Pre-hospital 12-lead electrocardiography programs: a call for implementation by emergency medical services systems providing advanced life support--National Heart Attack Alert Program (NHAAP) Coordinating Committee; National Heart, Lung, and Blood Institute (NHLBI); National Institutes of Health

Feasibility of patch-type wireless 12-lead electrocardiogram in laypersons

Various efforts have been made to diagnose acute cardiovascular diseases (CVDs) early in patients. However, the sole option currently is symptom education. It may be possible for the patient to obtain an early 12-lead electrocardiogram (ECG) before the first medical contact (FMC), which could decrease the physical contact between patients and medical staff. Thus, we aimed to verify whether laypersons can obtain a 12-lead ECG in an off-site setting for clinical treatment and diagnosis using a patch-type wireless 12-lead ECG (PWECG). Participants who were ≥ 19 years old and under outpatient cardiology treatment were enrolled in this simulation-based one-arm interventional study. We confirmed that participants, regardless of age and education level, can use the PWECG on their own. The median age of the participants was 59 years (interquartile range [IQR] = 56-62 years), and the median duration to obtain a 12-lead ECG result was 179 s (IQR = 148-221 s). With appropriate education and guidance, it is possible for a layperson to obtain a 12-lead ECG, minimizing the contact with a healthcare provider. These results can be used subsequently for treatment.

Accuracy of ECG chest electrode placements by paramedics: an observational study

Background:

The use of the 12-lead electrocardiogram (ECG) is common in sophisticated pre-hospital emergency medical services but its value depends upon accurate placement of the ECG electrodes. Several studies have shown widespread variation in the placement of chest electrodes by other health professionals but no studies have addressed the accuracy of paramedics. The main objective of this study was to ascertain the accuracy of the chest lead placements by registered paramedics.

Methods:

Registered paramedics who attended the Emergency Services Show in Birmingham in September 2018 were invited to participate in this observational study. Participants were asked to place the chest electrodes on a male model in accordance with their current practice. Correct positioning was determined against the Society for Cardiological Science and Technology’s 2017 clinical guidelines for recording a standard 12-lead ECG, with a tolerance of 19 mm being deemed acceptable based upon previous studies.

Results:

Fifty-two eligible participants completed the study. Measurement of electrode placement in the vertical and horizontal planes showed a high level of inaccuracy, with 3/52 (5.8%) participants able to accurately place all chest electrodes. In leads V₁–V₃, the majority of incorrect placements were related to vertical displacement, with most participants able to identify the correct horizontal position. In V₄, the tendency was to place the electrode too low and to the left of the pre-determined position, while V₅ tended to be below the expected positioning but in the correct horizontal alignment. There was a less defined pattern of error in V₆, although vertical displacement was more likely than horizontal displacement.

Conclusions:

Our study identified a high level of variation in the placement of chest ECG electrodes, which could alter the morphology of the ECG. Correct placement of V₁ improved placement of other electrodes. Improved initial and refresher training should focus on identification of landmarks and correct placement of V₁.

Twelve-Lead Electrocardiogram Acquisition With a Patchy-Type Wireless Device in Ambulance Transport: Simulation-Based Randomized Controlled Trial

Background

Cardiovascular disease is the leading cause of death worldwide. Early recognition, diagnosis, and reperfusion are the key elements of treatment for ST-segment elevation myocardial infarction. The absence of a prehospital 12-lead electrocardiogram (P12ECG) can cause definitive treatment delay and repeated transfer. Although guidelines highly recommend the measurement and transmission of P12ECG data, P12ECG use has not been widely established.

Objective

The aim of this study was to verify the time-efficiency and feasibility of the use of a patchy-type 12-lead ECG measuring and transmitting device (P-ECG) by an emergency medical technician (EMT) in an ambulance during patient transport.

Methods

This was a simulation-based prospective randomized crossover-controlled study that included EMTs. The participants were randomly assigned to one of two groups. Group A began the experiment with a conventional 12-lead ECG (C-ECG) device and then switched to the intervention device (P-ECG), whereas group B began the experiment with the P-ECG and then switched to the C-ECG. All simulations were performed inside an ambulance driving at 30 km/h. The time interval was measured from the beginning of ECG application to completion of sending the results. After the simulation, participants were administered the System Usability Scale questionnaire about usability of the P-ECG.

Results

A total of 18 EMTs were recruited for this study with a median age of 35 years. The overall interval time for the C-ECG was 254 seconds (IQR 247-270), whereas the overall interval time for the P-ECG was 130 seconds (IQR 112-150), with a significant difference (P<.001). Significant differences between the C-ECG and P-ECG were identified at all time intervals, in which the P-ECG device was significantly faster in all intervals, except for the preparation interval in which the C-ECG was faster (P=.03).

Conclusions

Performance of 12-lead ECG examination and transmission of the results using P-ECG are faster than those of C-ECG during ambulance transport. With the additional time afforded, EMTs can provide more care to patients and transport patients more rapidly, which may help reduce the symptoms-to-balloon time for patients with acute coronary syndrome.

Trial Registration

ClinicalTrials.gov NCT04114760; https://www.clinicaltrials.gov/ct2/show/NCT04114760

Electrocardiogram Interpretation Competency Among Paramedic Students

BACKGROUND

Electrocardiography is an essential emergency tool used in the pre-hospital setting. However, no studies have yet assessed electrocardiogram (ECG) interpretation among emergency medical services (EMS) students in Saudi Arabia. This study aimed to determine the ECG interpretation competency of paramedic students.

METHODOLOGY

Cross-sectional, single-center study, a pre-validated, self-administered, two-part questionnaire first created by Coll-Badell et al was used to assess the ECG interpretation competency of paramedic students at Prince Sultan College for Emergency Medical Services (PSCEMS) in King Saud University. Participant data were collected and analyzed to identify factors associated with improved competency.

RESULTS

All students of PSCEMS were included, and 137 of 248 paramedic students completed the questionnaire (55% response rate); 88 students (64.2%) scored >7.5 points, indicating competency in (ECG) interpretation. Factors such as grade point average (GPA) (>3.5) and enrollment in cardiology and advanced cardiac life support courses were found to be significantly associated with competency (p<0.001).

CONCLUSION

The majority of paramedic students were found to be competent in ECG interpretation. GPA and enrollment in cardiology and advanced cardiac life support courses were significantly associated with improved competency.

A Dynamic Systems Approach for Detecting and Localizing of Infarct-Related Artery in Acute Myocardial Infarction Using Compressed Paper-Based Electrocardiogram (ECG)

Timely evaluation and reperfusion have improved the myocardial salvage and the subsequent recovery rate of the patients hospitalized with acute myocardial infarction (MI). Long waiting time and time-consuming procedures of in-hospital diagnostic testing severely affect the timeliness. We present a Poincare pattern ensemble-based method with the consideration of multi-correlated non-stationary stochastic system dynamics to localize the infarct-related artery (IRA) in acute MI by fully harnessing information from paper-based Electrocardiogram (ECG). The vectorcardiogram (VCG) diagnostic features extracted from only 2.5-s long paper ECG recordings were used to hierarchically localize the IRA-not mere localization of the infarcted cardiac tissues-in acute MI. Paper ECG records and angiograms of 106 acute MI patients collected at the Heart Artery and Vein Center at Fresno California and the 12-lead ECG signals from the Physionet PTB online database were employed to validate the proposed approach. We reported the overall accuracies of 97.41% for healthy control (HC) vs. MI, 89.41 ± 9.89 for left and right culprit arteries vs. others, 88.2 ± 11.6 for left main arteries vs. right-coronary-ascending (RCA) and 93.67 ± 4.89 for left-anterior-descending (LAD) vs. left-circumflex (LCX). The IRA localization from paper ECG can be used to timely triage the patients with acute coronary syndromes to the percutaneous coronary intervention facilities.

Reducing Delay to Treatment of ST-Elevation Myocardial Infarction With Software Electrocardiographic Interpretation and Transmission (SCINET)

BACKGROUND

Prehospital diagnosis of ST-elevation myocardial infarction (STEMI) has resulted in improved outcomes. However, many patients still walk in to the emergency department (ED) with STEMI, experiencing delays and worse outcomes. Software electrocardiogram (ECG) diagnosis of STEMI and electronic transmission to a cardiologist may result in improved door-to-device (D2D) times.

METHODS

We retrospectively identified all patients presenting with STEMI from January 2015 to September 2016. Components of delay in D2D, ED variables, and the patients' ECGs were extracted from our regional database. All ECGs performed for suspected myocardial infarction in the region were extracted over the study period. We assessed the accuracy of the software 12SL in diagnosing STEMI, ED contributors to delays in D2D, and the potential reduction in D2D if software diagnosis of STEMI resulted in activation of the cardiac catheterization laboratory.

RESULTS

A total of 379 patients presented to an ED in our region and received primary percutaneous coronary intervention over the study period. In the 143,574 ECGs performed over the study period for suspected STEMI, the overall sensitivity and specificity of 12SL were 90.5% and 99.98%, respectively. We estimated a potential 17-minute reduction in D2D in the 90.5% of patients correctly identified as having STEMI, with a false activation rate of 4%. Female patients and older patients experienced an even larger potential benefit, with 24- and 25-minute reductions in D2D, respectively.

CONCLUSIONS

Patients who walk in to an ED with STEMI experience significant system-related delays in recognition and treatment. Automated software diagnosis of STEMI is accurate and could result in significant improvements in D2D times.

Emergency Medical Services Utilization and Outcomes of Patients with ST-Elevation Myocardial Infarction in Lebanon

BACKGROUND

Arrival of patients with ST-elevation myocardial infarction (STEMI) by Emergency Medical Services (EMS) results in shorter reperfusion times and lower mortality in developed countries.

OBJECTIVES

This study examines EMS use by STEMI patients in Lebanon and associated clinical outcomes.

METHODS

A retrospective observational study with chart review was carried out for STEMI patients arriving to the Emergency Department of a tertiary care center in Lebanon between January 1, 2013 and August 31, 2016. A descriptive analysis was done and followed by a bivariate analysis comparing two groups of patients (EMS vs. Non-EMS).

RESULTS

A total of 280 patients were included in the study. They were mostly male (71.8%). Mean age was 65.1 years (95% confidence interval [CI] 63.4-66.9). Only 12.5% (95% CI 8.6-16.4) presented by EMS. Chest pain (81.1%) was the most common presenting symptom. Anterior myocardial infarction was the most common electrocardiogram (ECG) diagnosis (51.4%). Most patients were admitted (98.2%), and 72.0% of these patients were treated with primary percutaneous coronary intervention. Cardiogenic shock was the most frequent in-hospital complication (6.2%). The mortality rate was 7.1%. Mean door-to-ECG and door-to-balloon times were 10.8 (95% CI 7.1-14.4) min and 106.2 (95% CI 95.9-116.6) min, respectively. Patients' characteristics, presenting symptoms, outcomes, and performance metrics were similar between the two groups.

CONCLUSION

EMS is underutilized by STEMI patients in Lebanon and is not associated with improvement in clinical outcomes. Medical oversight and quality initiatives focusing on outcomes of patients with timely sensitive emergencies are needed to advance the prehospital care system in Lebanon.

A model for predicting emergency physician opinion of electrocardiogram tracing data quality

BACKGROUND

Limited work has established an objective measure of ECG quality that correlates with physician opinion of the study. We seek to establish a threshold of acceptable ECG data quality for the purpose of ruling out STEMI derived from emergency physician opinion.

METHODS

A panel of three emergency physicians rated 240 12-Lead ECGs as being acceptable or unacceptable data quality. Each lead of the ECG had the following measurements recorded: baseline wander, QRS signal amplitude, and artifact amplitude. A lasso regression technique was used to create the model.

RESULTS

The area under the curve for the model using all 36 elements is 1.0, indicating a perfect fit. A simplified model using 22 terms has an area under the curve of 0.994.

CONCLUSIONS

This study demonstrated that emergency physician opinion of ECG quality for the purpose of ruling out STEMI can be predicted through a regression model.

Pre-hospital detection of acute ischemic stroke secondary to emergent large vessel occlusion: lessons learned from electrocardiogram and acute myocardial infarction

Currently, there is no device capable of detecting acute ischemic stroke (AIS) secondary to emergent large vessel occlusion (ELVO) in the pre-hospital setting. The inability to reliably identify patients that would benefit from primary treatment with endovascular thrombectomy remains an important limitation to optimizing emergency medical services (EMS) triage models and time-to-treatment. Several clinical grading scales that rely solely on clinical examination have been proposed and have demonstrated only moderate predictive ability for ELVO. Consequently, a technology capable of detecting ELVO in the pre-hospital setting would be of great benefit. An analogous scenario existed decades ago, in which pre-hospital detection of acute myocardial infarction (AMI) was unreliable until the emergence of the 12-lead ECG and its adoption by EMS providers. This review details the implementation of pre-hospital ECG (PHECG) for the detection of AMI and explores how early experience with PHECG may be applied to ELVO detection devices, once they become available.

Contemporary management of ST-segment elevation myocardial infarction

ST-elevation myocardial infarction (STEMI), which constitutes nearly 25-40 % of current acute myocardial infarction (AMI) cases, is a medical emergency that requires prompt recognition and treatment. Since the 2013 STEMI practice guidelines, a wealth of additional data that may further advance optimal STEMI practices has emerged. These data highlight the importance of improving patient treatment and transport algorithms for STEMI from non-primary percutaneous coronary intervention (PCI) centers. In addition, a focus on the reduction of total pain-to-balloon (P2B) times rather than simply door-to-balloon (D2B) times may further improve outcomes after primary PCI for STEMI. The early administration of newer oral P2Y12 inhibitors, including crushed forms of these agents for faster absorption, represents another treatment advancement. Recent data also suggest avoiding concurrent morphine use due to interactions with P2Y12 inhibitors. Furthermore, new technological advancements and investigational therapies, including Bioresorbable Vascular Scaffolds and the use of pre-intervention intravenous microbubbles with transthoracic ultrasound, hold promise to play a useful role in future STEMI care. Despite these advancements, the prompt recognition of STEMI, at both the patient and health care system level, remains the cornerstone of optimal treatment.

Comparison of primary percutaneous coronary intervention in patients with ST-elevation myocardial infarction during and prior to availability of an in-house STEMI system: early experience and intermediate outcomes of the HARRT program for achieving routine D2B times <60 minutes

BACKGROUND

Over the last decade, significant advances in ST-elevation myocardial infarction (STEMI) workflow have resulted in most hospitals reporting door-to-balloon (D2B) times within the 90 min standard. Few programs have been enacted to systematically attempt to achieve routine D2B within 60 min. We sought to determine whether 24-hr in-house catheterization laboratory coverage via an In-House Interventional Team Program (IHIT) could achieve D2B times below 60 min for STEMI and to compare the results to the standard primary percutaneous coronary intervention (PCI) approach.

METHODS

An IHIT program was established consisting of an attending interventional cardiologist, and a catheterization laboratory team present in-hospital 24 hr/day. For all consecutive STEMI patients, we compared the standard primary PCI approach during the two years prior to the program (group A) to the initial 20 months of the IHIT program (group B), and repeated this analysis for only CMS-reportable patients. The D2B process was analyzed by calculating workflow intervals. The primary endpoint was D2B process times, and secondary endpoints included in-hospital and 6-month cardiovascular outcomes and resource utilization.

RESULTS

An IHIT program for STEMI resulted in significant reductions across all treatment intervals with an overall 57% reduction in D2B time, and an absolute reduction in mean D2B time of 71 min. There were no differences pre- and post-program implementation in regard to individual or composite components of in-hospital cardiovascular outcomes; however at 6 months, there was a reduction in cardiovascular rehospitalization after program implementation (30 vs. 5%, P < 0.01). The IHIT program resulted in a significant reduction in length-of-stay (LOS) (90 ± 102 vs. 197 ± 303 hr, P = 0.02), and critical care time (54 ± 97 vs. 149 ± 299 hr, P = 0.02).

CONCLUSIONS

Availability of an in-house 24-hr STEMI team significantly decreased reperfusion time and led to improved clinical outcomes and a shorter LOS for PCI-treated STEMI patients.

The availability of prior ECGs improves paramedic accuracy in recognizing ST-segment elevation myocardial infarction

INTRODUCTION

Early and accurate identification of ST-elevation myocardial infarction (STEMI) by prehospital providers has been shown to significantly improve door to balloon times and improve patient outcomes. Previous studies have shown that paramedic accuracy in reading 12 lead ECGs can range from 86% to 94%. However, recent studies have demonstrated that accuracy diminishes for the more uncommon STEMI presentations (e.g. lateral). Unlike hospital physicians, paramedics rarely have the ability to review previous ECGs for comparison. Whether or not a prior ECG can improve paramedic accuracy is not known.

STUDY HYPOTHESIS

The availability of prior ECGs improves paramedic accuracy in ECG interpretation.

METHODS

130 paramedics were given a single clinical scenario. Then they were randomly assigned 12 computerized prehospital ECGs, 6 with and 6 without an accompanying prior ECG. All ECGs were obtained from a local STEMI registry. For each ECG paramedics were asked to determine whether or not there was a STEMI and to rate their confidence in their interpretation. To determine if the old ECGs improved accuracy we used a mixed effects logistic regression model to calculate p-values between the control and intervention.

RESULTS

The addition of a previous ECG improved the accuracy of identifying STEMIs from 75.5% to 80.5% (p=0.015). A previous ECG also increased paramedic confidence in their interpretation (p=0.011).

CONCLUSIONS

The availability of previous ECGs improves paramedic accuracy and enhances their confidence in interpreting STEMIs. Further studies are needed to evaluate this impact in a clinical setting.

Effects of prehospital 12-lead ECG on processes of care and mortality in acute coronary syndrome: a linked cohort study from the Myocardial Ischaemia National Audit Project

OBJECTIVE

To describe patterns of prehospital ECG (PHECG) use and determine its association with processes and outcomes of care in patients with ST-elevation myocardial infarction (STEMI) and non-STEMI.

METHODS

Population-based linked cohort study of a national myocardial infarction registry.

RESULTS

288 990 patients were admitted to hospitals via emergency medical services (EMS) between 1 January 2005 and 31 December 2009. PHECG use increased overall (51% vs 64%, adjusted OR (aOR) 2.17, 95% CI 2.12 to 2.22), and in STEMI (64% vs 79%, aOR 2.34, 95% CI 2.25 to 2.44). Patients who received PHECG were younger (71 years vs 74 years, P<0.0001); and less likely to be female (33.1% vs 40.3%, OR 0.87, 95% CI 0.86 to 0.89), or to have comorbidities than those who did not. For STEMI, reperfusion was more frequent in those having PHECG (83.5% vs 74.4%, p<0.0001). PHECG was associated with more primary percutaneous coronary intervention patients achieving call-to-balloon time <90 min (27.9% vs 21.4%, aOR 1.38, 95% CI 1.24 to 1.54) and more patients who received fibrinolytic therapy achieving door-to-needle time <30 min (90.6% vs 83.7%, aOR 2.13, 95% CI 1.91 to 2.38). Patients with PHECG exhibited significantly lower 30-day mortality rates than those who did not (7.4% vs 8.2%, aOR 0.94, 95% CI 0.91 to 0.96).

CONCLUSIONS

Findings from this national MI registry demonstrate a survival advantage in STEMI and non-STEMI patients when PHECG was used.

Prehospital telemedicine electrocardiogram triage for a regional public emergency medical service: is it worth it? A preliminary cost analysis

BACKGROUND

Telemedicine has been shown to improve quality of health-care delivery in several fields of medicine; its cost-effectiveness, however, is still a matter of debate.

HYPOTHESIS

Pre-hospital telemedicine electrocardiogram triage for regional public emergency medical service may reduce costs.

METHODS

An economic evaluation (cost analysis) was performed from the perspective of regional health-care system. Patients enrolled in the study and considered for cost analysis were those who called the local emergency medical service (EMS; dialing 1-1-8) during 2012 and underwent prehospital field triage with a telemedicine electrocardiogram (ECG) in the case of suspected acute cardiac disease (acute coronary syndrome, arrhythmia). The prehospital ECGs were read by a remote cardiologist, available 24/7. Cost savings associated with this method were calculated by subtracting the cost of prehospital triage with telemedicine support from the cost of conventional emergency department triage (ECG and consultation by a cardiologist).

RESULTS

During 2012, the regional EMS performed 109 750 ECGs by telemedicine support. The associated total cost for the regional health-care system was €1 833 333, with a €16.70 cost per single ECG/consultation. Given the cost of similar conventional emergency department treatment from a regional rate list of €24.80 to €55.20, the savings was €8.10 to €38.40 per ECG/consultation (total savings, €891 759.50 to €4 219 379.50). The cost for ruling out an acute cardiac disease was €25.30; for a prehospital diagnosis of cardiovascular disease, €49.20. With 629 prehospital diagnoses of ST-elevation myocardial infarction and reported reductions in mortality thanks to prehospital diagnosis deduced from prior studies, 69 lives per year presumably could be saved, with a cost per quality-adjusted life year gained of €1927, €990/€ - 2508 after correction for potential savings.

CONCLUSIONS

Prehospital EMS triage with telemedicine ECG in patients with suspected acute cardiac disease may reduce health-care costs.

Factors associated with longer time to treatment for patients with suspected acute coronary syndromes: a cohort study

BACKGROUND

Rapid treatment of acute coronary syndromes (ACS) is important; causes of delay in emergency medical services care of ACS are poorly understood.

METHODS AND RESULTS

We performed an analysis of data from IMMEDIATE (Immediate Myocardial Metabolic Enhancement during Initial Assessment and Treatment in Emergency Care), a randomized controlled trial of emergency medical services treatment of people with symptoms suggesting ACS, using hierarchical multiple regression of elapsed time. Out-of-hospital ECGs were performed on 54,230 adults calling 9-1-1; 871 had presumed ACS, 303 of whom had ST-segment elevation myocardial infarction and underwent percutaneous coronary intervention. Women, participants with diabetes mellitus, and participants without previous cardiovascular disease waited longer to call 9-1-1 (by 28 minutes, P<0.01; 10 minutes, P=0.03; and 6 minutes, P=0.02, respectively), compared with their counterparts. Time from emergency medical services arrival to ECG was longer for women (1.5 minutes; P<0.01), older individuals (1.3 minutes; P<0.01), and those without a primary complaint of chest pain (3.5 minutes; P<0.01). On-scene times were longer for women (2 minutes; P<0.01) and older individuals (2 minutes; P<0.01). Older individuals and participants presenting on weekends and nights had longer door-to-balloon times (by 10, 14, and 11 minutes, respectively; P<0.01). Women and older individuals had longer total times (medical contact to balloon inflation: 16 minutes, P=0.01, and 9 minutes, P<0.01, respectively; symptom onset to balloon inflation: 31.5 minutes for women; P=0.02).

CONCLUSIONS

We found delays throughout ACS care, resulting in substantial differences in total times for women and older individuals. These delays may impact outcomes; a comprehensive approach to reduce delay is needed.

Variation in the use of 12-lead electrocardiography for patients with chest pain by emergency medical services in North Carolina

Background

Prehospital 12‐lead electrocardiography (ECG) is critical to timely STEMI care although its use remains inconsistent. Previous studies to identify reasons for failure to obtain a prehospital ECG have generally only focused on individual emergency medical service (EMS) systems in urban areas. Our study objective was to identify patient, geographic, and EMS agency‐related factors associated with failure to perform a prehospital ECG across a statewide geography.

Methods and Results

We analyzed data from the Prehospital Medical Information System (PreMIS) in North Carolina from January 2008 to November 2010 for patients >30 years of age who used EMS and had a prehospital chief complaint of chest pain. Among 3.1 million EMS encounters, 134 350 patients met study criteria. From 2008–2010, 82 311 (61%) persons with chest pain received a prehospital ECG; utilization increased from 55% in 2008 to 65% in 2010 (trend P<0.001). Utilization by health referral region ranged from 22.9% to 74.2% and was lowest in rural areas. Men were more likely than women to have an ECG performed (63.0% vs 61.3%, adjusted RR 1.02, 95% CI 1.01 to 1.04). The certification‐level of the EMS provider (paramedic vsbasic/intermediate) and system‐level ECG equipment availability were the strongest predictors of ECG utilization. Persons in an ambulance with a certified paramedic were significantly more likely to receive a prehospital ECG than nonparamedics (RR 2.15, 95% CI 1.55, 2.99).

Conclusions

Across a large geographic area prehospital ECG use increased significantly, although important quality improvement opportunities remain. Increasing ECG availability and improving EMS certification and training levels are needed to improve overall care and reduce rural‐urban treatment differences.

The Critical Imperative: Prehospital Management of the Patient with ST-Elevation Myocardial Infarction

Prehospital care is critical to achieve the goal of timely reperfusion in patients with ST-elevation myocardial infarction. Prehospital care is delivered by emergency medical services (EMS) personnel, which include emergency medical dispatchers, first responders, and ambulance response. There is considerable variation in the training and capabilities of the EMS providers in the United States depending on the location (ie, rural vs urban) and local jurisdictions. In this article, the key components of prehospital care of the patient with ST-elevation myocardial infarction and the various levels of training and capabilities of EMS providers are discussed.

Achievement of a median door-to-balloon time of less than 90 minutes by implementation of organizational changes in the 'Emergency Department to Cath Lab' pathway: a 5-year analysis

RATIONALE

At present, most patients presenting directly to emergency departments (EDs) do not meet the recommended door-to-balloon goal of less than 90 minutes for ST-elevation myocardial infarction (STEMI) patients. Until the year 2005, the goal of less than 90 minutes door-to-balloon time has been rarely achieved in our hospital (i.e. 17% of all cases).

METHOD

Some organizational changes - including immediate involvement of the cardiologist in ED - were established to improve our performance. To evaluate the results of these changes, we have measured the intervals pain-to-door, door-to-electrocardiogram (ECG) and ECG-to-balloon for all the consecutive STEMI patients (n = 206) observed in our hospital during three sample months (May to July) of the years 2005 to 2009. We have then calculated the times door-to-balloon and pain-to-balloon (total ischemic time).

RESULTS

We have demonstrated that the door-to-balloon time has been progressively reduced to less than 90 minutes in 73% of patients. Only 4.5% of all patients still have a door-to-balloon time greater than 150 minutes (17% in 2005). It is also notable the 60% reduction (from 330 to 140 minutes) of the pain-to-door time, the so-called 'out of hospital avoidable delay', was achieved by a sensitization campaign directed to the whole population of the province.

CONCLUSION

Taken together, all these organizational changes have allowed to reduce the total ischemic time from 465 minutes in year 2005 to 232 minutes in year 2009, thereby demonstrating the effectiveness of our intervention.

ST elevation: telling pathology from the benign patterns

Benefits of early reperfusion in patients presenting with acute ST elevation myocardial infarction (STEMI) are well known. The American College of Cardiology / American Heart Association guidelines recommend triage decisions are made within 10 minutes of performing initial electrocardiogram (ECG). Since many patients presenting with ischemic symptoms may have ST elevation (STE) at baseline, not all STE signify transmural ischemia. Benign patterns can be easy to find in some cases. However, patients with benign STE at baseline (left ventricular hypertrophy, early repolarization pattern) may have ongoing ischemia and present with Non-ST elevation myocardial infarction (NSTEMI) or even STEMI superimposed on the benign pattern. The ability of clinicians to distinguish between ischemic and non ischemic STE varies widely and is affected by prevalence of such changes in patient population. More studies need to be done to delineate the criteria to clearly distinguish between ischemic and non ischemic ST elevation.

Differentiating ST-elevation myocardial infarction from nonischemic ST-elevation in patients with chest pain

Current guidelines state that patients with compatible symptoms and ST-segment elevation (STE) in ≥2 contiguous electrocardiographic leads should undergo immediate reperfusion therapy. Aggressive attempts at decreasing door-to-balloon times have led to more frequent activation of primary percutaneous coronary intervention (pPCI) protocols. However, it remains crucial to correctly differentiate STE myocardial infarction (STEMI) from nonischemic STE (NISTE). We assessed the ability of experienced interventional cardiologists in determining whether STE represents acute STEMI or NISTE. Seven readers studied electrocardiograms of consecutive patients showing STE. Patients with left bundle branch block or ventricular rhythms were excluded. Readers decided if, based on electrocardiographic results, they would have activated the pPCI protocol. If NISTE was chosen, readers selected from 12 possible explanations as to why STE was present. Of 84 patients, 40 (48%) had adjudicated STEMI. The percentage for which readers recommended pPCI varied (33% to 75%). Readers' sensitivity and specificity ranged from 55% to 83% (average 71%) and 32% to 86% (average 63%), respectively. Positive and negative predictive values ranged from 52% to 79% (average 66%) and 67% to 79% (average 71%), respectively. Broad inconsistencies existed among readers as to the chosen reasons for NISTE classification. In conclusion, we found wide variations in experienced interventional cardiologists in differentiating STEMI with a need for pPCI from NISTE.

Serial prehospital 12-lead electrocardiograms increase identification of ST-segment elevation myocardial infarction

BACKGROUND

Many prehospital protocols require acquisition of a single 12-lead electrocardiogram (ECG) when assessing a patient for ST-segment elevation myocardial infarction (STEMI). However, it is known that ECG evidence of STEMI can evolve over time.

OBJECTIVES

To determine how often the first and, if necessary, second or third prehospital ECGs identified STEMI, and the time intervals associated with acquiring these ECGs and arrival at the emergency department (ED).

METHODS

We retrospectively analyzed 325 consecutive prehospital STEMIs identified between June 2008 and May 2009 in a large third-service emergency medical services (EMS) system. If the first ECG did not identify STEMI, protocol required a second ECG just before transport and, if necessary, a third ECG before entering the receiving ED. Paramedics who identified STEMI at any time bypassed participating local EDs, taking patients directly to the percutaneous coronary intervention (PCI) center. Paramedics used computerized ECG interpretation with STEMI diagnosis defined as an "acute MI" report by GE/Marquette 12-SL software in ZOLL E-series defibrillator/cardiac monitors (ZOLL Medical, Chelmsford, MA). We recorded the time of each ECG, and the ordinal number of the diagnostic ECG. We then determined the number of cases and frequency of STEMI diagnosis on the first, second, or third ECG. We also measured the interval between ECGs and the interval from the initial positive ECG to arrival at the ED. Results. STEMI was identified on the first prehospital ECG in 275 cases, on the second ECG in 30 cases, and on the third ECG in 20 cases (cumulative percentages of 84.6%, 93.8%, and 100%, respectively). For STEMIs identified on the second or third ECG, 90% were identified within 25 minutes after the first ECG. The median times from identification of STEMI to arrival at the ED were 17.5 minutes, 11.0 minutes, and 0.7 minutes for STEMIs identified on the first, second, and third ECGs, respectively.

CONCLUSIONS

A single prehospital ECG would have identified only 84.6% of STEMI patients. This suggests caution using a single prehospital ECG to rule out STEMI. Three serial ECGs acquired over 25 minutes is feasible and may be valuable in maximizing prehospital diagnostic yield, particularly where emergent access to PCI exists.

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.

Care Processes Associated With Quicker Door-In–Door-Out Times for Patients With ST-Elevation–Myocardial Infarction Requiring Transfer

Background—

The ability to rapidly identify patients with ST-segment elevation–myocardial infarction (STEMI) at hospitals without percutaneous coronary intervention (PCI) and transfer them to hospitals with PCI capability is critical to STEMI regionalization efforts. Our objective was to assess the association of prehospital, emergency department (ED), and hospital processes of care implemented as part of a statewide STEMI regionalization program with door-in–door-out times at non-PCI hospitals.

Methods and Results—

Door-in–door-out times for 436 STEMI patients at 55 non-PCI hospitals were determined before (July 2005 to September 2005) and after (January 2007 to March 2007) a year-long implementation of standardized protocols as part of a statewide regionalization program (Reperfusion of Acute Myocardial Infarction in North Carolina Emergency Departments, RACE). The association of 8 system care processes (encompassing emergency medical services [EMS], ED, and hospital settings) with door-in–door-out times was determined using multivariable linear regression. Median door-in–door-out times improved significantly with the intervention (before: 97.0 minutes, interquartile range, 56.0 to 160.0 minutes; after: 58.0 minutes, interquartile range, 35.0 to 90.0 minutes; P <0.0001). Hospital, ED, and EMS care processes were each independently associated with shorter door-in–door-out times (−17.7 [95% confidence interval, −27.5 to −7.9]; −10.1 [95% confidence interval, −19.0 to −1.1], and −7.3 [95% confidence interval, −13.0 to −1.5] minutes for each additional hospital, ED, and EMS process, respectively). Combined, adoption of EMS processes was associated with the shortest median treatment times (44 versus 138 minutes for hospitals that adopted all EMS processes versus none).

Conclusions—

Prehospital, ED, and hospital processes of care were independently associated with shorter door-in–door-out times for STEMI patients requiring transfer. Adoption of several EMS processes was associated with the largest reduction in treatment times. These findings highlight the need for an integrated, system-based approach to improving STEMI care.

Predictors of reperfusion delay in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention from the HORIZONS-AMI trial

Primary percutaneous coronary intervention (PCI) is the optimal method of reperfusion when performed expeditiously. Factors contributing to delays in PCI for ST-segment elevation myocardial infarction (STEMI) have not been thoroughly characterized or quantified. We sought to identify the factors associated with the delays to reperfusion in patients with STEMI undergoing primary PCI. Primary PCI was performed in 3,340 patients with STEMI in the international, multicenter Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction trial. Multivariate analysis was used to identify independent predictors of delay in achieving reperfusion from 38 baseline and procedural variables. A total of 905 patients (27.1%) presented to non-PCI hospitals and were subsequently transferred; the remainder presented to PCI hospitals. The most powerful independent predictor of the interval from symptom onset to arrival at the PCI hospital and the first door-to-balloon time was an initial presentation at a non-PCI hospital (median incremental 58- and 54-minute delay, respectively, both p < 0.001). Other independent predictors of prolonged door-to-balloon times included presentation with respiratory failure (42-minute incremental delay, p = 0.003), presentation during off-work hours (11-minute incremental delay, p < 0.001), and co-morbid conditions such as diabetes and heart failure. In conclusion, among patients undergoing primary PCI, presentation to a non-PCI hospital was the variable associated with the greatest delay to reperfusion. Systems of care that encourage ambulance diagnosis and direct delivery of patients with STEMI to a PCI hospital might shorten the overall door-to-balloon times and improve the clinical outcomes.

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.

Improving use of prehospital 12-lead ECG for early identification and treatment of acute coronary syndrome and ST-elevation myocardial infarction

BACKGROUND

Performance of prehospital ECGs expedites identification of ST-elevation myocardial infarction and reduces door-to-balloon times for patients receiving reperfusion therapy. To fully realize this benefit, emergency medical service performance must be measured and used in feedback reporting and quality improvement.

METHODS AND RESULTS

This quasi-experimental design trial tested an approach to improving emergency medical service prehospital ECGs using feedback reporting and quality improvement interventions in 2 cities' emergency medical service agencies and receiving hospitals. All patients age > or =30 years, calling 9-1-1 with possible acute coronary syndrome, were included. In total, 6994 patients were included: 1589 patients in the baseline period without feedback and 5405 in the intervention period when there were feedback reports and quality improvement interventions. Mean age was 66+/-17 years, and women represented 51%. Feedback and quality improvement increased prehospital ECG performance for patients with acute coronary syndrome from 76% to 93% (P=<0.0001) and for patients with ST-elevation myocardial infarction from 77% to 99% (P=<0.0001). Aspirin administration increased from 75% to 82% (P=0.001), but the median total emergency medical service run time remained the same at 22 minutes. The proportion of patients with door-to-balloon times of < or =90 minutes increased from 27% to 67% (P=0.006).

CONCLUSIONS

Feedback reports and quality improvement improved prehospital ECG performance for patients with acute coronary syndrome and ST-elevation myocardial infarction and increased aspirin administration without prehospital transport delays. Improvements in door-to-balloon times were also seen.

Underuse of prehospital strategies to reduce time to reperfusion for ST-elevation myocardial infarction patients in 5 Canadian provinces

OBJECTIVE

Timely reperfusion therapy for ST-elevation myocardial infarction (STEMI) is an important determinant of outcome, yet targets for time to treatment are frequently unmet in North America. Prehospital strategies can reduce time to reperfusion. We sought to determine the extent to which emergency medical services (EMS) use these strategies in Canada.

METHODS

We carried out a cross-sectional survey in 2007 of ground EMS operators in British Columbia, Alberta, Ontario, Quebec and Nova Scotia. We focused on the use of 4 prehospital strategies: 1) 12-lead electrocardiogram (ECG), 2) routine expedited emergency department (ED) transfer of STEMI patients (from a referring ED to a percutaneous coronary intervention [PCI] centre), 3) prehospital bypass (ambulance bypass of local EDs to transport patients directly to PCI centres) and 4) prehospital fibrinolysis.

RESULTS

Ninety-seven ambulance operators were surveyed, representing 15 681 paramedics serving 97% of the combined provincial populations. Of the operators surveyed, 68% (95% confidence interval [CI] 59%-77%) had ambulances equipped with 12-lead ECGs, ranging from 40% in Quebec to 100% in Alberta and Nova Scotia. Overall, 47% (95% CI 46%-48%) of paramedics were trained in ECG acquisition and 40% (95% CI 39%-41%) were trained in ECG interpretation. Only 18% (95% CI 10%-25%) of operators had prehospital bypass protocols; 45% (95% CI 35%-55%) had protocols for expedited ED transfer. Prehospital fibrinolysis was available only in Alberta. All EMS operators in British Columbia, Alberta and Nova Scotia used at least 1 of the 4 prehospital strategies, and one-third of operators in Ontario and Quebec used 0 of 4. In major urban centres, at least 1 of the 3 prehospital strategies 12-lead ECG acquisition, bypass or expedited transfer was used, but there was considerable variation within and across provinces.

CONCLUSION

The implementation of widely recommended prehospital STEMI strategies varies substantially across the 5 provinces studied, and relatively simple existing technologies, such as prehospital ECGs, are underused in many regions. Substantial improvements in prehospital services and better integration with hospital-based care will be necessary in many regions of Canada if optimal times to reperfusion, and associated outcomes, are to be achieved.

A method for improving arrival-to-electrocardiogram time in emergency department chest pain patients and the effect on door-to-balloon time for ST-segment elevation myocardial infarction

OBJECTIVES

The objectives were to determine if an emergency department (ED) could improve the adherence to a door-to-electrocardiogram (ECG) time goal of 10 minutes or less for patients who presented to an ED with chest pain and the effect of this adherence on door-to-balloon (DTB) time for ST-segment elevation myocardial infarction (STEMI) cardiac catheterization (cath) alert patients.

METHODS

This was a planned 1-month before-and-after interventional study design for implementing a new process for obtaining ECGs in patients presenting to the study ED with chest pain. Prior to the change, patients were registered and triaged before an ECG was obtained. The new procedure required registration clerks to identify those with chest pain and directly overhead page or call a designated ECG technician. This technician had other ED duties, but prioritized performing ECGs and delivering them to attending physicians. A full registration process occurred after the clinical staff performed their initial assessment. The primary outcome was the total percentage of patients with chest pain who received an ECG within 10 minutes of ED arrival. The secondary outcome was DTB time for patients with STEMI who were emergently cath alerted. Data were analyzed using mean differences, 95% confidence intervals (CIs), and relative risk (RR) regression to adjust for possible confounders.

RESULTS

A total of 719 patients were studied: 313 before and 405 after the intervention. The mean (+/-standard deviation [SD]) age was 50 (+/-16) years, 54% were women, 57% were African American, and 36% were white. Patients walked in 89% of the time; 11% arrived by ambulance. Thirty-nine percent were triaged as emergent and 61% as nonemergent. Patients presented during daytime 68% of the time, and 32% presented during the night. Before the intervention, 16% received an ECG at 10 minutes or less. After the intervention, 64% met the time requirement, for a mean difference of 47.3% (95% CI = 40.8% to 53.3%, p < 0.0001). Results were not affected by age, sex, race, mode of arrival, triage classification, or time of arrival. For patients with STEMI cath alerts, four were seen before and seven after the intervention. No patients before the intervention had ECG time within 10 minutes, and one of four had DTB time of <90 minutes. After the intervention, all seven patients had ECG time within 10 minutes; the three arriving during weekday hours when the cath team was on site had DTB times of <90 minutes, but the four arriving at night and on weekends when the cath team was off site had DTB times of >90 minutes.

CONCLUSIONS

The overall percentage of patients with a door-to-ECG time within 10 minutes improved without increasing staffing. An ECG was performed within 10 minutes of arrival for all patients who were STEMI cath alerted, but DTB time under 90 minutes was achieved only when the cath team was on site.

ST-elevation myocardial infarction patients can be enrolled in randomized trials before emergent coronary intervention without sacrificing door-to-balloon time

BACKGROUND

Multicenter trials are necessary to compare the effectiveness of new drugs and devices for patients with ST-elevation myocardial infarction (STEMI) percutaneous coronary intervention (PCI). However, enrollment of STEMI patients in clinical trials could be detrimental to patients if it significantly delayed reperfusion therapy. We sought to determine whether STEMI patients treated with PCI could be enrolled in clinical trials without prolonging door-to-balloon times.

METHODS

At a single PCI center between October 17, 2004, and December 31, 2007, patients were enrolled in 1 of 4 trials requiring central enrollment and informed consent if (1) a study was actively enrolling, (2) the patient met inclusion/exclusion criteria, (3) and a study nurse was available. Median door-to-balloon times were compared for patients enrolled in clinical trials compared to those not enrolled.

RESULTS

Of 581 STEMI patients treated with PCI, 123 were enrolled in clinical trials and 458 were not. For patients transferred for PCI, community hospital door-to-balloon times were similar for research and nonresearch patients (104 vs 108 minutes, P = .4). For patients presenting directly to the PCI center, median door-to-balloon times were similar for research (55 minutes) and nonresearch patients (44 minutes, P = .5) after adjustment for age, culprit artery, and operator.

CONCLUSIONS

Patients with STEMI may be enrolled in clinical trials with no significant delay in achieving reperfusion. For patients presenting directly to the PCI center, median door-to-balloon times well under 90 minutes can be achieved even with enrollment into clinical trials.

Effect of prehospital triage on revascularization times, left ventricular function, and survival in patients with ST-elevation myocardial infarction

Shorter reperfusion times lead to better outcomes in patients with ST-elevation myocardial infarction (STEMI). We assessed the efficacy of prehospital triage with bypass of community hospitals and early activation of the cardiac catheterization team on revascularization times, left ventricular (LV) ejection fraction, and survival. Patients with STEMI (624) were divided into 3 groups determined by site of triage: ambulance field triage (163), interventional center emergency department (202), and 3 community hospital emergency departments (259). Compared with community hospital and interventional center triages, ambulance field triage resulted in a significant median decrease in door-to-balloon times of 68 and 27 minutes, respectively (p <0.001). LV ejection fraction was highest in the field triage group (52 +/- 13%) compared with the interventional center (49 +/- 12%) and community hospital (48 +/- 12%, p = 0.017) groups. Thirty-day mortality was lowest in the ambulance field group (3%) compared with the interventional facility (11%) and community hospital (4%, p = 0.007) groups. There was a significant difference in long-term survival with up to 30-month follow-up among the 3 triage groups (p = 0.041). With time-dependent Cox regression modeling the difference in survival was significant only during the first week after STEMI (p = 0.020). Every extra minute of symptom onset to reperfusion time was associated with a relative risk of long-term mortality of 1.003 (95% confidence interval 1.000 to 1.006, p = 0.027). In conclusion, field triage of patient with STEMI decreased revascularization times, which preserved LV function, and improved early survival.

Elapsed time in emergency medical services for patients with cardiac complaints: are some patients at greater risk for delay?

BACKGROUND

In patients with a major cardiac event, the first priority is to minimize time to treatment. For many patients, first contact with the health system is through emergency medical services (EMS). We set out to identify patient-level and neighborhood-level factors that were associated with elapsed time in EMS.

METHODS AND RESULTS

A retrospective cohort study was conducted in 10 municipalities in Dallas County, Tex, from January 1 through December 31, 2004. The data set included 5887 patients with suspected cardiac-related symptoms. The region was served by 29 hospitals and 98 EMS depots. Multivariate models included measures of distance traveled, time of day, day of week, and patient and neighborhood characteristics. The main outcomes were elapsed time in EMS (continuous; in minutes) and delay in EMS (dichotomous; >15 minutes beyond median elapsed time). We found positive associations between patient characteristics and both average elapsed time and delay in EMS care. Variation in average elapsed time was not large enough to be clinically meaningful. However, approximately 11% (n=647) of patients were delayed >or=15 minutes. Women were more likely to be delayed (adjusted odds ratio, 1.52; 95% confidence interval, 1.32 to 1.74), and this association did not change after adjusting for other characteristics, including neighborhood socioeconomic composition.

CONCLUSIONS

Compared with otherwise similar men, women have 50% greater odds of being delayed in the EMS setting. The determinants of delay should be a special focus of EMS studies in which time to treatment is a priority.

Implementation of Guidelines for the Treatment of Acute ST-Elevation Myocardial Infarction

Background— The aim of the Köln (Cologne) Infarction Model is to examine the feasibility of obligatory treatment of ST-segment–elevation myocardial infarction (STEMI) by first-line percutaneous coronary intervention.

Methods and Results— The study was performed in Cologne with >1 million citizens, 5 coronary intervention centers, and 11 primary care hospitals. Twelve-lead ECG was available for all emergency medical service (EMS) teams. Partners guaranteed direct transfer of STEMI patients to a catheterization laboratory. A total of 519 patients treated within KIM in 2006 were included in the study. Of these, 24% presented at a primary care hospital, 11% presented directly at a coronary intervention center, 5% were transferred by EMS to primary care hospitals, and 60% were directly transferred by EMS to a catheterization laboratory. In 91% of cases, the catheterization laboratory was notified of the patient’s arrival in advance. False-positive ECG diagnosis of STEMI by EMS accounted for 6%. Median treatment times were as follows: from the start of symptoms to first medical contact, 120 minutes; phone to balloon, 70 minutes; and door to balloon, 49 minutes. Of all patients, 93% underwent angiography; 409 patients were treated by coronary intervention, and 24 underwent emergency coronary artery bypass graft. Thrombolysis in Myocardial Infarction grade 3 flow was obtained in 89%. In the hospitals, deaths and new myocardial infarctions were observed in 12.1% and in 1.9% of all patients, respectively.

Conclusion— The Cologne Infarction Model provides evidence for the feasibility of obligatory treatment of STEMI by primary coronary intervention in a metropolitan setting. Acceptance of treatment pathways allowed nearly all STEMI patients to undergo coronary angiography. ECG competence of EMS was excellent. Treatment times were within postulated limits. Results, including mortality, were within a high quality range.