ST-elevation Myocardial Infarction Criteria Research Articles

Detection of brief atrial fibrillation in continuous 12-lead ECG recordings using an algorithm for computerized resting ECG interpretation combined with convolutional neural network for reducing false detections

Existing criteria recommended by ACC/ESC for identifying patients with ST elevation myocardial infarction (STEMI) from the 12-lead ECG perform with high specificity (SP), but low sensitivity (SE). In our previous studies, we found that the SE of ischemia detection can be markedly improved without any loss of SP by calculating, from the 12-lead ECG, ST deviation in 3 “optimal” vessel-specific leads (VSLs). Our original VSLs, based on ΔST body-surface potential maps (BSPMs), have been modified by using the more appropriate J-point BSPMs at peak ischemia (without subtraction of pre-occlusion distributions). The aim of the present study was to compare the performance of these new VSLs with that achieved by the STEMI criteria used in current practice.Two independent datasets of 12-lead ECGs were used: the STAFF III dataset acquired during ischemic episodes caused by balloon inflation in LAD (n = 35), RCA (n = 47), and LCx (n = 17) coronary arteries, and the Glasgow dataset comprising admission 12-lead ECGs of 116 patients who were hospitalized for chest pain and underwent contrast-enhanced cardiac MRI that confirmed AMI in 58 patients (50%).We found that, in the STAFF III dataset, the detection of ischemic state by the STEMI criteria attained SE/SP of 60/97%, whereas SE/SP values of VSLs were 72/98%. In the Glasgow dataset, STEMI criteria yielded SE/SP of 43/98%, whereas the VSLs improved SE/SP to 60/98%. The most significant increase in diagnostic performance appeared in patients with LCx coronary artery occlusion: in STAFF III data (n = 17) SE achieved by STEMI criteria was improved by the VSLs from 35% to 71%; in Glasgow data (n = 12) SE of 31% achieved by STEMI criteria was improved by the VSLs to 69%.In our study population, existing ACC/ESC STEMI criteria complemented by the new VSLs yielded much improved sensitivity of ischemia detection without any detrimental effect on specificity. This finding needs to be corroborated on a larger chest-pain patient population with typical prevalence of acute ischemia presented to the emergency rooms.

Quantitative Flow Ratio for Assessment of Non-Culprit Coronary Artery Lesions During Percutaneous Coronary Intervention (PCI) in 79 Patients Diagnosed with ST-Elevation Myocardial Infarction (STEMI): A Study from a Single Center in Lithuania.

BACKGROUND Approximately half of the patients requiring percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) have additional stenotic coronary artery (CA) lesions in non-infarct-related arteries (non-IRA). This study from a single center in Lithuania aimed to evaluate the use of the quantitative flow ratio (QFR) in assessing non-IRA lesions during PCI in 79 patients diagnosed with STEMI. MATERIAL AND METHODS We prospectively included 105 vessels of 79 patients with worldwide STEMI criteria and ≥1 intermediate (35-75%) lesion in non-IRA between July 2020 and June 2021. For all included patients, QFR analyses were performed twice, during the index PCI (QFR 1) and during a staged procedure ≥3 months later (QFR 2). The QFR analyses were performed with the QAngio-XA 3D and £0.80 were used as cut-off values for PCI. The primary endpoint was a head-to-head numerical agreement between 2 measurements. RESULTS An excellent numerical agreement was found in all investigated lesions, r=0.931, p<0.001, left anterior descending (LAD) r=0.911, p<0.001, left circumflex (LCx) r=0.977, p<0.001, and right coronary artery (RCA) 0.946, p<0.001. Clinical treatment decision-making showed amazing agreement between the 1st and the 2nd QFR analyses, r=0.980, p<0.001. There was 1 disagreement between QFR 1 and QFR 2. CONCLUSIONS The findings from this support previous studies and showed that the QFR is a practical quantitative method to evaluate non-IRA lesions, which in this study included STEMI patients during PCI following occlusive CA stenosis.

Clinical Features of the Aslanger Pattern to Compensate for the Limitation of ST-Elevation Myocardial Infarction (STEMI) Criteria.

ST-elevation is one of the most valuable electrocardiogram findingsto diagnose acute myocardial infarction. However, more than a quarter of acute coronary occlusions are missed by this criterion, causing a delay in revascularization. Therefore, there should be awareness of the limitations of the current criteria and new electrocardiographic findings are required as a diagnostic tool to compensate for them. The Aslanger patternis a specific electrocardiographic finding in acute inferior myocardial infarction with multivessel disease and allows the detection of inferior myocardial infarction that does not show ST-elevation, leading to rapid revascularization. However, in patients with the Aslanger pattern, the hemodynamic characteristics, such as the rate of shock and the use of mechanical circulatory support, as well as prognostic characteristics such as the in-hospital mortality rate, have not yet been clarified. In this study, we retrospectively surveyed the current practice on the basis of ST-elevation myocardial infarction (STEMI) criteria in patients with acute coronary artery occlusion presenting with inferior myocardial infarction. We examined the clinical characteristics of the Aslanger pattern. Based on the STEMI criteria, 71.8% (51/72) of patients were diagnosed with STEMI from an acute electrocardiogram, and 28.2% (21/78) were diagnosed with non-STEMI. As expected, ruling out in all acute coronary artery occlusions using STEMI criteria alone was difficult. A total of 48% of patients with non-STEMI had the Aslanger pattern. In addition, 80% of patients with the Aslanger pattern had multivessel disease, 30% had the use of the mechanical circulatory support, and 20% had in-hospital mortality. This study suggests that the Aslanger pattern is useful not only for diagnosis, but also for predicting hemodynamic collapse and a poor prognosis. Therefore, we should share information on Aslanger pattern with other physicians and use this pattern in daily practice.

Isolated posterior ST-elevation myocardial infarction: the necessity of routine 15-lead electrocardiography: a case series

BackgroundTrue isolated posterior myocardial infarction is an uncommon finding of acute coronary syndrome, with an incidence rate of 3–7%. The prevalence rates of isolated posterior myocardial infarction in men and women are 72% and 28%, respectively. This uncommon finding may be attributed to multiple factors, such as unremarkable changes on 12-lead electrocardiography, a lack of awareness or knowledge, and an absence of diagnostic consensus, which leads to reperfusion delay and poor clinical outcomes.Case summaryHerein, we report three cases of acute myocardial infarction presenting as isolated ST-segment elevation in the posterior leads (V7–V9): Asian men aged 57, 62, and 53 years, who presented with ST-segment depression in V1–V3 that resolved gradually. Coronary angiography revealed a total/critical occlusion of the proximal circumflex coronary artery in all three cases. Routine and accurate interpretations of 15-lead electrocardiography (12-lead with additional V7–V9) resulted in a better sensitivity for isolated posterior myocardial infarction diagnoses, followed by a timely and opportune primary percutaneous coronary intervention.ConclusionsIsolated posterior myocardial infarction is a rare but potentially fatal event that is often accompanied by atypical and subtle changes on 12-lead electrocardiography (especially in the V1–V3 precordial leads) and may remain undetected by physicians. Therefore, the comprehensive and routine application of posterior leads is a crucial addition to the standard diagnosis and management of acute coronary syndrome in patients with subtle ST-segment changes who do not fulfill the criteria for ST-elevation myocardial infarction.

Outcome following late reperfusion with PCI in stable patients with ST-segment elevation myocardial infarction presenting more than 12 hours from onset of symptoms

Abstract Funding Acknowledgements Type of funding sources: None. Introduction 8-40% of patients with acute ST-elevation myocardial infarction (STEMI) present later than 12 hours after symptom onset. According to guidelines these late presenters maintain indication for primary percutaneous coronary intervention (PCI) when there are signs of ongoing ischemia. However, it prevails uncertainty in relation to the best approach in stable late presenters. Aims Describe the profile of stable late STEMI presenters and evaluate the trends of reperfusion decision in the Portuguese reality; compare early term outcomes between patients submitted to emergent primary PCI and those in which it was preferred an initial conservative approach. Methods Retrospective analysis of patients with STEMI presenting ≥12-48h hours after the beginning of the symptoms between October 2010 and December 2019 without evidence of ongoing ischemia, inserted in a national registry of acute coronary syndromes. Patients were dichotomized and compared according to whether or not were submitted to emergent reperfusion based on primary PCI. Results 274 patients were included (2.3% of all STEMI), predominantly men (67.5%), with a mean age of 68±13 years old. Emergent PCI was performed in a minority (15.7%; n=43); even so, coronarography ended up being executed in 61.3% of the admissions, with angioplasty performed in 47.1% of the cases. Right coronary artery was the most common intervened vessel (50.8%). Inotropes were necessary in 4.6% of the patients, with no reports of ventricular assistance device use. Mean ejection fraction was 51±12% with no differences between groups. Patients submitted to emergent PCI (15.7%) had a lower prevalence of atrial fibrillation (0 vs. 9.3%, p=0.04) and had more commonly electrocardiographic criteria for anterior STEMI (64.3% vs. 41.4%, p=0.006). Nitrates were significantly less prescribed at discharge in this subgroup (4.9% vs. 26.8%; p=0.002). Apart from aborted cardiac arrest, that was more prevalent in patients submitted to emergent reperfusion (4.8% vs. 0.9%, p=0.12), it was observed a tendency toward a lower percentage in this subgroup in all other early hard clinical outcomes such as re-infarction (0 vs. 0.4%, p=1.00), mechanical complications (0 vs. 2.2%; p=1.00), sustained ventricular tachycardia (0 vs. 0.9%, p=1.00) and in-hospital death (0% vs. 4.4%, p=0.37). However, none of the differences have reached statistical significance. Conclusion The study shows that, in the Portuguese reality, emergent reperfusion is adopted in only a minority of late stable STEMI patients, with a clear tendency to perform it more frequently in subacute anterior STEMI. Emergent PCI strategy did not show a clear benefit in terms of left ventricular function, risk of re-infarction, arrhythmic and mechanical complications, and in-hospital death. On the other hand, there was apparently a significant advantage of this strategy in ischemic symptom control.

Precordial ST-segment continuum: A variant of the de Winter sign

The vast majority of patients with acute occlusion of the proximal left anterior descending coronary artery (LAD) suffer frank ST-elevation myocardial infarction (STEMI). In contrast, a small but not insignificant minority presents with an electrocardiographic (ECG) pattern termed the “de Winter sign.” The de Winter sign is characterized by upsloping ST depression followed by tall and peaked T waves in the precordial leads. The purpose of this report is to present two cases of acute obstruction of a large wrap-around LAD where the ECGs simultaneously displayed diagnostic criteria both for STEMI and the de Winter sign. We provide possible explanations for this hitherto undescribed phenomenon.

Prevelence of Multivessel Anatomy in Primary Percutaneous Coronary Intervention (PCI) after Acute ST Elevation Myocardial Infarction

Objective: This study aims to determine the frequency of multivessel anatomy in patients with Primary Percutaneous Coronary Intervention (PPCI) after Acute ST-Elevation Myocardial Infarction (STEMI). Methodology: From February 2017 to August 2017, this descriptive cross-sectional study was conducted in National Institute of Cardiovascular Diseases Karachi. P-value&lt;0.05 was considered statistically significant. Patients of Either gender, having comorbid of Diabetic, hypertensive, obese, smokers or ex-smokers, from age ≥35 years and ≤65 years were included for the research subject. However, patients with a previous history of coronary angioplasty or thrombolytic therapy, valvular heart disease, CABG, and all those patients with non-ST-elevation myocardial infarction (NSTEMI) do not meet the criteria for STEMI on electrocardiography were excluded. Result: A total of 97 patients were evaluated with a mean age of 52.5 and standard deviation ±9.76 and weight mean was 68.65±10.86. A significant result was observed with the help of chi-square t-test analysis in the stratification for MVDA. Age was proportionally related to MVDA with a p-value of 0.001. Diabetes Mellitus is another significant factor in association with MVDA with a p-value of 0.001. Hypertension and current smoking status in association with multivessel disease reflect moderate evident significance while gender and ex smoking status have no association with MVDA. Conclusion: Patients with multi-vessel disease comprise the majority of patients undergoing PCI today and will likely remain so. With improved techniques, stents, and adjunctive drugs, outcomes have improved significantly. Keywords: Multivessel Disease Anatomy (MVDA), Standard Modified Cardiovascular Risk Factor (SMuRF), Primary Percutaneous Coronary Artery Intervention (PPCI), Acute ST segment Elevation Myocardial Infarction (STEMI)

Activation of PPCI team in the octogenarian and nonagenarians population: real-world single-centre experience.

ObjectiveAdvancement in healthcare provision has led to increasing octogenarian ST elevation myocardial infarction (STEMI) presentation to hospital for early revascularisation therapies. Limited literature to date exists to suggest octogenarian STEMI population; with majority of trials excluding these age group patients. Due to an ageing population, we expect increasing rates of STEMI in the octogenarian and nonagenarian population in the future. This study seeks to identify the outcomes of patients over the age of 80 presenting with STEMI and determine the factors associated with better or worse outcome.Patients and methodsThis study is a single-centre retrospective observational study involving patients’ age 80 or older presenting with STEMI between January 2014 and December 2019. Patient data were collected by chart review and analysis of the local STEMI database. Standard Bayesian statistics were employed for analysis.Results1301 patients presented with STEMI during this period. 159/1301 (12.2%) were 80 years or older that fulfilled STEMI criteria, 35/159 (22.1%) were medically managed. 107/124 (86.29%) had angiographic evidence of acute total or partial thrombotic occlusion, and 97/107 were treated with primary percutaneous coronary intervention (PPCI). The activation ECG most commonly exhibited an anterior STEMI, while inferior STEMI ECGs had the strongest positive predictive value. PPCI group had a 30-day mortality rate of 20% (p=0.07) and 1-year mortality was 22.4%. Highest mortality was observed with cardiogenic shock, low ejection fraction, higher high sensitivity cardiac troponin T and creatinine at presentation. Conservatively managed patients had significant higher mortality rate (48% vs 22.4%, p=0.005) at 1 year.ConclusionPatients over the age of 80 who present with STEMI and undergo PPCI have a significantly lower mortality rate at 1 year. These patients have a 77.6% survival at 1 year, with 92.4% likelihood of discharge to home (without need for long-term nursing home care). Cardiogenic shock in this group was associated with a 1-year mortality of 87.5%. Despite the advanced age, we suggest favourable outcomes described in the absence of patients presenting with cardiogenic shock.

Time for a new paradigm shift in myocardial infarction.

The ST-elevation myocardial infarction (STEMI)/non-STEMI paradigm per the current guidelines has important limitations. It misses a substantial proportion of acute coronary occlusions (ACO) and results in a significant amount of unnecessary catheterization laboratory activations. It is not widely appreciated how poor is the evidence base for the STEMI criteria; the recommended STEMI cutoffs were not derived by comparing those with ACO with those without and not specifically designed for distinguishing patients who would benefit from emergency reperfusion. This review aimed to discuss the origins, evidence base, and limitations of STEMI/non-STEMI paradigm and to call for a new paradigm shift to the occlusion MI (OMI)/non-OMI.

Human-Computer Agreement of Electrocardiogram Interpretation for Patients Referred to and Declined for Primary Percutaneous Coronary Intervention: Retrospective Data Analysis Study.

BackgroundWhen a patient is suspected of having an acute myocardial infarction, they are accepted or declined for primary percutaneous coronary intervention partly based on clinical assessment of their 12-lead electrocardiogram (ECG) and ST-elevation myocardial infarction criteria.ObjectiveWe retrospectively determined the agreement rate between human (specialists called activator nurses) and computer interpretations of ECGs of patients who were declined for primary percutaneous coronary intervention.MethodsVarious features of patients who were referred for primary percutaneous coronary intervention were analyzed. Both the human and computer ECG interpretations were simplified to either “suggesting” or “not suggesting” acute myocardial infarction to avoid analysis of complex heterogeneous and synonymous diagnostic terms. Analyses, to measure agreement, and logistic regression, to determine if these ECG interpretations (and other variables such as patient age, chest pain) could predict patient mortality, were carried out.ResultsOf a total of 1464 patients referred to and declined for primary percutaneous coronary intervention, 722 (49.3%) computer diagnoses suggested acute myocardial infarction, whereas 634 (43.3%) of the human interpretations suggested acute myocardial infarction (P<.001). The human and computer agreed that there was a possible acute myocardial infarction for 342 out of 1464 (23.3%) patients. However, there was a higher rate of human–computer agreement for patients not having acute myocardial infarctions (450/1464, 30.7%). The overall agreement rate was 54.1% (792/1464). Cohen κ showed poor agreement (κ=0.08, P=.001). Only the age (odds ratio [OR] 1.07, 95% CI 1.05-1.09) and chest pain (OR 0.59, 95% CI 0.39-0.89) independent variables were statistically significant (P=.008) in predicting mortality after 30 days and 1 year. The odds for mortality within 1 year of referral were lower in patients with chest pain compared to those patients without chest pain. A referral being out of hours was a trending variable (OR 1.41, 95% CI 0.95-2.11, P=.09) for predicting the odds of 1-year mortality.ConclusionsMortality in patients who were declined for primary percutaneous coronary intervention was higher than the reported mortality for ST-elevation myocardial infarction patients at 1 year. Agreement between computerized and human ECG interpretation is poor, perhaps leading to a high rate of inappropriate referrals. Work is needed to improve computer and human decision making when reading ECGs to ensure that patients are referred to the correct treatment facility for time-critical therapy.

Low diagnostic yield of ST elevation myocardial infarction amplitude criteria in chest pain patients at the emergency department

Objectives To evaluate the diagnostic yield of the ECG criteria for ST-elevation myocardial infarction in a large cohort of emergency department chest pain patients, and to determine whether extended ECG criteria or reciprocal ST depression can improve accuracy. Design: Observational, register-based diagnostic study on the accuracy of ECG criteria for ST-elevation myocardial infarction. Between Jan 2010 and Dec 2014 all patients aged ≥30 years with chest pain who had an ECG recorded within 4 h at two emergency departments in Sweden were included. Exclusion criteria were: ECG with poor technical quality; QRS duration ≥120 ms; ECG signs of left ventricular hypertrophy; or previous coronary artery bypass surgery. Conventional and extended ECG criteria were applied to all patients. The main outcome was acute myocardial infarction (AMI) and an occluded/near-occluded coronary artery at angiography. Results: Finally, 19932 patients were included. Conventional ECG criteria for ST elevation myocardial infarction were fulfilled in 502 patients, and extended criteria in 1249 patients. Sensitivity for conventional ECG criteria in diagnosing AMI with coronary occlusion/near-occlusion was 17%, specificity 98% and positive predictive value 12%. Corresponding data for extended ECG criteria were 30%, 94% and 8%. When reciprocal ST depression was added to the criteria, the positive predictive value rose to 24% for the conventional and 23% for the extended criteria. Conclusions: In unselected chest pain patients at the emergency department, the diagnostic yield of both conventional and extended ECG criteria for ST-elevation myocardial infarction is low. The PPV can be increased by also considering reciprocal ST depression.

Comparison of the ST-Elevation Myocardial Infarction (STEMI) vs. NSTEMI and Occlusion MI (OMI) vs. NOMI Paradigms of Acute MI.

The current ST-elevation myocardial infarction (STEMI) vs. non-STEMI (NSTEMI) paradigm prevents some NSTEMI patients with acute coronary occlusion from receiving emergent reperfusion, in spite of their known increased mortality compared with NSTEMI without occlusion. We have proposed a new paradigm known as occlusion MI vs. nonocclusion MI (OMI vs. NOMI). We aimed to compare the two paradigms within a single population. We hypothesized that STEMI(-) OMI would have characteristics similar to STEMI(+) OMI but longer time to catheterization. We performed a retrospective review of a prospectively collected acute coronary syndrome population. OMI was defined as an acute culprit and either TIMI 0-2 flow or TIMI 3 flow plus peak troponin T>1.0ng/mL. We collected electrocardiograms, demographic characteristics, laboratory results, angiographic data, and outcomes. Among 467 patients, there were 108 OMIs, with only 60% (67 of 108) meeting STEMI criteria. Median peak troponin T for the STEMI(+) OMI, STEMI(-) OMI, and no occlusion groups were 3.78 (interquartile range [IQR] 2.18-7.63), 1.87 (IQR 1.12-5.48), and 0.00 (IQR 0.00-0.08). Median time from arrival to catheterization was 41min (IQR 23-86min) for STEMI(+) OMI compared with 437min (IQR 85-1590min) for STEMI(-) OMI (p<0.001). STEMI(+) OMI was more likely than STEMI(-) OMI to undergo catheterization within 90min (76% vs. 28%; p<0.001). STEMI(-) OMI patients had significant delays to catheterization but adverse outcomes more similar to STEMI(+) OMI than those with no occlusion. These data support the OMI/NOMI paradigm and the importance of further research into emergent reperfusion for STEMI(-) OMI.

Using ECG-To-Activation Time to Assess Emergency Physicians' Diagnostic Time for Acute Coronary Occlusion.

There is no quality metric for emergency physicians' diagnostic time for acute coronary occlusion. We sought to quantify diagnostic time associated with automated interpretation, classic ST-elevation myocardial infarction (STEMI) criteria, STEMI-equivalents, and subtle occlusions, using electrocardiogram (ECG)-to-activation of catheterization laboratory time. This multicenter retrospective study reviewed all code STEMI patients from the emergency department (ED) with confirmed culprit lesions from January 2016 to December 2018. We measured door-to-ECG (DTE) time and ECG-to-activation (ETA) time. We examined the first ED ECGs to determine whether automated interpretation labeled "STEMI," and they met classic STEMI criteria, STEMI-equivalents, or rules for subtle occlusion. ECG analysis was performed by two emergency physicians blinded to clinical scenario, automated interpretation, and angiographic outcome. There were 177 code STEMIs with culprit lesions, with a median DTE time of 9.0min and a median ETA time of 16.0min. Automated interpretation labeled 55.4% of first ECGs "STEMI" (ETA 6.5min) and 44.6% not "STEMI" (ETA 66min, p<0.0001). Of first ECGs, 63.8% met classic STEMI criteria (ETA 8.0min), 8.5% had STEMI-equivalents (ETA 32.0min, p=0.0026), 16.4% had subtle occlusions (ETA 89.0min, p=0.045), and 11.3% had no diagnostic sign of occlusion (ETA 68.0min, p=0.20). STEMI criteria missed more than one-third of occlusions on first ECG, but most had STEMI-equivalents or rules for subtle occlusion. ETA time can serve as a quality metric for emergency physicians to promote new ECG insights and assess quality improvement initiatives.

Anterior wall ST-elevation myocardial infarction in biventricular paced rhythm

There is alack of evidence on electrocardiographic criteria for ST-elevation myocardial infarction (STEMI) in patients with biventricular paced rhythm. In all previous case reports of STEMI in biventricular paced rhythm, concordant ST-elevations and/or discordant ST-elevations >5 mm were present. This report describes the case of apatient with anterior STEMI and discordant ST-elevations of less than 5 mm during biventricular stimulation with epicardial left ventricular lead and highlights the importance of comparing the electrocardiogram to previous recordings when STEMI is suspected.

LO33: Sharing and teaching electrocardiograms to minimize infarction

Background: Every 30-minute delay to ST-Elevation Myocardial Infarction (STEMI) reperfusion increases one-year mortality by 7.5%. A local audit found that the third of patient electrocardiograms (ECGs) not initially meeting classic STEMI criteria had an ECG-to-Activation (ETA) time of over 90 minutes, more than five times that of classic STEMIs. However, three quarters of “STEMI negative” ECGs met STEMI-equivalent patterns or rules for subtle occlusion, uncovering an opportunity for improvement. Aim Statement: We aimed to reduce ETA time, from initial emergency department (ED) ECG to activation of the cath lab, for patients whose ECGs did not meet classic STEMI criteria, by 30 minutes within one year (i.e. by Dec 2019). Measures &amp; Design: We reviewed all ED Code STEMIs over a 35-month pre-intervention period. Root Cause analyses, including Ishikawa diagram and Pareto chart, led to our Plan-Do-Study-Act cycles: 1) a survey to engage our team; 2) a Grand Rounds presentation as an educational strategy; and 3) weekly web-based feedback to all ED physicians on STEMI-equivalents and subtle occlusions, using recent local cases. Our outcome measures were ETA times, stratified by ECGs not initially meeting STEMI criteria (primary) and those that did (secondary). Our process measures were the number of website visits and page views. Our balancing measure was the proportion of Code STEMIs without culprit lesion. We used Statistical Process Control (SPC) charts with usual special cause variation rules. Evaluation/Results: ETA time for the 37.5% of 56 ECGs that did not meet classic STEMI criteria decreased from 97.5 to 53.7 minutes (min), a 43.8-min absolute decrease (p = 0.037), while those meeting STEMI criteria remained the same (16.5 to 18.2min, p = 0.75). SPC charts did not show special cause variation. There were 2,634 page views (65.9/week) and 1,092 visits (27.3/week), in a group of 80 physicians—i.e. a third of the group each week. There was no change in Code STEMIs without culprit lesions (28.0 % to 23.3%, p = 0.41). Discussion/Impact: We reduced ETA time by 43.8min for the one third of patients with culprit lesions not initially meeting classic STEMI criteria, a magnitude associated with mortality impact. To do so, we used a multi-modal educational strategy including a novel web-based feedback approach to all ED physicians. Local feedback and education on this challenging-to-diagnose subgroup, guided by ETA time as a quality metric, could be replicated in other centres.

MP06: Using electrocardiogram-to-activation time to assess emergency physicians’ diagnostic delay of acute coronary occlusion

Introduction: Electrocardiogram (ECG) diagnosis of acute coronary occlusion has been broadening in recent years, from classic ST-Elevation Myocardial Infarction (STEMI) criteria to STEMI-equivalents and rules for subtle occlusions. However, there is no quality metric focused on emergency physicians’ decision-making. We hypothesized that the time from initial emergency department (ED) ECG to activation of Code STEMI could quantify diagnostic delay associated with automated interpretation, classic STEMI criteria, and other signs of occlusion. Methods: This multi-centre retrospective study reviewed all ED Code STEMI patients with confirmed culprit lesions from two urban academic EDs over a three-year period (Jan 2016 to Dec 2018). We reviewed charts to calculate ECG-to-Activation (ETA) time, measured from the time stamp on the initial ED ECG to the time a Code STEMI was activated (based on the hospital call centre log). We examined ECGs to determine: 1) if automated computer interpretation labelled “STEMI” or not; and 2) whether they met classic STEMI criteria, STEMI-equivalent patterns, or rules for subtle occlusion, based on a priori criteria from published guidelines or studies. All ECGs were reviewed by the lead author (JTTM) and those not obviously meeting classic STEMI criteria were independently reviewed by the other author. Results: There were 180 Code STEMIs from the ED with culprit lesions, including 177 with complete information. Average ETA time was 46.5 minutes (95% Confidence Interval [CI] 36.3-56.7min). Automated interpretation labelled 55.4% of initial ECGs as “STEMI” (ETA 13.9 min, 95%CI 9.8-18.0min), and 44.6% not as “STEMI” (ETA 86.9min, 95%CI 67.9-105.9min). Initial ECGs included 62.1% with classic STEMI criteria (ETA 17.3min, 95%CI 12.8-21.8min), 11.3% with STEMI-equivalents (ETA 49.5min, 95%CI 29.5-69.5min), 18.1% with subtle occlusions (ETA 118.3min, 95%CI 81.5-155.1min) and 8.5% with no initial sign of occlusion (ETA 102.9min, 95%CI 53.9-151.9min). Inter-rater reliability was very good (Cohen's kappa 0.84). Conclusion: Over 90% of Code STEMI patients with culprit lesions had initial ECGs diagnostic of acute coronary occlusion, but automated interpretation and classic STEMI criteria only identified 55.4% and 62.1%, respectively. STEMI-equivalents and subtle occlusions were associated with significant diagnostic delays. ETA time can serve as a quality metric for emergency physicians and may help guide ED quality improvement initiatives.

P101: Seasonal variations in modes of presentation in ST elevation myocardial infarction

Introduction: For patients with ST-elevation myocardial infarction (STEMI), time is myocardium. The sooner STEMI patients receive a definitive intervention, the better their outcomes. The first point of contact with the healthcare system for STEMI patients is either via Emergency Medical Services (EMS), or self-transportation to an Emergency Department (ED). Despite a reduced time to definitive intervention, STEMI patients who use EMS have increased mortality compared to those who self-transport. In an effort to optimize STEMI care pathways, we characterized variations in modes of presentation of STEMI patients in our region. Methods: This study used a retrospective cohort design from a regional STEMI registry. Patients presenting to Hamilton Health Sciences between January 1, 2016, and December 31, 2018 meeting STEMI criteria were included in our analyses. Self-transport patients were analyzed from two academic EDs in Hamilton, Ontario. One hospital was PCI capable and the other, non-PCI capable. Patients transferred from other health regions were excluded from our analyses. Dichotomous variables were compared using χ2 tests. Group means were compared using the Student t-test. Results: Eight hundred and seventy-one patients were included in the analysis, including 675 EMS users, and 196 self-transporting to EDs. Patients self-transporting to EDs were younger (61.5 v. 64.6 y, p &lt; 0.002) and more often male (82.6 v. 69.2%, p &lt; 0.0002) compared to EMS users. There was a non-significant trend towards an increased rate of all STEMI patients self-transporting in the summer months compared to the winter (63 of 215 in summer v. 41 of 185 in winter, 29.3 v. 22.2%, p = 0.10). Comparative analysis between both hospitals yielded an increased rate of self-transportation to the PCI-capable hospital in the summer months compared to winter (46 v. 28, 23.2 v. 16.3%, p = 0.09), but not the other hospital (18 v. 13, 10.6 v. 8.3%, p = 0.57). The majority of self-transporting patients came from postal codes bordering each hospital, and the different rates of self-transportation between hospitals were not associated with recent specialist follow up at those sites. Conclusion: Seasonal trends in modes of presentation in STEMI patients may present an opportunity to optimize STEMI care pathways through resource utilization and patient education. A larger dataset and possible multicenter analysis should be done to determine if significance is obtained with larger sample size.

Evaluation of Spodick's Sign and Other Electrocardiographic Findings as Indicators of STEMI and Pericarditis.

Patients with ST elevation on electrocardiogram (ECG) could have ST elevation myocardial infarction (STEMI) or pericarditis. Spodick's sign, a downsloping of the ECG baseline (the T-P segment), has been described, but not validated, as a sign of pericarditis. This study estimates the frequency of Spodick's sign and other findings in patients diagnosed with STEMI and those with pericarditis. In this retrospective review, we selected charts that met prospective definitions of STEMI (cases) and pericarditis (controls). We excluded patients whose ECGs lacked ST elevation. An authority on electrocardiography reviewed all ECGs, noting the presence or absence of Spodick's sign, ST depression (in leads besides V1 and aVR), PR depression, greater ST elevation in lead III than in lead II (III>II), abrupt take-off of ST segment (the RT checkmark sign), and upward or horizontal ST convexity. We quantified strength of association using odds ratio (OR) with 95% confidence interval (CI). One hundred and sixty-five patients met criteria for STEMI and 42 met those for pericarditis. Spodick's sign occurred in 5% of patients with STEMI (95% CI 3-10%) and 29% of patients with pericarditis (95% CI 16-45%). All other findings statistically distinguished STEMI from pericarditis, but ST depression (OR 31), III>II (OR 21), and absence of PR depression (OR 12) had the greatest OR values. Spodick's sign is statistically associated with pericarditis, but it is seen in 5% of patients with STEMI. Among other findings, ST depression, III>II, and absence of PR depression were the most discriminating.

463 Comparison of Clinician and Algorithm ECG Interpretation in ACS

Timely and accurate interpretation of the ECG is critical for identifying ST elevation myocardial infarction (STEMI) and Ischaemia and determining appropriate management. To compare approaches in ECG interpretation in detecting Rhythm, Ischaemia and presence of STEMI (or Equivalent) to determine safety and transferability to practice. 50 Adult ECGs were randomly selected from the Hunter New England Health ECG storage system. The ECGs were reported independently by a Cardiology Clinical Nurse Consultant and a Senior Cardiologist, and compared to machine-generated ECG algorithms. Concordance between readers was assessed. Reporting demonstrated concordance between the clinicians, however there was some variation with the ECG algorithms observed. Both clinicians reported the presence of ST elevation in 3 ECGs (not meeting STEMI criteria) detected by the algorithm in just one case. 4 ECGs were reported by both clinicians as Left bundle branch block (LBBB), detected in only 2 by the algorithm. 5 ECGs were reported by both clinicians as ischaemic, detected by the algorithm in 3 cases. All remaining ECGs were reported as normal, consistent across the 3 reporting methods. There is consistency across Senior Cardiology Nursing and Medical Clinicians in accurately detecting Ischaemia, ST elevation and STEMI equivalent patterns on the ECG in this small cohort. There is variation between certain ECG algorithms and clinician findings. Further evaluation will assist in informing transferability to clinical practice.

Safety of Tiered-Dispatch for 911 Calls for Abdominal Pain.

IntroductionMany dispatch systems send Advanced Life Support (ALS) resources to patients complaining of abdominal pain even though the majority of these incidents require only Basic Life Support (BLS). With increasing 911-call volume, resource utilization has become more important to ensure that ALS resources are available for time-critical emergencies. In 2015, a large, urban fire department implemented an internally developed, tiered-dispatch system. Under this system, patients reporting a chief complaint of abdominal pain received the closest BLS ambulance dispatched alone emergency if located within three miles of the incident. The objective of this study was to determine the safety of BLS-only dispatch to abdominal pain by determining the frequency of time-sensitive events.MethodsThis was a retrospective review of electronic health records of one emergency medical service provider agency from May 2015–2018. Inclusion criteria were a chief complaint of abdominal pain from a first- or second-party caller, age over 15, and the patient was reported to be alert and breathing normally. The primary outcome was the prevalence of time-sensitive events, including cardiopulmonary resuscitation (CPR), defibrillation, or airway management. Secondary outcomes were hypotension (systolic blood pressure < 90 mmHg); or a prehospital 12 lead-electrocardiogram (ECG) demonstrating ST-elevation myocardial infarction (STEMI) criteria or a wide complex arrhythmia. Descriptive statistics were used.ResultsDuring the study period, there were 1,220,820 EMS incidents, of which 33,267 (2.72%) met inclusion criteria. The mean age was 49.9 years (range 16–111, standard deviation [SD] 19.6); 14,556 patients (56.2%) were female. Time-sensitive events occurred in seven cases (0.021%), mean age was 75.3 years (range 30–86, SD18.7); 85.7% were female. Airway management was required in seven cases (0.021%), CPR in six cases (0.018%), and defibrillation in one case (0.003%). Two of the seven (28.6%) cases involved dispatch protocol deviations. Hypotension was present in 240 (0.72%) cases; six (0.018%) cases had 12-lead ECGs meeting STEMI criteria; and no cases demonstrated wide complex arrhythmia.ConclusionAmong adult 911 patients with a dispatch chief complaint of abdominal pain, time-sensitive events were exceedingly rare. Dispatching a BLS ambulance alone appears to be safe.