .019) and volumes of left ventricle (P = .022).

CONCLUSIONS

A shorter system delay resulted in smaller infarct size, larger MSI, and improved LV function in patients treated with primary PCI. Thus, this study confirms that minimizing system delay is crucial for primary PCI-related benefits.

Acceptable reperfusion delay to prefer primary angioplasty over fibrin-specific thrombolytic therapy is affected (mainly) by the patient's mortality risk: 1 h does not fit all

AIMS

The mortality benefit of primary percutaneous coronary angioplasty (PPCI) is time-dependent. We explored the relationship between risk and PPCI delay, adjusted for the delay at presentation, which leads to equivalent 30-day mortality between PPCI and fibrin-specific thrombolytic therapy (TT).

METHODS AND RESULTS

Sixteen randomized trials were analysed. The mortality rate in the TT arm was interpreted as a proxy for mortality risk. We calculated the PPCI-related delay as the difference between 'door-to-balloon minus door-to-needle' time and PPCI survival benefit as 30-day mortality after TT minus 30-day mortality after PPCI. Baseline mortality risk (P = 0.004), PPCI delay (P = 0.006), and presentation delay (P = 0.03) were correlated with 30-day survival benefit of PPCI. By the regression analysis, the following equation: Z = 0.59X - 0.033Y - 0.0003W - 1.3 (where Z is the absolute reduction in mortality of PPCI over TT, X the mortality risk, Y the PPCI-delay, and W the presentation delay), can be calculated. According to this equation, acceptable angioplasty-related delay shows a wide range based mainly on the different risk profiles.

CONCLUSION

Baseline mortality risk of ST elevation myocardial infarction patients is a major determinant of the acceptable time delay to choose the most appropriate therapy. Although a longer delay lowers the survival advantage of PPCI, a longer PPCI-related delay could be acceptable in high-risk STEMI patients.