Real-time paramedic compared with blinded physician identification of ST-segment elevation myocardial infarction: results of an observational study

A Novel Algorithm for Improving the Prehospital Diagnostic Accuracy of ST-Segment Elevation Myocardial Infarction

INTRODUCTION

Early detection of ST-segment elevation myocardial infarction (STEMI) on the prehospital electrocardiogram (ECG) improves patient outcomes. Current software algorithms optimize sensitivity but have a high false-positive rate. The authors propose an algorithm to improve the specificity of STEMI diagnosis in the prehospital setting.

METHODS

A dataset of prehospital ECGs with verified outcomes was used to validate an algorithm to identify true and false-positive software interpretations of STEMI. Four criteria implicated in prior research to differentiate STEMI true positives were applied: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. The test characteristics were calculated and regression analysis was used to examine the association between the number of criteria included and test characteristics.

RESULTS

There were 44,611 cases available. Of these, 1,193 were identified as STEMI by the software interpretation. Applying all four criteria had the highest positive likelihood ratio of 353 (95% CI, 201-595) and specificity of 99.96% (95% CI, 99.93-99.98), but the lowest sensitivity (14%; 95% CI, 11-17) and worst negative likelihood ratio (0.86; 95% CI, 0.84-0.89). There was a strong correlation between increased positive likelihood ratio (r2 = 0.90) and specificity (r2 = 0.85) with increasing number of criteria.

CONCLUSIONS

Prehospital ECGs with a high probability of true STEMI can be accurately identified using these four criteria: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. Applying these criteria to prehospital ECGs with software interpretations of STEMI could decrease false-positive field activations, while also reducing the need to rely on transmission for physician over-read. This can have significant clinical and quality implications for Emergency Medical Services (EMS) systems.

Electrocardiographic interpretation by emergency medical services professionals in Saudi Arabia: A cross sectional study

BACKGROUND

Management of acute myocardial infarction (AMI) and cardiac arrhythmias in prehospital settings is largely determined by providers of emergency medical services (EMS) who can proficiently interpret the electrocardiography (ECG). The aim of this study was to assess the ECG competency of EMS providers in Saudi Arabia.

METHODS

Between Aug and Sep 2022, we invited all EMS providers working for the Saudi Red Crescent Authority in Makkah, Riyadh, and Sharqiyah regions to complete a cross-sectional survey. The survey was used to assess the ability of EMS providers to interpret 12 ECG strips. Characteristics and ECG competency were summarized using descriptive statistics. Differences in ECG competency across paramedics with lower and higher qualifications were assessed.

RESULTS

During the study period, 231 participants completed the survey, and all were included. The overall mean age was 33.4, and most participants were male (94.8%). Nearly half of the participants were paramedics with an associate degree and 46.4% were paramedics with higher degrees. The average rate of correct answers to the 12 ECG strips was 43.3% (95% CI: 35.4%, 51.3%). Atrial flutter, ventricular fibrillation, atrial fibrillation, 3rd degree heart block, and ventricular tachycardia were identified by 52.8%, 60.2%, 42.0%, 40.7%, and 49.4% of the participants, respectively. The strip with an AMI was identified by 41.1%, while a pathological Q wave and ventricular extrasystole were identified by 19.1% and 24.7%, respectively. Paramedics with higher qualifications were as 28.0%-61.0% more likely to correctly interpret the 12 ECG strips compared to those with an associate degree (p-value across all variables was ≤ 0.001).

CONCLUSION

While the majority of participants in our region were unable to correctly answer the 12 ECG questionnaire, paramedics with higher qualifications were. Our study indicates that there is a need for evidenced-based ECG curricula targeting different levels of EMS professionals.

Paramedic Ability in Interpreting Electrocardiogram with ST-segment Elevation Myocardial Infarction (STEMI) in Saudi Arabia

Objective

To evaluate paramedic ability in recognizing 12-lead Electrocardiogram (ECG) with ST-segment Elevation myocardial infarction (STEMI) in Saudi Arabia.

Methods

This is a quantitative exploratory cross-sectional study using an electronic survey of paramedics was conducted between June and September 2021. The survey included demographics, educational and clinical experiences, and multiple 12-lead ECG strip questions to assess participants’ ability to recognize STEMI. We reported the overall sensitivity, specificity, and correct proportions with 95% Confidence Intervals (CI).

Results

Eighty-four paramedics completed the survey, and 65% of them were between 24 and 29 years old, with a median, of three years of field experience. Overall sensitivity and specificity were 58.39% (95% CI, 50.4% to 66.1%) and 29.01% (95% CI, 25.15% to 33.1%), respectively. In total, 67.1% correctly identified inferior STEMI, whereas only 50% correctly identified lateral STEMI. Both STEMIs were correctly identified by 41%, and the majority misinterpreted STEMI mimics (ECG rhythms with similar ECG morphology to STEMI). The proportion who correctly recognized left bundle branch block was 14.8%, pericarditis was 10.9%, and ventricular pacing was 1.4%. However, almost third of participants correctly identified right bundle branch block (32.9%) and left ventricle hypertrophy (30.7%). Overall, there was no correlation between the correct ECG interpretation of STEMIs and educational and clinical experiences.

Conclusion

Paramedics were able to identify STEMI events in prehospital settings with moderate sensitivity and low specificity with limited ability to differentiate between STEMI and STEMI mimics. Therefore, additional training in ECG interpretation could improve their clinical decision-making, and to ensure that proper care and treatment is provided. Further research on a large, representative sample of paramedics across the country could provide more definitive evidence to establish a greater degree of accuracy in detecting STEMI in prehospital settings.

Systematic Review and Meta-Analysis of Diagnostic Accuracy to Identify ST-Segment Elevation Myocardial Infarction on Interpretations of Prehospital Electrocardiograms

Background: The aim of this study was to assess and discuss the diagnostic accuracy of prehospital ECG interpretation through systematic review and meta-analyses.

Methods and Results: Relevant literature published up to July 2020 was identified using PubMed. All human studies of prehospital adult patients suspected of ST-segment elevation myocardial infarction in which prehospital electrocardiogram (ECG) interpretation by paramedics or computers was evaluated and reporting all 4 (true-positive, false-positive, false-negative, and true-negative) values were included. Meta-analyses were conducted separately for the diagnostic accuracy of prehospital ECG interpretation by paramedics (Clinical Question [CQ] 1) and computers (CQ2). After screening, 4 studies for CQ1 and 6 studies for CQ2 were finally included in the meta-analysis. Regarding CQ1, the pooled sensitivity and specificity were 95.5% (95% confidence interval [CI] 82.5–99.0%) and 95.8% (95% CI 82.3–99.1%), respectively. Regarding CQ2, the pooled sensitivity and specificity were 85.4% (95% CI 74.1–92.3%) and 95.4% (95% CI 87.3–98.4%), respectively.

Conclusions: This meta-analysis suggests that the diagnostic accuracy of paramedic prehospital ECG interpretations is favorable, with high pooled sensitivity and specificity, with an acceptable estimated number of false positives and false negatives. Computer-assisted ECG interpretation showed high pooled specificity with an acceptable estimated number of false positives, whereas the pooled sensitivity was relatively low.

Advanced Life Support for out-of-hospital Chest Pain: The Opals Study

Context: As many as 14% of patients transported by ambulance with chest pain die prior to hospital discharge. To date, no high-quality controlled trials have revealed that prehospital advanced life support interventions affect survival for these patients.Objective: The Ontario Prehospital Advanced Life Support (OPALS) Study assessed the effect of adding an advance life support service to an existing basic life support emergency medical service program, on the rate of mortality and morbidity for patients with out-of-hospital chest pain.Design: Controlled clinical trial comparing survival for 9 months before and 9 after instituting an advanced life support program.Setting: Thirteen urban and suburban Ontario communities (populations ranging from 30,000 to 750,000; total, 2.5 million).Patients: All adult patients with a primary complaint of chest pain and transported by paramedics to the emergency department.Intervention: Paramedics were trained in standard advanced life support, which includes endotracheal intubation, intravenous furosemide and morphine, oral ASA, and sublingual NTG. Emergency medical services within each community had to meet predefined criteria in order to qualify for the advanced life support phase.Main Outcome Measure: Survival to hospital discharge.Results: Overall, 12,168 patients were enrolled in either the basic life support phase (N = 5,788) or the advanced life support phase (N = 6,380). The rate of mortality significantly decreased from 4.3% in the basic life support phase to 3.2% in the advanced life support phase (absolute change 1.1, 95% CI 0.4-1.8, P = 0.0013). We also demonstrated a decrease in mortality for the subgroup of patients with a discharge diagnosis of myocardial infarction (13.1 percent vs 8.2 percent, P = 0.002).Conclusions: The addition of a prehospital advanced life support program to an existing basic life support emergency medical service was associated with a significant decrease in the mortality rate among patients complaining of chest pain. Future research should clarify the most effective interventions and target specific populations.ClinicalTrials.gov Identifier: NCT00212953.

Present and Future Status of Cardiovascular Emergency Care System in Urban Areas of Japan - Importance of Prehospital 12-Lead Electrocardiogram

Acute cardiovascular disease, such as acute myocardial infarction and aortic disease, can lead to a serious life-threatening state within minutes to hours, so early accurate diagnosis, and appropriate treatment without delay are essential. To provide high-quality and timely treatment, 24-h availability of medical staff and cardiologists, as well as a cardiac catheterization laboratory are needed. In Japan, the number of patients with acute cardiovascular disease is increasing with the aging population and westernization of lifestyle; however, workstyle reforms for physicians, including a policy to limit overtime work, have been legislated. Under these conditions, it is necessary to centralize hospitals that treat cardiovascular emergency diseases as high-volume centers and build a patient triage system for allocating patients before hospital arrival. The prehospital 12-lead electrocardiogram (ECG) plays a central role in prehospital diagnosis and triage, and its importance will increase in future. We discuss the current and future state of the cardiovascular emergency medical care system utilizing prehospital 12-lead ECG in urban areas of Japan.

What Adult Electrocardiogram (ECG) Diagnoses or Findings are Most Important for Advanced Care Paramedics to Know?

Introduction: The interpretation of electrocardiograms (ECGs) is an essential competency in modern paramedicine. Although educational guidelines for paramedic ECG interpretation exist, they are broad, not evidence-based, and lack prioritization in a prehospital clinical context. We conducted this study to gain consensus among stakeholders (EMS physicians, paramedic educators, and paramedic clinicians) regarding which ECG diagnoses or findings are most important for a practising advanced care paramedic to know. 

Methods: This study was an internet-based Delphi survey. We purposefully sampled participants in pairs (physician/paramedic) from all 10 Canadian provinces. Individuals rated a previously developed comprehensive list of emergency ECG diagnoses or findings on the importance of paramedic recognition and impact on prehospital care using a 4-point Likert scale. The consensus was achieved with a minimum of 75% agreement on Likert rating for a single diagnosis or finding during survey rounds one to three. When consensus was not reached, stability was defined as a shift of individual ratings between rounds of 20% or less.

Results: All 20 participants completed the first and second rounds of the survey, and 17 (85%) completed three rounds. Overall, 32 (26.4%) of 121 potentially important ECG diagnoses or findings reached consensus, 2 (1.7%) reached stability and 87 (71.9%) reached neither consensus nor stability. Twenty-one (17.4%) diagnoses or findings were considered “Very Important”, six (4.9%) “Important”, and five (4.1%) “Minimally Important”. In the first round of the survey, the mean rating of the importance of a paramedic knowing a specific ECG diagnosis or finding was lower in the physician group than the paramedic group on 85 (72%) of 118 initial diagnoses or findings.

Conclusion: We have created a list of ECG diagnoses or findings prioritized for the prehospital context that may assist paramedic educators in focusing on educational interventions. Many ECG diagnoses or findings failed to reach consensus or stability, demonstrating potential disagreement regarding clinical expectations for ECG knowledge among paramedics or physicians.

Pre-hospital triage performance and emergency medical services nurse's field assessment in an unselected patient population attended to by the emergency medical services: a prospective observational study

BACKGROUND

In Sweden, the rapid emergency triage and treatment system (RETTS-A) is used in the pre-hospital setting. With RETTS-A, patients triaged to the lowest level could safely be referred to a lower level of care. The national early warning score (NEWS) has also shown promising results internationally. However, a knowledge gap in optimal triage in the pre-hospital setting persists. This study aimed to evaluate RETTS-A performance, compare RETTS-A with NEWS and NEWS 2, and evaluate the emergency medical service (EMS) nurse's field assessment with the physician's final hospital diagnosis.

METHODS

A prospective, observational study including patients (≥16 years old) transported to hospital by the Gothenburg EMS in 2016. Three comparisons were made: 1) Combined RETTS-A levels orange and red (high acuity) compared to a predefined reference emergency, 2) RETTS-A high acuity compared to NEWS and NEWS 2 score ≥ 5, and 3) Classification of pre-hospital nurse's field assessment compared to hospital physician's diagnosis. Outcomes of the time-sensitive conditions, mortality and hospitalisation were examined. The statistical tests included Mann-Whitney U test and Fisher's exact test, and several binary classification tests were determined.

RESULTS

Overall, 4465 patients were included (median age 69 years; 52% women). High acuity RETTS-A triage showed a sensitivity of 81% in prediction of the reference patient with a specificity of 64%. Sensitivity in detecting a time-sensitive condition was highest with RETTS-A (73%), compared with NEWS (37%) and NEWS 2 (35%), and specificity was highest with NEWS 2 (83%) when compared with RETTS-A (54%). The negative predictive value was higher in RETTS-A (94%) compared to NEWS (91%) and NEWS 2 (92%). Eleven per cent of the final diagnoses were classified as time-sensitive while the nurse's field assessment was appropriate in 84% of these cases.

CONCLUSIONS

In the pre-hospital triage of EMS patients, RETTS-A showed sensitivity that was twice as high as that of both NEWS and NEWS 2 in detecting time-sensitive conditions, at the expense of lower specificity. However, the proportion of correctly classified low risk triaged patients (green/yellow) was higher in RETTS-A. The nurse's field assessment of time-sensitive conditions was appropriate in the majority of cases.

Paramedic-Delivered Fibrinolysis in the Treatment of ST-Elevation Myocardial Infarction: Comparison of a Physician-Authorized versus Autonomous Paramedic Approach

Background: For those patients who receive fibrinolysis in the treatment of ST-elevation myocardial infarction (STEMI), early treatment, i.e., within 2 hours of symptom onset, confers the greatest clinical benefit. This rationale underpins paramedic-delivered fibrinolysis in the prehospital setting. However, the current New Zealand approach requiring paramedics to first gain physician authorization, has proved inefficient and time consuming, particularly due to technological failings. Therefore, this study aimed to trial a new autonomous paramedic-delivered fibrinolysis model, examining the impact on time-to-treatment, paramedic diagnostic accuracy and patient outcomes. Methods: Utilizing a prospective observational approach, over a 24-month period, paramedics identified patients with a clinical presentation and electrocardiogram features consistent with STEMI, and initiated fibrinolysis. These patients were compared to a historic cohort who received fibrinolysis by paramedics within the same regions but following physician authorization. The main outcome measures were pain-to-needle (PTN) time and accuracy of paramedic diagnosis. A secondary end-point was 30-day and 6-month mortality and hospital length of stay (LOS). Results: A total of 174 patients received fibrinolysis (mean age, 64 years, SD ± 11.2). Median PTN time was 87 minutes (IQR = 58) for the historic cohort (n = 96), versus 65 minutes (IQR = 31) for the experimental cohort (n = 78), (p = 0.007). Autonomous paramedic diagnosis showed a sensitivity of 96% (95% CI 89-99) and specificity of 91% (95% CI 76-98). A significant reduction in both 30-day mortality and hospital LOS was observed among the experimental cohort (p = 0.04 and <0.001, respectively). No significant difference was observed between groups in terms of 6-month mortality. Conclusions: Prehospital fibrinolysis provided autonomously by paramedics without direct physician oversight is safe and feasible. Moreover, this independent approach can significantly improve time-to-treatment, resulting in short term mortality benefit and reduced hospital LOS.

A Novel Algorithm for Improving the Diagnostic Accuracy of Prehospital ST-Elevation Myocardial Infarction

INTRODUCTION

ST-segment elevation myocardial infarction (STEMI) is a time-sensitive entity that has been shown to benefit from prehospital diagnosis by electrocardiogram (ECG). Current computer algorithms with binary decision making are not accurate enough to be relied on for cardiac catheterization lab (CCL) activation.

HYPOTHESIS

An algorithmic approach is proposed to stratify binary STEMI computerized ECG interpretations into low, intermediate, and high STEMI probability tiers.

METHODS

Based on previous literature, a four-criteria algorithm was developed to rule out/in common causes of prehospital STEMI false-positive computer interpretations: heart rate, QRS width, ST elevation criteria, and artifact. Prehospital STEMI cases were prospectively collected at a single academic center in Salt Lake City, Utah (USA) from May 2012 through October 2013. The prehospital ECGs were applied to the algorithm and compared against activation of the CCL by an emergency department (ED) physician as the outcome of interest. In addition to calculating test characteristics, linear regression was used to look for an association between number of criteria used and accuracy, and logistic regression was used to test if any single criterion performed better than another.

RESULTS

There were 63 ECGs available for review, 39 high probability and 24 intermediate probability. The high probability STEMI tier had excellent test characteristics for ruling in STEMI when all four criteria were used, specificity 1.00 (95% CI, 0.59-1.00), positive predictive value 1.00 (0.91-1.00). Linear regression showed a strong correlation demonstrating that false-positives increased as fewer criteria were used (adjusted r-square 0.51; P <.01). Logistic regression showed no significant predictive value for any one criterion over another (P = .80). Limiting physician overread to the intermediate tier only would reduce the number of ECGs requiring physician overread by a factor of 0.62 (95% CI, 0.48-0.75; P <.01).

CONCLUSION

Prehospital STEMI ECGs can be accurately stratified to high, intermediate, and low probabilities for STEMI using the four criteria. While additional study is required, using this tiered algorithmic approach in prehospital ECGs could lead to changes in CCL activation and decreased requirements for physician overread. This may have significant clinical and quality implications.

The effects of prehospital system delays on the treatment efficacy of STEMI patients

BACKGROUND

Cardiovascular disease accounts for nearly half of all deaths in Poland. The aim of this study was to assess both the duration and the delays of prehospital treatment in ST-segment elevation myocardial infarction (STEMI) patients and how it impacts left ventricle ejection fraction (LVEF) measured at the time of discharge and the frequency of in-hospital patient mortality.

METHODS

This study retrospectively analyzed medical records from January 2011 to December 2015 (excluding the year 2013) of 573 patients who were transported to a hospital with a diagnosis of STEMI.

RESULTS

The mean time of prehospital system delays was 59 min with a maximum time of 152 min and a minimum time of 23 min. The relationship between reduced LVEF (< 55%) and in-hospital patient mortality and the relationship between length of time from first medical contact (FMC) to hospital admission was analysed in 515 respondents. Extending the time of FMC to hospital admission by 1 min increased the chances of lowering LVEF by 2% (95% CI: 1.004-1.041) and increased the chances of death by 2% (95% CI: 1.002-1.04) in STEMI patients.

CONCLUSIONS

This study emphasised how vital it is to minimise time spent with STEMI patients at the scene of their cardiovascular event by performing an ECG as quickly as possible and by immediately transporting the patient to the hospital with the targeted treatment. This may lead to the implementation of additional training in the field of ECG interpretation, increase the prevalence of teletransmission systems, and improve communication between Emergency Medical Services (EMS) and catheterization laboratories ultimately reducing patient mortality.

Multicentre analysis of current ST-elevation myocardial infarction acute care pathways

BACKGROUND

Rapid reperfusion with percutaneous coronary intervention (PCI) is vital for patients with ST segment elevation myocardial infarction (STEMI). However, the guideline-recommended time targets are regularly exceeded. The goal of this study was to gain insight into how Dutch PCI centres try to achieve these time targets by comparing their care processes with one another and with the European guideline-recommended process. In addition, accelerating factors perceived by care providers were identified.

METHODS

In this multiple case study, interviews with STEMI care providers were conducted, transcribed and used to create process descriptions per centre. Analyses consisted of within-case and between-case analyses of the processes. Accelerating factors were identified by means of open and axial coding.

RESULTS

In total, 28 interviews were conducted in six PCI centres. The centres differed from the guideline-recommended process on, for example, additional, unavoidable patient routings and monitoring delays, and from one another on the communication of diagnostic information (eg, transmitting all, only ambiguous or no ECGs) and catheterisation room preparation. These differences indicated diverging choices to maintain a balance between speed and diagnostic accuracy. Factors perceived by care providers as accelerating the process included trust in the tentative diagnosis, and avoiding unnecessary intercaregiver consultations. The combination of processes and accelerating factors were summarised in a model.

CONCLUSIONS

Numerous differences in processes between PCI centres were identified. Several time-saving strategies were applied by PCI centres, however, in different configurations. To further improve the care for patients with STEMI, best practices can be shared between centres and countries.

False Activations for ST-Segment Elevation Myocardial Infarction

First-medical-contact-to-device (FMC2D) times have improved over the past decade, as have clinical outcomes for patients presenting with ST-elevation myocardial infarction (STEMI). However, with improvements in FMC2D times, false activation of the cardiac catheterization laboratory (CCL) has become a challenging problem. The authors define false activation as any patient who does not warrant emergent coronary angiography for STEMI. In addition to clinical outcome measures for these patients, STEMI systems should collect data regarding the total number of CCL activations, the total number of emergency coronary angiograms, and the number revascularization procedures performed.

Prehospital diagnosis of patients with acute myocardial infarction

Primary percutaneous intervention (PPCI) is the preferred treatment in patients with ST elevation myocardial infarction (STEMI) if this can be performed in a timely manner. The

Chest Pain of Suspected Cardiac Origin: Current Evidence-based Recommendations for Prehospital Care

Introduction

In the United States, emergency medical services (EMS) protocols vary widely across jurisdictions. We sought to develop evidence-based recommendations for the prehospital evaluation and treatment of chest pain of suspected cardiac origin and to compare these recommendations against the current protocols used by the 33 EMS agencies in the state of California.

Methods

We performed a literature review of the current evidence in the prehospital treatment of chest pain and augmented this review with guidelines from various national and international societies to create our evidence-based recommendations. We then compared the chest pain protocols of each of the 33 EMS agencies for consistency with these recommendations. The specific protocol components that we analyzed were use of supplemental oxygen, aspirin, nitrates, opiates, 12-lead electrocardiogram (ECG), ST segment elevation myocardial infarction (STEMI) regionalization systems, prehospital fibrinolysis and β-blockers.

Results

The protocols varied widely in terms of medication and dosing choices, as well as listed contraindications to treatments. Every agency uses oxygen with 54% recommending titrated dosing. All agencies use aspirin (64% recommending 325mg, 24% recommending 162mg and 15% recommending either), as well as nitroglycerin and opiates (58% choosing morphine). Prehospital 12-Lead ECGs are used in 97% of agencies, and all but one agency has some form of regionalized care for their STEMI patients. No agency is currently employing prehospital fibrinolysis or β-blocker use.

Conclusion

Protocols for chest pain of suspected cardiac origin vary widely across California. The evidence-based recommendations that we present for the prehospital diagnosis and treatment of this condition may be useful for EMS medical directors tasked with creating and revising these protocols.

Telemetry-assisted early detection of STEMI in patients with atypical symptoms by paramedic-performed 12-lead ECG with subsequent cardiological analysis

OBJECTIVES

ECG is an essential diagnostic tool in patients with acute coronary syndrome. We aimed to determine how many patients presenting with atypical symptoms for an acute myocardial infarction show ST-segment elevations on prehospital ECG. We also aimed to study the feasibility of telemetric-assisted prehospital ECG analysis.

PATIENTS AND METHODS

Between April 2010 and February 2011, consecutive emergency patients presenting with atypical symptoms such as nausea, vomiting, atypical chest pain, palpitations, hypertension, syncope, or dizziness were included in the study. After basic measures were completed, a 12-lead ECG was written and telemetrically transmitted to the cardiac center, where it was analyzed by attending physicians. Any identification of an ST-elevation myocardial infarction resulted in patient admission at the closest coronary angiography facility.

RESULTS

A total of 313 emergency patients presented with the following symptoms: dyspnea, nausea, vomiting, dizziness/collapse, or acute hypertension. Thirty-four (11%) patients of this cohort were found to show ST-segment elevations on the 12-lead ECG. These patients were directly admitted to the closest coronary catheterization facility rather than the closest hospital. The time required for transmission and analysis of the ECG was 3.6±1.2 min.

CONCLUSION

Telemetry-assisted 12-lead ECG analysis in a prehospital setting may lead to earlier detection of ST-elevation myocardial infarction in patients with atypical symptoms. Thus, a 12-lead ECG should be considered in all prehospital patients both with typical and atypical symptoms.

The Role of EMS in Regionalized Systems of Care

The parallel advancement of prehospital and in-hospital patient care has provided impetus for the development and implementation of regionalized systems of health care for patients suffering from acute, life-threatening injury and illness. Regardless of the patient's clinical condition, regionalized systems of care revolve around the premise of providing the right care to the right patient at the right time. Current regionalization strategies have shown improvements in the time to patient treatment and in patient outcome, with the incorporation of emergency medical services (EMS) bypass as a key component of the system of care. This article discusses the emerging role of EMS as a critical component of regionalized systems essential to ensure effective and efficient use of resources to improve patient outcome. We also examine some of the benefits and barriers to implementation of regionalized systems of care and avenues for future research.

Using EMS Dispatch to Trigger STEMI Alerts Decreases Door-to-Balloon Times

Introduction

We sought to determine the potential reduction in door-to-balloon time (DTB) by allowing paramedics to perform prehospital ST-Elevation Myocardial Infarction (STEMI) notification using brief communications via emergency medical services (EMS) 9-1-1 dispatchers as soon as they saw a STEMI on 12-lead electrocardiogram (EKG). Our hypothesis was that earlier cardiac catheterization lab (CCL) activation would improve overall DTB and avoid delays arising from on-scene issues or the time required to deliver a full report.

Methods

The study setting was a single suburban community teaching hospital, which is a regional percutaneous coronary intervention (PCI) center with more than 120,000 Emergency Department (ED) visits/year and is serviced by a single tiered-response, advanced life support (ALS) paramedic-level agency. STEMI notifications from July 2009 to July 2012 occurred by either standard direct EMS-to-physician notification or by immediate 9-1-1 dispatch notification. In the 9-1-1 dispatcher-aided notification method, paramedics were asked to provide a brief one-sentence report using their lapel microphones upon immediate realization of a diagnostic EKG (usually within 1–2 minutes of patient contact). This report to the 9-1-1 dispatcher included the patient’s sex, age, and cardiologist (if known). The dispatcher then called the emergency department attending and informed them that a STEMI was being transported and that CCL activation was needed. We used retrospective chart review of a consecutive sample of patients from an existing STEMI registry to determine whether there was a statistically significant difference in DTB between the groups.

Results

Eight hundred fifty-six total STEMI alert patients arrived by EMS during the study. We excluded 730 notifications due to events such as cardiac arrest, arrhythmia, death, resolution of EKG changes and/or symptoms, cardiologist decision not to perform PCI, arrival as a transfer after prior stabilization at a referring facility or arriving by an EMS agency other than New Castle County EMS (NCC*EMS). Sixty-four (64) sequential patients from each group comprised the study sample. The average DTB (SD) for the standard communication method was 57.6 minutes (17.9), while that for dispatcher-aided communication was 46.1 minutes (12.8), (mean difference 57.6-46.1 minutes=11.5 minutes with a 95% CI [6.06,16.94]) p=0.0001. In the dispatcher-aided group, 92% of patients (59/64) met standards of ≤60 minute DTB time. Only 64% (41/64) met this goal in the standard communication group (p=0.0001).

Conclusion

Brief, early notification of STEMI by paramedics through 9-1-1 dispatchers achieves earlier CCL activation in a hospital system already using EMS-directed CCL activation. This practice significantly decreased DTB and yielded a higher percentage of patients meeting the DTB≤60 minutes quality metric.

Computerized interpretation of the prehospital electrocardiogram: predictive value for ST segment elevation myocardial infarction and impact on on-scene time

Introduction:

Computerized interpretation of the prehospital electrocardiogram (ECG) is increasingly being used in the basic life support (BLS) ambulance setting to reduce delays to treatment for patients suspected of ST segment elevation myocardial infarction (STEMI).

Objectives:

To estimate 1) predictive values of computerized prehospital 12-lead ECG interpretation for STEMI and 2) additional on-scene time for 12-lead ECG acquisition.

Methods:

Over a 2-year period, 1,247 ECGs acquired by primary care paramedics for suspected STEMI were collected. ECGs were interpreted in real time by the GEMarquette 12SL ECG analysis program. Predictive values were estimated with a bayesian latent class model incorporating the computerized ECG interpretations, consensus ECG interpretations by study cardiologists, and hospital diagnosis. On-scene time was compared for ambulance-transported patients with (n 5 985) and without (n 5 5,056) prehospital ECGs who received prehospital aspirin and/or nitroglycerin.

Results:

The computer's positive and negative predictive values for STEMI were 74.0% (95% credible interval [CrI] 69.6–75.6) and 98.1% (95% CrI 97.8–98.4), respectively. The sensitivity and specificity were 69.2% (95% CrI 59.0–78.5) and 98.9% (95% CrI 98.1–99.4), respectively. Prehospital ECGs were associated with a mean increase in on-scene time of 5.9 minutes (95% confidence interval 5.5–6.3).

Conclusions:

The predictive values of the computerized prehospital ECG interpretation appear to be adequate for diversion programs that direct patients with a positive result to hospitals with angioplasty facilities. The estimated 26.0% chance that a positive interpretation is false is likely too high for activation of a catheterization laboratory from the field. Acquiring prehospital ECGs does not substantially increase on-scene time in the BLS setting.

Difficult ECGs in STEMI: lessons learned from serial sampling of pre- and in-hospital ECGs

Prehospital interpretation of electrocardiograms (ECGs) is crucial to ensure early diagnosis and optimal treatment of patients with ST elevation myocardial infarction (STEMI). Recognition of ST-segment elevations (STE) by qualified personnel in the prehospital phase has successfully reduced the delay from the first medical contact to reperfusion. A few other ECG patterns without true STE, referred to as "STEMI equivalents", bear the same prognostic significance, reflect imminent or ongoing transmural ischemia, but are less easily identified. Hyperacute T waves, de Winter ST-T complex, Wellens' syndrome, and posterior STEMI, as well as myocardial infarction in the presence of left bundle branch block, paced rhythm or left ventricular hypertrophy, among others are diagnostic challenges. This article reviews some critical examples of ischemic ECG patterns that may be ephemeral, misinterpreted by medical staff or not identified by automated ECG algorithms, and it emphasizes the importance of serial ECG acquisition.

Ischaemic heart disease: accuracy of the prehospital diagnosis-a retrospective study

Purpose. Correct prehospital diagnosis of ischaemic heart disease (IHD) may accelerate and improve the treatment. We sought to evaluate the accuracy of prehospital diagnoses of ischemic heart diseases assigned by physicians. Methods. The Mobile Emergency Care Unit (MECU) in Odense, Denmark, services a population of 260.000. All admissions in 2009 concerning patients diagnosed in the IHD category were assessed. Outcome and diagnosis of each patient were manually validated in accordance to the final diagnosis established following admission to hospital, using the discharge summary from the relevant department as reference. Results. 428 MECU runs with a prehospital diagnosis of IHD were registered. 422 of these were included in the study and 354 of those patients were suitable for this analysis. 73,4% of the patients hospitalized with a prehospital diagnosis of IHD were initially admitted to the relevant ward. Of these patients, 40,0% had their preliminary diagnosis of IHD confirmed. 14,1% of all patients admitted to the hospital were diagnosed with nonheart conditions. Preliminary diagnoses of STEMI had an accuracy of 87,5%. Conclusions. The preliminary IHD diagnoses assigned by the MECU physicians were acceptable. In case of STEMI patients the diagnostic accuracy was excellent. In this study there was an apparent overtriage.

Ability of First-Year Paramedic Students to Identify ST-Segment Elevation Myocardial Injury on 12-Lead Electrocardiogram: A Pilot Study

Introduction:

The purpose of this study was to evaluate the ability of first-year paramedic students to identify ST-segment elevation myocardial injury (STEMI) on 12-lead electrocardiograms (ECGs) following a three-hour presentation by a board-certified emergency medicine physician experienced in ECG interpretation.

Methods:

Thirty-three first-year paramedic students with minimal to no experience in evaluating 12-lead ECGs were administered a pretest with 20 12-lead ECGs and were asked to evaluate each for: (1) presence of STEMI (STEMI identification); (2) if STEMI presents, ECG leads demonstrating ST-elevation (LEAD identification); and (3) if STEMI present, the anatomic distribution of the STEMI (ANATOMY identification). The students were randomized into two groups. Group 1 (16 students; control group) received a handout describing the evaluation of ECGs for STEMI, while Group 2 (17 students; experimental group) received the handout plus a threehour presentation on the evaluation of ECGs for STEMI. Following randomization, distribution of the STEMI handout and ECG STEMI presentation, a posttest with 20 new ECGs was administered to all participants. The pretest and posttest mean scores were compared between the two groups to determine if attendance at the presentation improved the paramedic students' abilities to evaluate and identify STEMI ECGs. Following the STEMI posttest, students in Group 1 were provided with the STEMI lecture. Students were retested with 20 new ECGs five months following the initial study to examine retention of the information taught.

Results:

The mean pre-test scores for the two groups (Group 1 vs Group 2, respectively) in STEMI identification (74.4 vs 75.6%; p = 0.79), lead identification (50.0 vs. 51.2%; p = 0.8) and anatomy identification (49.4 vs 51.8%; p = 0.60) were similar in all three categories. Post-test scores between Group 1 and Group 2 demonstrated statistically significant differences in STEMI identification (85.6 vs 92.4%; p <0.02), lead identification (73.4 vs 85.2%; p <0.02), and anatomy identification (65.9 vs 87.1%; p <0.01), with Group 2 demonstrating higher mean scores relative to Group 1 in all three categories. Comparison of mean initial pre-test and five-month retest scores for all students demonstrated statistically significant differences in STEMI identification (75.0 vs 87.4%; p <0.0001), lead identification (50.6 vs 82.2%; p <0.0001), and anatomy identification (50.6 vs 76.6%; p <0.0001).

Conclusions:

The ability of first-year paramedic students to accurately detect STEMI on prehospital 12-lead ECGs is enhanced by a structured ECG STEMI presentation provided by an emergency medicine physician, and these students maintained excellent retention of STEMI ECG skills over a five-month period.

Paramedic electrocardiogram and rhythm identification: a convenient training device

INTRODUCTION

A common reason for utilizing local paramedics and the emergency medical services is for the recognition and immediate treatment of chest pain, a complaint that has multiple possible etiologies. While many of those complaining of disease processes responsible for chest pain are benign, some will be life-threatening and will require immediate identification and treatment. The ability of paramedics to not only perform field electrocardiograms (ECGs), but to accurately diagnose various unstable cardiac rhythms has shown significant reduction in time to specific treatments. Increasing the overall accuracy of ECG interpretation by paramedics has the potential to facilitate early and appropriate treatment and decrease patient morbidity and mortality.

METHODS

A convenient training device (flip book) on ambulances and in common areas in the fire station could improve field interpretation of certain cardiac rhythms. This training device consists of illustrated sample ECG tracings and their associated diagnostic criteria. The goal was to enhance the recognition and interpretation of ECGs, and thereby, reduce delays in the initiation of treatment and potential complications associated with misinterpretation.This study was a prospective, observational study using a matched pre-test/post-test design. The study period was from November 2008 to December 2008. A total of 136 paramedics were approached to participate in this study. A pre-test consisting of 15 12-lead ECGs was given to all paramedics who agreed to participate in the study. Once the pre-tests were completed, the flip books were placed in common areas. Approximately one month after the flip books were made available to the paramedics, a post-test was administered.Statistical comparisons were made between the pre- and post-test scores for both the global test and each type of rhythm.

RESULTS

Using these data, there were no statistically significant improvements in the global ECG interpretation or on individual rhythm interpretations.

CONCLUSIONS

A flip book with multiple ECG rhythms and definitions without the benefit of any outside support was not effective in improving paramedic identification of ECG rhythms on a post-test. Suggestions for further research include repeating the study with a larger sample size; utilizing a lecturer to explain how to use the flip book in the most efficient manner; reiterating how to read and interpret ECGs; and answering questions. Comparing test scores of paramedic students, and newly certified paramedics as opposed to veteran paramedics also may indicate that the flip books are more suited for one group over another.

Cellular video-phone assisted transmission and interpretation of prehospital 12-lead electrocardiogram in acute st-segment elevation myocardial infarction

BACKGROUND

Prehospital 12-lead electrocardiogram (ECG) reduces the time to reperfusion in acute ST-segment elevation myocardial infarction (STEMI). However, the reliability of using cellular video-phone (VP) assisted interpretation of ECG is unknown.

METHODS

We studied the interphysician reliability in interpreting the ECG assisted with VP compared to print ECG interpretation. Twenty-seven physicians prospectively interpreted the ECG transmitted from the field in real-time using VP and later using the same printed ECG. The time to completion, accuracy of interpretation, and physician rating of the VP technology were recorded.

RESULTS

Similar high interphysician reliability was observed with both VP assisted and printed ECG interpretation including presence of ST-segment elevation (intraclass correlation coefficient [ICC]= 0.98 [95% CI 0.96-1] vs. 0.99 [95% CI 0.99-1]) and pathologic Q wave (ICC = 0.99 [95% CI 0.98-1] vs. 1 [95% CI 1]), respectively. The mean time to transmit and interpret the ECG with VP versus printed ECG was 3.9 ± 1.9 versus 2.1 ± 0.9 minutes, respectively, P < 0.01. On a scale of 1 to 5 with 5 being the best, the average rating of VP ease of use was 4.4 ± 0.5 and utility to recommend treatment was rated a 5.

CONCLUSION

Cellular VP-assisted transmission and interpretation in real-time of prehospital ECG has high interphysician reliability, similar to the printed ECG interpretation. Future studies testing whether VP decreases the ischemic time and expedites the reperfusion of STEMI patients are needed.

Can paramedics read ST-segment elevation myocardial infarction on prehospital 12-lead electrocardiograms?

INTRODUCTION

Activation of the cardiac catheterization laboratory prior to patient arrival at the hospital, based on a prehospital 12-lead electrocardiogram (ECG), reduces door-to-balloon time by 10-55 minutes for patients with ST-segment elevation myocardial infarction (STEMI). In emergency medical services (EMS) systems where transmission of the ECG to the emergency department (ED) is not feasible, the ability of paramedics to accurately read 12-lead ECGs is crucial to the success of a prehospital catheterization laboratory activation program. Objective. To determine whether paramedics can accurately diagnose STEMI on a prehospital 12-lead ECG and decide to activate the cardiac catheterization laboratory appropriately.

METHODS

Five chest pain scenarios were generated, with standardized prehospital ECGs accompanying each: three STEMI cases that should result in catheterization laboratory activation and two non-STEMI cases that should not. A convenience sample of paramedics in an urban/suburban EMS system examined each scenario and ECG, and indicated whether the patient had STEMI and whether they would activate the catheterization laboratory. A series of demographic and operational questions were also asked of each participant. We report diagnostic statistics, agreement (kappa), and 95% confidence intervals (CIs).

RESULTS

A convenience sample of 103 of 147 eligible paramedics (70%) was enrolled. For STEMI diagnosis, paramedics' sensitivity was 92.6% (95% CI 88.9-95.1) and specificity was 85.4% (79.7-89.8); for catheterization laboratory activation, sensitivity was 88.0% (83.8-91.3) and specificity was 88.3% (83.0-92.2). False-positive activation of the catheterization laboratory occurred in 8.1% (5.4-12.0) of cases. Of the STEMI cases, 94.1% were correctly read as STEMI, and 91.0% had the catheterization laboratory appropriately activated. Of the non-STEMI cases, 14.9% were incorrectly read as STEMI, and 12.0% had the catheterization laboratory inappropriately activated. The paramedics' comfort with calling a "chest pain alert" with no resulting catheterization laboratory activation (the current practice in this system) was not statistically different from their comfort with calling a chest pain alert if that call were to automatically result in catheterization laboratory activation (p > 0.05).

CONCLUSIONS

Paramedics in an urban/suburban EMS system can diagnose STEMI and identify appropriate cardiac catheterization laboratory activations with a high degree of accuracy, and an acceptable false-positive rate, when tested using paper-based scenarios.

Frequency of non-ST-segment elevation injury patterns on prehospital electrocardiograms

INTRODUCTION

Prehospital electrocardiograms (ECGs) have been recommended to facilitate early diagnosis of ST-segment elevation myocardial infarction (STEMI). However, prehospital ECGs can also be used to triage patients with non-ST-segment elevation acute coronary syndromes, who comprise a majority of patients with ischemic events presenting by ambulance to overcrowded emergency departments.

OBJECTIVE

We assessed the frequency of non-ST-segment elevation injury patterns on prehospital ECGs in patients with a chief complaint of chest pain evaluated by the emergency medical services (EMS) system.

METHODS

We analyzed prehospital ECGs of patients with the chief complaint of chest pain during a nine-month period. The ECGs were divided into three categories: injury pattern; no injury pattern; and technically uninterpretable. Injury pattern criteria were as follows: 1) regional ST depression >or=1.0 mm; 2) regional T-wave inversion (TWI) >or=3 mm; 3) left bundle branch block (LBBB); and 4) regional ST-segment elevation >or=1.0 mm. Descriptive statistics with 95% confidence intervals (CIs) are presented.

RESULTS

Prehospital ECGs were obtained for 322 of 340 chest pain patients: 72% were men; the average age was 60 years (range 18-96 years). Seventy-seven ECGs (24%, 95% CI 19.3-28.9%) met the criteria for injury pattern, 230 (71%) did not show injury, and 15 (5%) were uninterpretable. Of the 77 ECGs that exhibited an injury pattern, 39 (51%) showed ST depression, seven (9%) TWI, seven (9%) LBBB, and 24 (31%) ST-segment elevation. Thus, non-ST-segment elevation injury patterns (ST depression/TWI/LBBB) accounted for 53 (17%, 95% CI 12.6-20.9) of the total 322 prehospital ECGs.

CONCLUSION

Our findings demonstrate a relatively high frequency (17%) of non-ST-segment elevation injury patterns on prehospital ECGs of patients who summon EMS because of chest pain. These results suggest the potential of prehospital ECGs to facilitate early triage in these high-risk chest pain patients who present to overcrowded emergency departments.

The Positive Predictive Value of Paramedic Versus Emergency Physician Interpretation of the Prehospital 12-Lead Electrocardiogram

BACKGROUND

Obtaining a prehospital 12-lead ECG may improve triage and expedite care of patients with acute myocardial infarction (AMI). Whether the ECG should undergo physician review prior to activation of a percutaneous intervention (PCI) team is unclear.

OBJECTIVE

To document the positive predictive value (PPV) of the prehospital 12-lead ECG when interpreted by paramedics versus emergency physicians.

METHODS

This was a prospective, observational study. In November 2003, our local health care and emergency medical services (EMS) systems implemented a prehospital "cardiac alert" program in which patients suspected of having ST-elevation myocardial infarction (STEMI) based on the prehospital 12-lead ECG were diverted away from receiving facilities without emergent PCI capability and the PCI team was mobilized. For the first year, a cardiac alert was activated by paramedics (Phase I). After the first year, the ECG was transmitted to the ED, with the emergency physician (EP) responsible for activation (Phase II). The PPV for cardiac alerts in Phases I and II were compared by using three different "gold standards": cardiologist interpretation of the prehospital 12-lead ECG, disposition to emergent PCI, and coronary lesions on angiography or arrest prior to emergent PCI.

RESULTS

A total of 110 patients were enrolled (54 in Phase I, 56 in Phase II). Cardiologist confirmation of a STEMI on the prehospital 12-lead EKG was 42/54 (78%) in Phase I and 54/56 (96%) in Phase II. Disposition to emergent PCI occurred in 38/54 (70%) Phase I patients and 51/56 (91%) Phase II patients. Lesions at catheterization or arrest prior to emergent PCI were observed in 41/54 (69%) of Phase I patients and 50/56 (89%) of Phase II patients. All of these comparisons achieved statistical significance (p < 0.01).

CONCLUSIONS

Transmission to the ED for EP interpretation improves the PPV of the prehospital 12-lead ECG for triage and therapeutic decision-making.

A Bayesian sensitivity analysis of out-of-hospital 12-lead electrocardiograms: implications for regionalization of cardiac care

BACKGROUND

The effectiveness of out-of-hospital regionalization of ST-elevation myocardial infarction (STEMI) patients to hospitals providing primary percutaneous coronary intervention depends on the accuracy of the out-of-hospital 12-lead electrocardiogram (PHTL). Although estimates of sensitivity and specificity of PHTL for STEMI have been reported, the impact of out-of-hospital STEMI prevalence on positive predictive value (PPV) has not been evaluated.

OBJECTIVES

To describe the relationship between varying population STEMI prevalences and PHTL predictive values, using ranges of PHTL sensitivity and specificity.

METHODS

The authors performed a Bayesian analysis using PHTL, where values for sensitivities (60%-70%), specificities (98%), and two prevalence ranges (0.5%-5% and 5%-20%) were derived from a literature review. PPV prediction intervals were compared with three months of prospective data from the Los Angeles County Emergency Medical Services Agency STEMI regionalization program.

RESULTS

When the estimated prevalence of STEMI in the out-of-hospital population is 5%-20%, the median PPV of the PHTL is 83% (95% credible interval [CrI] = 53% to 97%). However, if the population prevalence of STEMI is between 0.5% and 5%, the median PPV is 43% (95% CrI = 12% to 86%). When the PPV prediction intervals were incorporated with the Los Angeles County Emergency Medical Services Agency data, the PPV was 66%.

CONCLUSIONS

Even when assuming high specificity for PHTL, the false-positive rate will be considerable if applied to a population at low risk for STEMI. Before broadening application of PHTL to low-risk patients, the implications of a high false-positive rate should be considered.

Use of the prehospital ECG improves door-to-balloon times in ST segment elevation myocardial infarction irrespective of time of day or day of week

BACKGROUND

The use of the prehospital electrocardiogram (ECG) to identify patients with ST-segment elevation myocardial infarction (STEMI), coupled with a centralised system to alert the cardiac catheterisation team in preparation for prompt intervention, has been shown to reduce door-to-balloon times (DBT) effectively. A confounding variable in prolonging the recommended 90 min DBT is the time of day or day of the week of patient presentation. We postulated that use of the prehospital ECG, coupled with an emergency department initiated "Cath Alert" system, could neutralise DBT delays related to time of day or day of week.

METHODS

A prospective study was conducted on 167 consecutive patients presenting to our emergency department with acute STEMI. All patients were treated with primary percutaneous coronary intervention. Patients were grouped according to time of presentation: during regular hours (Monday to Friday 08:00 to 17:00) vs off hours (after 17:00 on weekdays and all hours on weekends). Baseline recorded variables included mode of presentation, transmission of prehospital ECG, and activation of Cath Alert system.

RESULTS

Overall, the mean (SD) DBT was 69 (35) mins, with the majority of patients (n = 131, 78%) achieving the recommended DBT of 90 mins. The shortest DBT occurred in patients who arrived by emergency medical services with use of the prehospital ECG and Cath Alert system (53 (21) min), while those who arrived as a walk-in without use of emergency medical services had the longest DBT (105 (38) min; p<0.001). Compared to regular hours, presentation during off hours prolonged DBT in patients presenting via emergency medical services (75 (16) vs 53 (18) min, p = 0.03). With transmission of the prehospital ECG, the delay in DBT was improved among those presenting off hours, nullifying the adverse effect of off hour presentation (54 (21) vs 49 (22) min; p = 0.26).

CONCLUSION

Variables such as time of day and mode of presentation have an impact on achieving currently recommended DBT in patients with STEMI. With the addition of each prehospital variable in succession-that is, arrival by emergency medical services, Cath Alert system, and the prehospital ECG-the DBT can be progressively shortened and the adverse "off hour effect" nullified.

Prehospital electrocardiogram and early helicopter dispatch to expedite interfacility transfer for percutaneous coronary intervention

Care provision and benchmarking for patients with ST-elevation myocardial infarction (STEMI) have focused on streamlining time between initial hospital presentation and opening of theinfarct-related artery. In a Boston-area regional system already characterized by expedited advanced life support (ALS) dispatch and paramedic performance of prehospital electrocardiogram (EKG), a critical pathway was designed that allows for helicopter dispatch based on ground ALS providers' STEMI diagnosis. The pathway dictates that as soon as ALS crews make the diagnosis of STEMI from their 12-lead EKG, they will contact Boston MedFlight (BMF) and a helicopter will be immediately dispatched to the participating community hospital (Lawrence General Hospital [LGH]). Based on historical and predicted time patterns, it is expected that BMF will arrive at LGH soon after the ALS ambulance delivers the patient to the LGH emergency department (ED). The patient will then undergo BMF transport from the ED into central Boston with direct transfer into an awaiting cardiac catheterization suite (ie, bypassing the receiving hospital ED). The pathway minimizes the delay between patient arrival at LGH and BMF arrival for transport to the catheterization laboratory. It is hoped that implementation of the critical pathway will allow the region's patients with STEMI to achieve coronary arterial patency within 90 minutes of LGH presentation. If the pathway proves effective, it can serve as a model for other regions and programs with similar clinical and logistic situations and advance the concept of "diagnosis-to-balloon" time.