Emergency medical service delays in ST-elevation myocardial infarction: a meta-analysis

Impact of COVID-19 on emergency medical services utilization and severity in the U.S. Upper Midwest

The COVID-19 pandemic has claimed over one million lives in the United States and has drastically changed how patients interact with the healthcare system. Emergency medical services (EMS) are essential for emergency response, disaster preparedness, and responding to everyday emergencies. We therefore examined differences in EMS utilization and call severity in 2020 compared to trends from 2015-2019 in a large, multi-state advanced life support EMS agency serving the U.S. Upper Midwest. Specifically, we analyzed all emergency calls made to Mayo Clinic Ambulance, the sole advanced life support EMS provider serving a large area in Minnesota and Wisconsin, and compared the number of emergency calls made in 2020 to the number of calls expected based on trends from 2015-2019. We similarly compared caller demographics, call severity, and proportions of calls made for overdose/intoxication, behavioral health, and motor vehicle accidents. Subgroup analyses were performed for rural vs. urban areas. We identified 262,232 emergent EMS calls during 2015-2019 and 53,909 calls in 2020, corresponding to a decrease of 28.7% in call volume during 2020. Caller demographics shifted slightly towards older patients (mean age 59.7 [SD, 23.0] vs. 59.1 [SD, 23.7] years; p<0.001) and to rural areas (20.4% vs. 20.0%; p = 0.007). Call severity increased, with 95.3% of calls requiring transport (vs. 93.8%; p<0.001) and 1.9% resulting in death (vs. 1.6%; p<0.001). The proportion of calls for overdose/intoxication increased from 4.8% to 5.5% (p<0.001), while the proportion of calls for motor vehicle collisions decreased from 3.9% to 3.0% (p<0.001). All changes were more pronounced in urban areas. These findings underscore the extent to which the COVID-19 pandemic impacted healthcare utilization, particularly in urban areas, and suggest that patients may have delayed calling EMS with potential implications on disease severity and risk of death.

Effectiveness of STEMI networks with out-of-hospital triage: a systematic review and meta-analysis

INTRODUCTION AND OBJECTIVES

Primary percutaneous coronary intervention (pPCI) is recommended for ST elevation myocardial infarction (STEMI). Countries have designed various STEMI network models to optimize out-of-hospital triage, timely treatment, and patient outcomes. The aim of this study was to evaluate the effectiveness of STEMI network implementation including out-of-hospital triage in improving STEMI case-fatality and long-term mortality, and its effect on the proportion of patients presenting with heart failure, their ischemia time, and time to pPCI.

METHODS

Systematic review and meta-analysis. Searches of PubMed, Scopus, and Web of Science databases covering January 2000 to December 2023, study selection, and data extraction were completed by 3 independent reviewers.

RESULTS

A total of 32 articles were selected. STEMI network implementation with out-of-hospital triage was associated with reductions of 35% in case-fatality (95%CI, -23% to -45%), 27% in long-term mortality (95%CI, -22% to -32%), and in the proportion of patients with Killip III-IV at admission, ischemia, time and time to pPCI (-17%, 95%CI, -35% +6%; -19%, 95%CI, -6% to -31%; -33%, 95%CI, -16% to -47%, respectively). Networks based on emergency transport systems and those involving the entire health system, including primary care centers and hospitals without pPCI capabilities, showed similar effectiveness. Greater effectiveness was observed in urban vs rural areas and high-income vs middle- and low-income countries.

CONCLUSIONS

The implementation of out-of-hospital triage-based STEMI networks is effective in reducing STEMI case-fatality and long-term mortality, independently of the geographic and socioeconomic conditions of the region. Participation of the emergency transport system is the key element of successful networks.

Applications and Performance of Machine Learning Algorithms in Emergency Medical Services: A Scoping Review

OBJECTIVE

The aim of this study was to summarize the literature on the applications of machine learning (ML) and their performance in Emergency Medical Services (EMS).

METHODS

Four relevant electronic databases were searched (from inception through January 2024) for all original studies that employed EMS-guided ML algorithms to enhance the clinical and operational performance of EMS. Two reviewers screened the retrieved studies and extracted relevant data from the included studies. The characteristics of included studies, employed ML algorithms, and their performance were quantitively described across primary domains and subdomains.

RESULTS

This review included a total of 164 studies published from 2005 through 2024. Of those, 125 were clinical domain focused and 39 were operational. The characteristics of ML algorithms such as sample size, number and type of input features, and performance varied between and within domains and subdomains of applications. Clinical applications of ML algorithms involved triage or diagnosis classification (n = 62), treatment prediction (n = 12), or clinical outcome prediction (n = 50), mainly for out-of-hospital cardiac arrest/OHCA (n = 62), cardiovascular diseases/CVDs (n = 19), and trauma (n = 24). The performance of these ML algorithms varied, with a median area under the receiver operating characteristic curve (AUC) of 85.6%, accuracy of 88.1%, sensitivity of 86.05%, and specificity of 86.5%. Within the operational studies, the operational task of most ML algorithms was ambulance allocation (n = 21), followed by ambulance detection (n = 5), ambulance deployment (n = 5), route optimization (n = 5), and quality assurance (n = 3). The performance of all operational ML algorithms varied and had a median AUC of 96.1%, accuracy of 90.0%, sensitivity of 94.4%, and specificity of 87.7%. Generally, neural network and ensemble algorithms, to some degree, out-performed other ML algorithms.

CONCLUSION

Triaging and managing different prehospital medical conditions and augmenting ambulance performance can be improved by ML algorithms. Future reports should focus on a specific clinical condition or operational task to improve the precision of the performance metrics of ML models.

The Barriers to Rapid Reperfusion in Acute ST-Elevation Myocardial Infarction

INTRODUCTION

This study aimed to quantify the contribution of various obstacles to timely reperfusion therapy in acute ST-elevation myocardial infarction (STEMI) and to improve performance in a mixed remote rural/urban region.

METHODS

From November 1, 2020 to April 23, 2021, patients with acute STEMI were prospectively monitored with the critical time intervals, treatment modalities, and outcomes registered. Selected clinical decision-makers in 11 hospitals were appointed as improvement agents and systematically provided with weekly updated information about absolute and relative performance. Suggestions for improvements were invited and shared.

RESULTS

Only 29% of the 146 patients received reperfusion therapy within recommended time limits [prehospital thrombolysis, 2/48; in-hospital thrombolysis, 0/20; primary percutaneous coronary intervention (pPCI), 37/68, with median intervals from the first medical contact of 44, 49, and 133 min, respectively]. Efficiency varied considerably between health trusts: median time from the first medical contact to prehospital thrombolysis ranged from 29 to 54 min (hazard ratio 4.89). The predominant, remediable causes for delays were erroneous tactical choices and protracted electrocardiographic diagnostication, decision-making, and administration of fibrinolytic medication. During the trial, the time to pPCI was non-significantly reduced.

CONCLUSION

We found several targets for system improvements in order to mitigate reperfusion delays along the entire chain of care, regardless of reperfusion modality chosen. More patients should receive prehospital thrombolysis. The most important measures will be training to ensure a more efficient on-site workflow, improved protocols and infrastructure facilitating the communication between first responders and in-hospital clinicians, and education emphasizing prehospital transport times.

CLINICAL TRIALS IDENTIFIER

NCT04614805.

Developing a conceptual model for studying various points of delays and underlying factors in the emergency healthcare system

To review various literature related to emergency healthcarerelated delays and synthesize a conceptual framework for future research. Critical Interpretative Synthesis is employed to analyze and develop themes from selected articles. A total of 25 articles were selected for analysis after the careful selection process. Diseases including acute heart disease, stroke, pneumonia, infections, and gastrointestinal disorders were included. During analysis, three major phases of delays emerged: pre-hospital delay, inhospital delay, and ambulance off-load delay. Various factors, including socioeconomic factors, health system factors, organizational level factors, etc., are related to delays in emergency care settings. The model evolved from this literature analysis is similar to the 3 delays model. This review identified three significant delay segments related to emergency health care management.

Variation in on-scene time of emergency medical services and the extent of the difference of on-scene time between genders: a retrospective population-based registry study in Riyadh Province, Saudi Arabia

OBJECTIVES

To identify the intergender variation of on-scene time (OST) for highly urgent emergency cases conveyed by emergency medical services (EMS) in Saudi Arabia and to assess other predictors of OST and hypothesise for possible factors delaying OST.

DESIGN

A retrospective population-based registry study.

SETTING

Riyadh Province is the largest province in terms of population and the second in terms of geographical area.

PARTICIPANTS

All highly urgent transported patients from the scene to emergency departments, be they medical emergencies or trauma emergencies during 2018.

OUTCOME MEASURE

OST difference between men and women transported by EMS.

RESULTS

In total, 21 878 patients were included for analysis: 33.9% women and 66.1% men. The median OST for women was 22 min (IQR 15-30) and 18 min (IQR 11-26) for men (p<0.001); for medical cases, median OST was 23 min (IQR 16-31) for women compared with 20 min (IQR 13 - 29) for men (p<0.001); for trauma cases, the median OST of both sexes was equal. We found the following additional predictors of OST: factors of emergency type, sex, age category, geographical areas, type of ambulance vehicle and hospital type were all significantly associated with OST in the crude or adjusted analyses. Factors of emergency type, sex, age category, geographical areas, type of ambulance vehicle and hospital type were also significantly associated with the odds of OST of more than 15 min in the crude and adjusted regression analyses.

CONCLUSIONS

The median OST was longer than 15 min for more than half of transported cases. For medical cases, women had a longer median OST than men. Additional predictors associated with prolonged OST were the patient's age, area (ie, urban vs rural), type of ambulance vehicle and season. These findings are hypothesis generating and require further studies.

Impact of a mass media campaign on presentations and ambulance use for acute coronary syndrome

Objective

Between 2009 and 2013, the National Heart Foundation of Australia ran mass media campaigns to improve Australian’s awareness of acute coronary syndrome (ACS) symptoms and the need to call emergency medical services (EMS). This study examined the impact of this campaign on emergency department (ED) presentations and EMS use in Victoria, Australia.

Methods

The Victorian Department of Health and Human Services provided data for adult Victorian patients presenting to public hospitals with an ED diagnosis of ACS or unspecified chest pain (U-CP). We modelled changes in the incidence of ED presentations, and the association between the campaign period and (1) EMS arrival and (2) referred to ED by a general practitioner (GP). Models were adjusted for increasing population size, ACS subtype and demographics.

Results

Between 2003 and 2015, there were 124 632 eligible ED presentations with ACS and 536 148 with U-CP. In patients with ACS, the campaign period was associated with an increase in ED presentations (incidence rate ratio: 1.11; 95% CI 1.07 to 1.15), a decrease in presentations via a GP (adjusted OR (AOR): 0.77; 95% CI 0.70 to 0.86) and an increase in EMS use (AOR: 1.10; 95% CI 1.05 to 1.17). Similar, but smaller associations were seen in U-CP.

Conclusions

The Warning Signs Campaign was associated with improvements in treatment seeking in patients with ACS—including increased EMS use. The increase in ACS ED presentations corresponds with a decrease in out-of-hospital cardiac arrest over this time. Future education needs to focus on improving EMS use in ACS patient groups where use remains low.

The Global Effect of the COVID-19 Pandemic on STEMI Care: A Systematic Review and Meta-analysis

BACKGROUND

The COVID-19 pandemic has affected patients with ST-segment elevation myocardial infarction (STEMI) requiring primary percutaneous coronary intervention (PCI) worldwide. In this review we examine the global effect of the COVID-19 pandemic on incidence of STEMI admissions, and relationship between the pandemic and door to balloon time (D2B), all-cause mortality, and other secondary STEMI outcomes.

METHODS

We performed a systematic review and meta-analysis to primarily compare D2B time and in-hospital mortality of STEMI patients who underwent primary PCI during and before the pandemic. Subgroup analyses were performed to investigate the influence of geographical region and income status of a country on STEMI care. An online database search included studies that compared the aforementioned outcomes of STEMI patients during and before the pandemic.

RESULTS

In total, 32 articles were analyzed. Overall, 19,140 and 68,662 STEMI patients underwent primary PCI during and before the pandemic, respectively. Significant delay in D2B was observed during the pandemic (weighted mean difference, 8.10 minutes; 95% confidence interval [CI], 3.90-12.30 minutes; P = 0.0002; I2 = 90%). In-hospital mortality was higher during the pandemic (odds ratio [OR], 1.27; 95% CI, 1.09-1.49; P = 0.002; I2 = 36%), however this varied with factors such as geographical location and income status of a country. Subgroup analysis showed that low-middle-income countries observed a higher rate of mortality during the pandemic (OR, 1.52; 95% CI, 1.13-2.05; P = 0.006), with a similar but insignificant trend seen among the high income countries (OR, 1.17; 95% CI, 0.95-1.44; P = 0.13).

CONCLUSIONS

The COVID-19 pandemic is associated with worse STEMI performance metrics and clinical outcome, particularly in the Eastern low-middle-income status countries. Better strategies are needed to address these global trends in STEMI care during the pandemic.

STEMI telemedicine for 100 million lives

BACKGROUND

Developing countries struggle to diagnose and treat ST-segment elevation myocardial infarction (STEMI) patients in a timely manner, and subsequent outcomes are suboptimal.

METHODS

The Latin America Telemedicine Network (LATIN) functioned between 2013 to present in four countries-Brazil, Colombia, Mexico, and Argentina. A Hub and Spoke platform was developed to expand access to >100 million population for STEMI care. Patients were triaged at spokes that included small clinics and primary health care centers in remote South American locations. Three telemedicine command sites provided immediate 24/7 electrocardiogram diagnosis and teleconsultation of the STEMI process at 355 centers in four countries.

RESULTS

LATIN Spokes (n = 313) screened up to 30,000 patients per month, and a total of 780,234 patients over the study period. Telemedicine experts diagnosed 8395 (1·1%) with STEMI, of which a total of 3872 (46·1%) were urgently treated at 47 Hubs. A total of 3015 patients (78%) were reperfused with percutaneous coronary intervention. Time-to-telemedicine diagnosis averaged 3·5 min. Average door-to-balloon time improved from 120 to 48 min during the study period and overall STEMI mortality was 5·2%.

INTERPRETATION

Telemedicine transcends boundaries and enables access to millions of patients for STEMI care. With this initiative, LATIN has created a template for reducing disparities in STEMI management between developed and developing countries.

Pre-hospital heparin use for ST-elevation myocardial infarction is safe and improves angiographic outcomes

AIMS

This study aims to evaluate if pre-hospital heparin administration by paramedics is safe and improves clinical outcomes.

METHODS AND RESULTS

Using the multicentre Victorian Cardiac Outcomes Registry, linked with state-wide ambulance records, we identified consecutive patients undergoing primary percutaneous coronary intervention for STEMI between January 2014 and December 2018. Information on thrombolysis in myocardial infarction (TIMI) flow at angiography was available in a subset of cases. Patients receiving pre-hospital heparin were compared to those who did not receive heparin. Findings at coronary angiography and 30-day clinical outcomes were compared between groups. Propensity-score matching was performed for risk adjustment. We identified a total of 4720 patients. Of these, 1967 patients had TIMI flow data available. Propensity-score matching in the entire cohort yielded 1373 matched pairs. In the matched cohort, there was no observed difference in 30-day mortality (no-heparin 3.5% vs. heparin 3.0%, P = 0.25), MACCE (no-heparin 7% vs. heparin 6.2%, P = 0.44), and major bleeding (no-heparin 1.9% vs. heparin 1.4%, P = 0.64) between groups. Propensity-score analysis amongst those with TIMI data produced 552 matched pairs. The proportion of cases with TIMI 0 or 1 flow in the infarct-related artery (IRA) was lower among those receiving pre-hospital heparin (66% vs. 76%, P < 0.001) compared to those who did not.

CONCLUSION 

In this multicentre, propensity-score matched study, the use of pre-hospital heparin by paramedics was safe and is associated with fewer occluded IRAs in patients presenting with STEMI.

Sex Differences in Prehospital Delays in Patients With ST-Segment-Elevation Myocardial Infarction Undergoing Percutaneous Coronary Intervention

Background

Women with ST‐segment–elevation myocardial infarction experience delays in reperfusion compared with men with little data on each time component from symptom onset to reperfusion. This study analyzed sex discrepancies in patient delays, prehospital system delays, and hospital delays.

Methods and Results

Consecutive patients with ST‐segment–elevation myocardial infarction treated with percutaneous coronary intervention across 30 hospitals in the Victorian Cardiac Outcomes Registry (2013–2018) were analyzed. Data from the Ambulance Victoria Data warehouse were used to perform linkage to the Victorian Cardiac Outcomes Registry for all patients transported via emergency medical services (EMS). The primary end point was EMS call‐to‐door time (prehospital system delay). Secondary end points included symptom‐to‐EMS call time (patient delay), door‐to‐device time (hospital delay), 30‐day mortality, major adverse cardiovascular events, and major bleeding. End points were analyzed according to sex and adjusted for age, comorbidities, cardiogenic shock, cardiac arrest, and symptom onset time. A total of 6330 (21% women) patients with ST‐segment–elevation myocardial infarction were transported by EMS. Compared with men, women had longer adjusted geometric mean symptom‐to‐EMS call times (47.0 versus 44.0 minutes; P<0.001), EMS call‐to‐door times (58.1 versus 55.7 minutes; P<0.001), and door‐to‐device times (58.5 versus 54.9 minutes; P=0.006). Compared with men, women had higher 30‐day mortality (odds ratio [OR], 1.38; 95% CI, 1.06–1.79; P=0.02) and major bleeding (OR, 1.54; 95% CI, 1.08–2.20; P=0.02).

Conclusions

Female patients with ST‐segment–elevation myocardial infarction experienced excess delays in patient delays, prehospital system delays, and hospital delays, even after adjustment for confounders. Prehospital system and hospital delays resulted in an adjusted excess delay of 10 minutes compared with men.

Impact of emergency medical service delays on time to reperfusion and mortality in STEMI

Objectives

To explore the relationship between emergency medical service (EMS) delay time, overall time to reperfusion and clinical outcome in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).

Methods

This was a retrospective observational study of 2976 patients with STEMI who presented to EMS and underwent PPCI between January 2014 and December 2017. We performed multivariable logistic models to assess the relationship between EMS delay time and 30-day mortality and to identify factors associated with system delay time.

Results

EMS delay time accounted for the first half of total system delay (median=59 min (IQR=48–77)). Compared with those who survived, those who died had longer median EMS delay times (59 (IQR=11–74) vs 74 (IQR=57–98), p<0.001). EMS delay time was independently associated with a higher risk of mortality (adjusted OR 1.20; 95% CI 1.02 to 1.40, for every 30 min increase), largely driven by complicated patients with cardiogenic shock or cardiac arrest. Independent predictors of longer EMS delay times were older age, women, cardiogenic shock, cardiac arrest, prehospital notification and intensive care management. Although longer EMS delay times were associated with shorter door-to-balloon times, total system delay times increased with increasing EMS delay times.

Conclusion

Increasing EMS delay times, particularly those result from haemodynamic complications, increase total time to reperfusion and are associated with 30-day mortality after STEMI. All efforts should be made to monitor and reduce EMS delay times for timely reperfusion and better outcome.

Factors influencing patient decision delay in activation of emergency medical services for suspected ST-elevation myocardial infarction

OBJECTIVE

The purpose of this study was to identify factors associated with time delay to emergency medical services for patients with suspected ST-elevation myocardial infarction.

METHODS

This observational study involved 1994 suspected ST-elevation myocardial infarction patients presenting to the emergency medical services in Melbourne, Australia, between October 2011-January 2014. Factors associated with delays to emergency medical services call of >1 h and emergency medical services self-referral were analyzed using multivariable logistic regression.

RESULTS

The time of symptom onset was reported for 1819 patients (91.2%), the median symptom onset-to-call time was 52 min (interquartile range=17-176). Of all emergency medical services calls, 17% were referred by healthcare professionals. Compared to self-referred patients, patients who presented to a general practitioner or hospital had higher odds of delay >1 h to emergency medical services activation (adjusted odds ratio 7.76; 95% confidence interval 5.10-11.83; and 8.02; 3.65-17.64, respectively). The other factors associated with emergency medical services call delays of >1 h were living alone, non-English speaking background, a history of substance abuse, less severe symptoms, symptom onset at home and at rest, and self-treatment. Emergency medical services self-referred patients were more likely to be older than 75 years, have a history of ischemic heart disease or revascularization, more severe symptoms, and symptom onset at home, with activity, during the weekends and out-of-hours.

CONCLUSION

Almost one-fifth of emergency medical services calls for suspected ST-elevation myocardial infarction were healthcare referrals, and this was associated with increased delays. A wide range of factors could influence a patient's decision to directly and rapidly seek emergency medical services. More efforts are needed to educate at-risk populations about early self-referral to the emergency medical services.

The Impact of Socioeconomic Factors, Coverage and Access to Health on Heart Ischemic Disease Mortality in a Brazilian Southern State: A Geospatial Analysis

Background

No other disease has killed more than ischemic heart disease (IHD) for the past few years globally. Despite the advances in cardiology, the response time for starting treatment still leads patients to death because of the lack of healthcare coverage and access to referral centers.

Objectives

To analyze the spatial disparities related to IHD mortality in the Parana state, Brazil.

Methods

An ecological study using secondary data from Brazilian Health Informatics Department between 2013-2017 was performed to verify the IHD mortality. An spatial analysis was performed using the Global Moran and Local Indicators of Spatial Association (LISA) to verify the spatial dependency of IHD mortality. Lastly, multivariate spatial regression models were also developed using Ordinary Least Squares and Geographically Weighted Regression (GWR) to identify socioeconomic indicators (aging, income, and illiteracy rates), exam coverage (catheterization, angioplasty, and revascularization rates), and access to health (access index to cardiologists and chemical reperfusion centers) significantly correlated with IHD mortality. The chosen model was based on p < 0.05, highest adjusted R2 and lowest Akaike Information Criterion.

Results

A total of 22,920 individuals died from IHD between 2013-2017. The spatial analysis confirmed a positive spatial autocorrelation global between IDH mortality rates (Moran's I: 0.633, p < 0.01). The LISA analysis identified six high-high pattern clusters composed by 66 municipalities (16.5%). GWR presented the best model (Adjusted R2: 0.72) showing that accessibility to cardiologists and chemical reperfusion centers, and revascularization and angioplasty rates differentially affect the IHD mortality rates geographically. Aging and illiteracy rate presented positive correlation with IHD mortality rate, while income ratio presented negative correlation (p < 0.05).

Conclusion

Regions of vulnerability were unveiled by the spatial analysis where sociodemographic, exam coverage and accessibility to health variables impacted differently the IHD mortality rates in Paraná state, Brazil.

Highlights

The increase in ischemic heart disease mortality rates is related to geographical disparities.The IHD mortality is differentially associated to socioeconomic factors, exam coverage, and access to health.Higher accessibility to chemical reperfusion centers did not necessarily improve patient outcomes in some regions of the state.Clusters of high mortality rate are placed in regions with low amount of cardiologists, income and schooling.

Factors associated with emergency medical service delays in suspected ST-elevation myocardial infarction in Victoria, Australia: A retrospective study

OBJECTIVE

To assess the effect of patient and system characteristics on emergency medical service (EMS) delays prior to arrival at hospital in suspected ST-elevation myocardial infarction (STEMI).

METHODS

This was a retrospective observational study of 1739 patients who presented with suspected STEMI to the EMS in Melbourne, Australia between October 2011 and January 2014. Our primary outcome measure was call-to-hospital time, defined as the time in minutes from emergency call to hospital arrival. We examined the association of patient and system characteristics on call-to-hospital time using multivariable linear regression.

RESULTS

The mean call-to-hospital time was 60.1 min (standard deviation 20.5) and the median travel distance was 13.0 km (interquartile range 7.2-23.1). In the multivariable model, patient characteristics associated with longer call-to-hospital time were age ≥75 years (2.3 min; 95% confidence interval [CI] 0.6-4.0), female sex (1.9 min; 95% CI 0.3-3.4), pre-existing mental health disorder (4.0 min; 95% CI 1.9-6.1) or musculoskeletal disease (2.7 min; 95% CI 1.0-4.4), absence of chest pain (3.0 min; 95% CI 1.1-4.8), and presentation with clinical complications. System factors associated with call-to-hospital time include lower dispatch priority (12.7 min; 95% CI 9.0-16.5) and non-12-lead electrocardiography (ECG) capable ambulance first on scene (4.5 min; 95% CI 3.1-5.8). Patients who were not initially attended by a 12-lead capable ambulance were less likely to receive a 12-lead ECG within 10 min (18.5% vs 71.0%, P < 0.001).

CONCLUSION

A range of patient and system factors may influence EMS delays in STEMI. However, optimising dispatch prioritisation and widespread availability of prehospital 12-lead ECG could lead to substantial reduction in time to treatment.