Use of emergency medical services in acute myocardial infarction and subsequent quality of care: observations from the National Registry of Myocardial Infarction 2

Trends in reperfusion strategies, door-to-needle and door-to-balloon times, and in-hospital mortality among patients with ST-segment elevation myocardial infarction enrolled in the National Registry of Myocardial Infarction from 1990 to 2006

BACKGROUND

Among patients with ST-segment elevation myocardial infarction (STEMI), rapid reperfusion is associated with improved mortality. As such, door-to-needle (D2N) and door-to-balloon (D2B) times have become metrics of quality of care and targets for intense quality improvement.

METHODS

The National Registry of Myocardial Infarction (NRMI) collected data regarding reperfusion therapy, its timing and in-hospital mortality among STEMI patients from 1990 through 2006.

RESULTS

Since 1990, NRMI has enrolled 1,374,232 STEMI patients at 2,157 hospitals. Among those, 774,279 (56.3%) were eligible for reperfusion upon arrival. The proportion receiving fibrinolytic therapy fell from 52.5% in 1990 to 27.6% in 2006 (P < .001), while the proportion undergoing primary percutaneous coronary intervention (pPCI) increased from 2.6% to 43.2%. Among reperfusion-eligible patients who received fibrinolytic therapy, there was a nearly linear decline in median D2N time from 59 minutes in 1990 to 29 minutes in 2006 (P < .001 for trend) as well as a decrease in mortality from 7.0% in 1994 to 6.0% in 2006 (P < .001). Among those undergoing pPCI, D2B time among nontransfer patients declined linearly from 111 minutes in 1994 to 79 minutes in 2006 (P < .001) with a decline in mortality from 8.6% to 3.1% (P < .001). The relative improvement in mortality attributable to improvements in D2N time was 16.3% and to D2B time was 7.5%.

CONCLUSIONS

Since 1990, there has been a progressive decline in D2N and D2B time among reperfusion-eligible STEMI patients. These improvements have contributed, at least in part, to a progressive decline in mortality.

Factors that influence the use of ambulance in acute coronary syndrome

BACKGROUND

National guidelines recommend activation of the emergency medical service by patients who have symptoms of acute coronary syndrome (ACS). In spite of this, only 50% to 60% of persons with myocardial infarction initiate care by using the emergency medical service. The aim of this study was to define factors influencing the use of ambulance in ACS.

METHODS

The method used in this study was a national survey comprising intensive cardiac care units at 11 hospitals in Sweden; 1,939 patients with diagnosed ACS and symptom onset outside the hospital completed a questionnaire a few days after admission.

RESULTS

Half of the patients went to the hospital by ambulance. Factors associated with ambulance use were knowledge of the importance of quickly seeking medical care and calling for an ambulance when having chest pain (odds ratio [OR] 3.61, 95% CI 2.43-5.45), abrupt onset of pain reaching maximum intensity within minutes (OR 2.08, 1.62-2.69), nausea or cold sweat (OR 2.02, 1.54-2.65), vertigo or near syncope (OR 1.63, 1.21-2.20), ST-elevation ACS (OR 1.58, 1.21-2.06), increasing age (per year) (OR 1.03, 1.02-1.04), previous history of heart failure (OR 2.48, 1.47-4.26), and distance to the hospital of >5 km (OR 2.0, 1.55-2.59). Those who did not call for an ambulance thought self-transport would be faster or did not believe they were sick enough.

CONCLUSIONS

Symptoms, patient characteristics, ACS characteristics, and perceptions and knowledge were all associated with ambulance use in ACS. The fact that knowledge increases ambulance use and the need for behavioral change pose a challenge for health-care professionals.

Prehospital transport of patients with acute myocardial infarction: a community-wide perspective

OBJECTIVE

The objectives of this population-based study were to examine the use of emergency medical services (EMS) in greater Worcester, Massachusetts, residents (2000 census = 478,000) hospitalized with acute myocardial infarction (AMI) at all metropolitan Worcester medical centers in four biennial periods between 1997 and 2003. A secondary study aim was to describe the demographic and clinical characteristics of patients with AMI transported to metropolitan Worcester hospitals by EMS, compared with those transported by other means, and their hospital outcomes.

METHODS

We reviewed the medical records of 3805 patients hospitalized for confirmed AMI at 11 greater Worcester medical centers during 1997, 1999, 2001, and 2003. Information about the use of EMS, patient characteristics, and hospital outcomes was obtained through the review of hospital charts.

RESULTS

A total of 2693 greater Worcester residents with AMI (70.8%) were transported to area hospitals by ambulance. Patients transported by ambulance were older, were more likely to be women, had a greater prevalence of comorbidities, and had a different symptom profile than patients transported by other means. Patients arriving at greater Worcester hospitals by ambulance were more likely to develop serious clinical complications, including heart failure and cardiogenic shock, and die during hospitalization compared with patients not transported by EMS.

CONCLUSIONS

Our results suggest that the majority of greater Worcester residents seeking care for AMI are transported by EMS. Patients transported by ambulance differ from patients transported by other means and are more likely to experience adverse hospital outcomes. The reasons why patients use EMS in the setting of AMI need to be further explored and patients' care-seeking behavior enhanced.

Effect of prehospital 12-lead electrocardiogram on activation of the cardiac catheterization laboratory and door-to-balloon time in ST-segment elevation acute myocardial infarction

Reducing door-to-balloon (D + B) time during primary percutaneous coronary intervention for patients with ST-segment elevation myocardial infarction (STEMI) reduces mortality. Prehospital 12-lead electrocadiography (ECG) with cardiac catheterization laboratory (CCL) activation may reduce D + B time. Paramedic-performed ECG was initiated in the city of San Diego in January 2005 with STEMI diagnosis based on an automated computer algorithm. We undertook this study to determine the effect of prehospital CCL activation on D + B time for patients with acute STEMI brought to our institution. All data were prospectively collected for patients with STEMI including times to treatment and clinical outcomes. We evaluated 78 consecutive patients with STEMI from January 2005 to June 2006, and the study group consisted of all patients with prehospital activation of the CCL (field STEMI; n = 20). The control groups included concurrently-treated patients with STEMI during the same period who presented to the emergency department (nonfield STEMI; n = 28), and all patients with STEMI treated in the preceding year (2004) (historical STEMI; n = 30). Prehospital CCL activation significantly reduced D + B time (73 +/- 19 minutes field STEMI, 130 +/- 66 minutes nonfield STEMI, 141 +/- 49 minutes historical STEMI; p <0.001) with significant reductions in door-to-CCL and CCL-to-balloon times as well. The majority of patients with field STEMI achieved D + B times of <90 minutes (80% field STEMI, 25% nonfield STEMI, 10% historical STEMI; p <0.001). In conclusion, this study demonstrates that prehospital electrocardiographic diagnosis of STEMI with activation of the CCL markedly reduces D + B time.

Contact-to-balloon time and door-to-balloon time after initiation of a formalized data feedback in patients with acute ST-elevation myocardial infarction

For many patients with ST-segment elevation myocardial infarctions (STEMIs), the time from presentation to percutaneous coronary intervention exceeds established goals. This study was conducted to examine the effects of formalized data assessment and systematic feedback on treatment times. All patients with STEMIs treated with percutaneous coronary intervention in a semi-rural 3-hospital network from January 1, 2006, to December 31, 2006, were prospectively analyzed (n = 114). Patients presenting during the first 3-month period (January 1, 2006, to March 31, 2006) were included as the reference group (n = 33). Time points from initial contact with the medical system to revascularization were assessed, analyzed, and presented in an interactive session to hospital and emergency services staff members. Data from patients with STEMIs presenting during the next 3 quarters were presented in the same manner (n = 28, 25, and 28). The median contact-to-balloon time was 113 minutes in the reference quarter, decreasing to 83, 66, and 74 minutes in the intervention groups (p <0.0001), whereas the median door-to-balloon time decreased from 54 minutes in the reference group to 35, 31, and 26 minutes in the intervention groups (p <0.0001). The proportion of patients with contact-to-balloon times <90 minutes increased from 21% to 79% (p <0.0001). There were significant reductions in the durations of initial treatment on location and in the emergency room and in puncture-to-balloon-time in the catheterization laboratory, and more patients were transported directly to the catheterization laboratory, bypassing the emergency room (from 23% in the reference quarter to 76% in the last intervention quarter, p <0.0001). In conclusion, formalized data feedback leads to marked reduction in revascularization times in patients with STEMIs.

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.

Improvement in door-to-balloon times in management of acute ST-segment elevation myocardial infarction STEMI through the initiation of 'Code AMI'

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) mandates rapid percutaneous coronary intervention (PCI) for optimal outcomes. The aim of this study was to assess our hospital practice for managing acute STEMI, identify processes associated with time delays, instrument changes to our acute STEMI management protocol and assess their effectiveness for improving our door-to-balloon time.

METHODS

We aimed to achieve this through the establishment of a quality improvement programme involving the cardiology and emergency departments. We analysed consecutive patients presenting with STEMI (April to September 2005 (group A) and the corresponding period in 2006 (group B), and compared patients presenting 'in hours' (0700 hours to 1800 hours (Monday to Friday)) versus 'out of hours' (all other times including public holidays).

RESULTS

In group A, 38 patients presented with a STEMI. Assessing time-to-treatment analysis, the median door to balloon time for primary PCI was significantly greater for 'out of hours' than 'in hours' (120 vs 67 min). The greatest time delay to PCI was from the PCI decision time to catheter laboratory arrival. Local changes were implemented to improve 'out of hours' times, including initiation of 'Code AMI'. There were 59 patients in group B. We found that our changes led to a 29% improvement in 'out of hours' door-to-balloon time (median time 82 min, P = 0.005) with 69% being managed < or =90 min (P = 0.049) (group B).

CONCLUSION

We have shown that ongoing review through a quality improvement programme improves door-to-balloon times, which is integral in the optimal management of patients with acute STEMI treated with primary PCI.

Usefulness of acoustic cardiography to resolve ambiguous values of B-type natriuretic Peptide levels in patients with suspected heart failure

B-type natriuretic peptide (BNP) levels are helpful to diagnose left ventricular (LV) systolic and/or diastolic dysfunction. BNP levels that are only moderately increased have limited diagnostic ability, and an additional test to resolve this problem would be desirable. The hypothesis that acquiring combined electrocardiographic and electronic cardiac acoustical data can improve the detection of LV dysfunction in patients with nondiagnostic values of BNP was tested. Both BNP and combined 12-lead electrocardiograms with electronic heart sound (acoustic cardiographic) recordings were obtained from 164 outpatients referred for echocardiographic evaluation for suspected heart failure. Acoustic cardiographic parameters included the third heart sound (S(3)) and percentage of electromechanical activation time, measured as the interval from onset of the Q wave of the electrocardiogram to the first heart sound (S(1)) and expressed as a proportion of the cardiac cycle. Sixty-nine of 164 patients (42%) had BNP values in the "gray zone" of 100 to 500 pg/ml. Sensitivity and specificity for LV dysfunction of BNP in the gray zone were 55% and 75%, with a positive likelihood ratio of 2.3. The use of acoustic cardiographic parameters in these 69 patients increased sensitivity and specificity to 69% and 100%, with a corresponding positive likelihood ratio of 69. In conclusion, easily obtainable acoustic cardiographic data substantially improved the diagnostic evaluation of patients with nondiagnostic BNP values and therefore can increase the confidence with which physicians diagnose and treat LV dysfunction.

Emergency Department Physician Activation of the Catheterization Laboratory and Immediate Transfer to an Immediately Available Catheterization Laboratory Reduce Door-to-Balloon Time in ST-Elevation Myocardial Infarction

Background— Consensus guidelines and hospital quality-of-care programs recommend that ST-elevation myocardial infarction patients achieve a door-to-balloon time of ≤90 minutes. However, there are limited prospective data on specific measures to significantly reduce door-to-balloon time.

Methods and Results— We prospectively determined the impact on median door-to-balloon time of a protocol mandating (1) emergency department physician activation of the catheterization laboratory and (2) immediate transfer of the patient to an immediately available catheterization laboratory by an in-house transfer team consisting of an emergency department nurse, a critical care unit nurse, and a chest pain unit nurse. We collected door-to-balloon time for 60 consecutive ST-elevation myocardial infarction patients undergoing emergency percutaneous intervention within 24 hours of presentation from October 1, 2004, through August 31, 2005, and compared this group with 86 consecutive ST-elevation myocardial infarction patients from September 1, 2005, through June 26, 2006, after protocol implementation. Median door-to-balloon time decreased overall (113.5 versus 75.5 minutes; P <0.0001), during regular hours (83.5 versus 64.5 minutes; P =0.005), during off-hours (123.5 versus 77.5 minutes; P <0.0001), and with transfer from an outside affiliated emergency department (147 versus 85 minutes; P =0.0006). Treatment within 90 minutes increased from 28% to 71% ( P <0.0001). Mean infarct size decreased (peak creatinine kinase, 2623±3329 versus 1517±1556 IU/L; P =0.0089), as did hospital length of stay (5±7 versus 3±2 days; P =0.0097) and total hospital costs per admission ($26 826±29 497 versus $18 280±8943; P =0.0125).

Conclusions— Emergency department physician activation of the catheterization laboratory and immediate transfer of the patient to an immediately available catheterization laboratory reduce door-to-balloon time, leading to a reduction in myocardial infarct size, hospital length of stay, and total hospital costs.

Time to reperfusion in acute myocardial infarction. It is time to reduce it!

BACKGROUND AND OBJECTIVES

Mortality from ST-segment elevation myocardial infarction remains high, with most deaths occurring before hospital admission. Despite effective pre- and in-hospital reperfusion strategies becoming standard over the past 2 decades, time-to-admission and time-to-treatment remain prolonged. We reviewed temporal trends in these times in published clinical trials.

METHODS

All major randomized clinical trials reporting on reperfusion strategies for acute myocardial infarction published between 1993 and 2003 were evaluated. Strategies included pre- and in-hospital thrombolysis, primary percutaneous coronary intervention (pPCI) with or without transfer, and "facilitated" PCI. We generated overall estimates of time-to-admission, time-to-treatment, door-to-balloon (DTB), and door-to-needle (DTN) times and evaluated temporal trends in the length of time-to-admission and time-to-treatment.

RESULTS

In studies that evaluated only in-hospital thrombolysis, the time-to-admission was 149 +/- 45 minutes; the mean time-to-treatment was 181 +/- 29 minutes. In studies that considered only in-hospital pPCI (without transfer), the mean time-to-admission was 153 +/- 41 minutes; the mean time-to-treatment was 234 +/- 43 minutes. In studies that compared in-hospital pPCI with in-hospital thrombolytic therapy, the mean time-to-admission was 155 +/- 47 and 150 +/- 48 minutes, respectively. The DTN time was 65 +/- 10 minutes, whereas DTB time was 81 +/- 39 minutes. In other trials evaluating in-hospital thrombolysis and pPCI with transfer to a referral center, the time-to-admission in subjects treated with thrombolysis (n = 1345) was 127 +/- 32 minutes vs 131 +/- 36 minutes for pPCI (n = 1528). For in-hospital thrombolysis, time-to-treatment was 151 +/- 23 minutes vs 203 +/- 15 minutes for pPCI patients with transfer. The DTN time in the thrombolysis group was 44 +/- 28 minutes as compared with DTB time of 78 +/- 38 minutes in the pPCI group. Throughout the last decade, time-to-admission decreased significantly (P = .02) but time-to-treatment remained unchanged (P = .38) for patients undergoing thrombolysis. In the pPCI arm, time-to-admission remained unchanged (P = .11) but a insignificant trend toward reduction was demonstrated in time-to-treatment (P = .11).

CONCLUSION

Time-to-admission and time-to-treatment for ST-segment elevation myocardial infarction are still prolonged. Resources should be directed to early recognition of the acute myocardial infarction, improved utilization of emergency services for transportation, and prehospital diagnosis and triaging. Ambulances equipped with wireless capability to transmit electrocardiograms to the on-call cardiologist seem to be promising tools to achieve earlier diagnosis and triaging with high diagnostic sensitivity and specificity.

Prehospital evaluation and treatment of a presumed acute coronary syndrome: what are the options?

The earlier infarct-limiting therapy is started the better is the outcome among patients suffering from a threatened myocardial infarction. The introduction of a prehospital electrocardiogram has improved triage of patients with acute chest pain. With regard to medication, fibrinolytic agents have the best documentation. Their use when frequently followed by a percutaneous coronary intervention at a later stage may be a good alternative among patients with ST-elevation myocardial infarction. Other treatments of potential value in the prehospital setting are oxygen, narcotic analgesics, nitrates, aspirin, heparin, low molecular weight heparin, glycoprotein IIB, IIIA blockers, clopidogrel and beta-blockers. We need further studies, however, for most of these treatments including cost-benefit analysis, analysis of various logistic aspects and safety in order to confirm their value.

Characteristics and outcome of patients with acute chest pain in relation to the use of ambulances in an urban and a rural area

PURPOSE

The aim of the study was to evaluate the rate of ambulance use and the long-term prognosis in acute chest pain in an urban and a rural area and whether there is a difference between an urban and a rural area.

PROCEDURES

Patients with acute chest pain consecutively admitted to Sahlgrenska University Hospital (a city hospital) and Uddevalla County Hospital between November 1996 and April 1997 were followed up prospectively for 5 years.

RESULTS

In the city hospital, 688 (36%) of 1907 patients were transported by ambulance as compared with 369 (44%) of 842 patients in the county hospital. The patients transported by ambulance were much older (mean, 71 vs 59 years in both areas), and the comorbidity was more severe among patients transported by ambulance in both areas. In the city hospital, the 5-year mortality was 41.8% among those transported by ambulance and 15.8% among those transported by other means (P < .0001). The corresponding figures for the county hospital were 38.7% and 11.0% with a P value of less than .0001.

CONCLUSIONS

During the 1990s, patients with acute chest pain who were transported to a hospital by ambulance differed markedly in characteristics and outcome when compared with patients transported by other means. Results did not differ with regard to area.

Predictors of ambulance use in patients with acute myocardial infarction in Australia

AIMS

To determine ambulance transport rates and investigate predictors for ambulance use by patients with acute myocardial infarction (AMI) in Australia.

METHODS

A prospective, cross-sectional descriptive survey using structured interviews. It included patients who were admitted to two hospitals (Western, Bendigo, Melbourne, Victoria, Australia) with AMI between 1 October 2004 and 31 March 2005, and data were collected by semistructured interview and medical record review. Data were analysed by descriptive statistics, univariate and multivariate analysis using SPSS.

RESULTS

105 patients were interviewed. 48 (46%) participants called for an ambulance as their initial medical contact. Participants who called for an ambulance had a shorter interval between symptom onset and presentation to hospital than those who did not (non-ambulance participants)(median 2.1 v 7.8 h; p = 0.001). Predictors of ambulance transport were older age (p = 0.008), symptom onset on the weekend (p = 0.022), presence of sharp chest pain (p = 0.011), self-administered anginine (p = 0.007), symptom onset at home (p = 0.027) and having a lower income (<dollarsA20 000; p = 0.022). After multivariate analysis, self-administered anginine, sharp chest pain and occurrence of symptom onset at home remained as independent predictors of ambulance use.

CONCLUSION

A substantial number of patients do not call for an ambulance as their first medical contact after the onset of AMI symptoms. Public education on the benefits of ambulance transport and early treatment, as well as recognition of AMI symptoms, is required.

Predictors of in-hospital delay to reperfusion in patients with acute myocardial infarction in Japan

The purpose of this study was to identify factors associated with in-hospital delay in patients with acute myocardial infarction (AMI) in Japan. In this observational study, 155 consecutive patients admitted with AMI to one of five urban hospitals were studied. The median door-to-needle time and door-to-catheterization-laboratory time was 19 min and 60 min, respectively. Three variables predicted door-to-catheterization-laboratory times >/= 60 min: failing to call an ambulance, direct admission to the hospital, and absence of diaphoresis (p < 0.05). These findings support the need for public education emphasizing the importance of calling an ambulance for AMI symptoms. Moreover, Japanese physicians should be aware that admitting patients directly to the hospital and bypassing the Emergency Department might increase delay to treatment.

Real-Time Detection and Alerting for Acute ST-Segment Elevation Myocardial Ischemia Using an Implantable, High-Fidelity, Intracardiac Electrogram Monitoring System With Long-Range Telemetry in an Ambulatory Porcine Model

OBJECTIVES

The purpose of this study was to evaluate feasibility of using real-time, high-fidelity, intracardiac electrogram monitoring from a permanently implantable ischemia detection system (IIDS), with long-range telemetry capability to detect ST-segment shifts associated with acute or subacute coronary occlusion in a porcine model.

BACKGROUND

Early identification of coronary occlusion with ST-segment elevation could profoundly accelerate the timing of revascularization and improve clinical outcomes.

METHODS

This paper reports the first investigation using real-time, high-fidelity, intracardiac electrogram monitoring from a permanently IIDS, with long-range telemetry capability. This IIDS was tested in an ambulatory porcine model, with acute coronary occlusion precipitated by stent thrombosis. Two overlapping copper stents were implanted in the left anterior descending (n = 3), the circumflex (n = 3), or the right coronary artery (n = 2) of juvenile farm pigs. Monitoring was carried using telemetry from the IIDS.

RESULTS

All stented pigs had acute ST-segment elevation event(s) triggering the alerting thresholds of the IIDS. All triggered events were confirmed to be caused by thrombosis of the copper stent(s), and well correlated to infarct age and location. Four of the 8 pigs died from ventricular fibrillation, recorded by the IIDS at a mean time of 70 +/- 121 h after ST-segment alert. The sensitivity and specificity of alerting for ST-segment shift, associated with thrombotic coronary occlusion, were 100% and 100%, respectively.

CONCLUSIONS

This study demonstrates the ability of an implantable ischemia detection system to detect ST-segment elevation from coronary occlusion in a porcine model of ST-segment elevation myocardial infarction. ST-segment elevation was sufficient to trigger alerting thresholds in all 3 epicardial coronary distributions. Such a system, with real-time alerting capability, could advance the time frame of reperfusion therapy and potentially prevent, rather than interrupt, acute myocardial infarction in patients with coronary artery disease.

Strategies for reducing the door-to-balloon time in acute myocardial infarction

BACKGROUND

Prompt reperfusion treatment is essential for patients who have myocardial infarction with ST-segment elevation. Guidelines recommend that the interval between arrival at the hospital and intracoronary balloon inflation (door-to-balloon time) during primary percutaneous coronary intervention should be 90 minutes or less. However, few hospitals meet this objective. We sought to identify hospital strategies that were significantly associated with a faster door-to-balloon time.

METHODS

We surveyed 365 hospitals to determine whether each of 28 specific strategies was in use. We used hierarchical generalized linear models and data on patients from the Centers for Medicare and Medicaid Services to determine the association between hospital strategies and the door-to-balloon time.

RESULTS

In multivariate analysis, six strategies were significantly associated with a faster door-to-balloon time. These strategies included having emergency medicine physicians activate the catheterization laboratory (mean reduction in door-to-balloon time, 8.2 minutes), having a single call to a central page operator activate the laboratory (13.8 minutes), having the emergency department activate the catheterization laboratory while the patient is en route to the hospital (15.4 minutes), expecting staff to arrive in the catheterization laboratory within 20 minutes after being paged (vs. >30 minutes) (19.3 minutes), having an attending cardiologist always on site (14.6 minutes), and having staff in the emergency department and the catheterization laboratory use real-time data feedback (8.6 minutes). Despite the effectiveness of these strategies, only a minority of hospitals surveyed were using them.

CONCLUSIONS

Several specific hospital strategies are associated with a significant reduction in the door-to-balloon time in the management of myocardial infarction with ST-segment elevation.

Comparison of early mortality of paramedic-diagnosed ST-segment elevation myocardial infarction with immediate transport to a designated primary percutaneous coronary intervention center to that of similar patients transported to the nearest hospital

Speed of reperfusion is critical in ST-segment elevation myocardial infarction (STEMI). We assessed the safety and feasibility of an integrated metropolitan approach in which advanced-care paramedics interpret the prehospital electrocardiogram and independently refer patients with STEMI to a designated center for primary percutaneous coronary intervention (PCI). We developed and implemented a protocol in which paramedics trained in electrocardiographic interpretation bypassed the nearest emergency room and referred patients with suspected STEMI directly to a designated primary PCI center (paramedic-referred primary PCI). Outcomes of these patients were compared with those of a retrospective cohort of 225 consecutive patients with STEMI transported by ambulance to the nearest hospital emergency department. We treated 108 consecutive patients with STEMI using ambulance services according to the paramedic-referred primary PCI protocol. Primary PCI was performed in 93.5% versus 8.9% in the control group, and the median door-to-balloon time was 63 versus 125 minutes in the control group (p <0.0001 for 2 comparisons). Thrombolytic therapy was prescribed to 80.4% of the control group, with a median door-to-needle time of 41 minutes. In-hospital mortality was 1.9% in the paramedic-referred primary PCI group versus 8.9% in the control group (p = 0.017) and remained significantly lower after statistical adjustment for baseline risk. In conclusion, paramedic-referred primary PCI is a safe and feasible strategy for treating STEMI that is associated with rapid and effective reperfusion and very low in-hospital mortality.

Broken bodies, broken hearts? Limitations of the trauma system as a model for regionalizing care for ST-elevation myocardial infarction in the United States

Many cardiovascular experts have called for the creation of specialized myocardial infarction centers and networks in the United States analogous to the current model for major trauma. Patients suffering ST-elevation myocardial infarction (STEMI) and trauma share an essential feature that makes the argument for regionalization persuasive: rapid triage and treatment by highly trained personnel improve survival in both conditions. Despite this similarity, however, the trauma system may be limited as a model for regionalizing STEMI care. First, the development of trauma systems has been hindered by the struggle for sufficient and stable funding, competing interests among individual stakeholders, and the overall lack of desire for state-sponsored healthcare planning in the United States. These same obstacles would need to be overcome if STEMI care is regionalized. Second, unique characteristics related to STEMI care, such as its varied clinical presentation and more lucrative reimbursement, will create new challenges. In this article, we briefly review the current status of trauma systems in the United States and describe why the regionalization of STEMI care may require different methods of healthcare organization.

Rationale for establishing regional ST-elevation myocardial infarction receiving center (SRC) networks

Recent developments have provided a unique opportunity for the organization of regional ST-elevation myocardial infarction (STEMI) receiving center (SRC) networks. Because cumulative evidence has demonstrated that rapid primary percutaneous coronary intervention (PCI) is the most effective reperfusion strategy for acute STEMI, the development of integrated SRC networks could extend the benefits of primary PCI to a much larger segment of the US population. Factors that favor the development of regional SRC networks include results from recently published clinical trials, insight into contemporary STEMI treatment patterns from observational registries, experience with the nation's current trauma system, and technological advances. In addition, the 2004 American College of Cardiology/American Heart Association STEMI guidelines have specified that optimal "first medical contact-to-balloon" times should be <90 minutes, so a clear benchmark for timely reperfusion has been established. Achievement of this benchmark will require improvements in the current process of care as well as increased multidisciplinary cooperation between emergency medical services, emergency medicine physicians, and cardiologists. Two types of regional SRC networks have already begun to evolve in role-model cities, including prehospital cardiac triage and interhospital transfer. Regional coordination of SRC networks is needed to ensure quality monitoring and to delineate the ideal reperfusion strategy for a given community based on available resources and expertise.

Bypassing the emergency room reduces delays and mortality in ST elevation myocardial infarction: the USIC 2000 registry

OBJECTIVE

To study the impact on outcomes of direct admission versus emergency room (ER) admission in patients with ST-segment elevation myocardial infarction (STEMI) DESIGN: Nationwide observational registry of STEMI patients

SETTING

369 intensive care units in France.

INTERVENTIONS

Patients were categorised on the basis of the initial management pathway (direct transfer to the coronary care unit or catheterisation laboratory versus transfer via the ER).

MAIN OUTCOME MEASURES

Delays between symptom onset, admission and reperfusion therapy. Mortality at five days and one year.

RESULTS

Of 1204 patients enrolled, 66.9% were admitted direct and 33.1% via the ER. Bypassing the ER was associated with more frequent use of reperfusion (61.7% v 53.1%; p = 0.001) and shorter delays between symptom onset and admission (244 (interquartile range 158) v 292 (172) min; p < 0.001), thrombolysis (204 (150) v 258 (240) min; p < 0.01), hospital thrombolysis (228 (156) v 256 (227) min, p = 0.22), and primary percutaneous coronary intervention (294 (246) v 402 (312) min; p < 0.005). Five day mortality rates were lower in patients who bypassed the ER (4.9% v 8.6%; p = 0.01), regardless of the use and type of reperfusion therapy. After adjusting for the simplified Thrombolysis in Myocardial Infarction (TIMI) risk score, admission via the ER was an independent predictor of five day mortality (odds ratio 1.67, 95% confidence interval 1.01 to 2.75).

CONCLUSIONS

In this observational analysis, bypassing the ER was associated with more frequent and earlier use of reperfusion therapy, and with an apparent survival benefit compared with admission via the ER.

Efficacy and safety of unfractionated heparin versus enoxaparin: a pooled analysis of ASSENT-3 and -3 PLUS data

BACKGROUND

The optimal antithrombotic therapy to accompany tenecteplase in cases of acute ST-segment elevation myocardial infarction (STEMI) remains unclear. We undertook a prespecified pooled analysis of data from the ASSENT-3 and ASSENT-3 PLUS trials.

METHODS

We created a combined database of the 2040 and 818 patients who received enoxaparin in ASSENT-3 and ASSENT-3 PLUS, respectively, and compared them with the 2038 and 821 patients who received unfractionated heparin.

RESULTS

The efficacy end point (a composite of 30-day mortality, reinfarction or refractory ischemia) was 12.2% with enoxaparin versus 16.0% with unfractionated heparin (p < 0.001); the combined end point of efficacy plus safety (a composite of 30-day mortality, reinfarction, refractory ischemia, intracranial hemorrhage [ICH] or major systemic bleeding) was 15.0% versus 18.0%, respectively (p = 0.003) [corrected] The 1049 patients urgently revascularized had greater benefit from enoxaparin (15.4% v. 10.1%, p = 0.013), yet the excess in major systemic bleeding evident with enoxaparin (3.3% v. 2.4%, p = 0.01) was largely confined to the 3492 patients without or before revascularization. Although ICH rates in the groups were similar (1.3% v. 0.9%, p = 0.26), an excess of ICH occurred among those administered enoxaparin during the ASSENT-3 PLUS trial (6.7% v. 0.8%, p = 0.013), especially among women over 75 years of age.

INTERPRETATION

These data demonstrated the benefit of enoxaparin used in conjunction with tenecteplase, but raised caution about its prehospital use to treat STEMI in elderly women.

Pre-hospital thrombolysis delivered by paramedics is associated with reduced time delay and mortality in ambulance-transported real-life patients with ST-elevation myocardial infarction

AIMS

There are sparse data on the impact of pre-hospital thrombolysis (PHT) in real-life patients. We therefore evaluated treatment delays and outcome in a large cohort of ambulance-transported real-life patients with ST-elevation myocardial infarction (STEMI) according to PHT delivered by paramedics or in-hospital thrombolysis.

METHODS AND RESULTS

Prospective cohort study used data from the Swedish Register of Cardiac intensive care on patients admitted to the coronary care units of 75 Swedish hospitals in 2001-2004. Ambulance-transported thrombolytic-treated patients younger than age 80 with a diagnosis of acute myocardial infarction were included. Patients with PHT (n=1690) were younger, had a lower prevalence of co-morbid conditions, fewer complications, and a higher ejection fraction (EF) than in-hospital-treated patients (n=3685). Median time from symptom onset to treatment was 113 min for PHT and 165 min for in-hospital thrombolysis. One-year mortality was 7.2 vs. 11.8% for PHT and in-hospital thrombolysis, respectively. In a multivariable analysis, after adjusting for baseline characteristics and rescue angioplasty, PHT was associated with lower 1-year mortality (odds ratio 0.71, 0.55-0.92, P=0.008).

CONCLUSION

When compared with regular in-hospital thrombolysis, pre-hospital diagnosis and thrombolysis with trained paramedics in the ambulances are associated with reduced time to thrombolysis by almost 1 h and reduced adjusted 1-year mortality by 30% in real-life STEMI patients.

A community intervention by firefighters to increase 911 calls and aspirin use for chest pain

OBJECTIVES

To test the effectiveness of an intervention, delivered face-to-face by local firefighters, designed to increase utilization of 911 and self-administration of aspirin for seniors experiencing chest pain.

METHODS

King County, Washington was divided into 126 geographically distinct areas that were randomized to intervention and control areas. A mailing list identified households of seniors within these areas. More than 20,000 homes in the intervention areas were contacted by local firefighters. Data on all 911 calls for chest pain and self-administration of aspirin were collected from the medical incident report form (MIRF). The unit of analysis was the area. Firefighters delivered a heart attack survival kit (that included an aspirin) and counseled participants on the importance of aspirin and 911 use for chest pain. Main outcome measures were 911 calls for chest pain and aspirin ingestion for a chest pain event, obtained from the MIRFs that are collected by emergency medical services personnel for 2 years after the intervention.

RESULTS

There were significantly more calls (16%) among seniors on the mailing list in the intervention than control areas in the first year after the intervention. Among the seniors who were not on the mailing list, there was little difference in the intervention and control areas. The results were somewhat sensitive to the analytical model used and to an outlier in the treatment group.

CONCLUSIONS

A community-based firefighter intervention can be effective in increasing appropriate response to symptoms of a heart attack among elders.

ST-Segment Elevation Myocardial Infarction: Recommendations on Triage of Patients to Heart Attack Centers

Despite substantial progress in the diagnosis and treatment of acute ST-segment elevation myocardial infarction (STEMI), implementation of this knowledge into routine clinical practice has been variable. It has become increasing clear that primary percutaneous coronary intervention (PCI) is the preferred method of reperfusion if it can be performed in a timely manner. Recent European data suggest that transfer for direct PCI may also be preferable to fibrinolytic therapy. We believe it is time to establish a national policy for treatment of patients with STEMI to develop a coordinated system of care similar to that of the level 1 trauma system.

The pre-hospital electrocardiogram and time to reperfusion in patients with acute myocardial infarction, 2000-2002: findings from the National Registry of Myocardial Infarction-4

OBJECTIVES

The aim of this study was to determine the use of pre-hospital electrocardiogram (ECG) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing reperfusion therapy, and evaluate the effect of pre-hospital ECG on door-to-reperfusion times.

BACKGROUND

Although national guidelines recommend the use of pre-hospital ECG, there is limited contemporary information about its current use and effectiveness.

METHODS

Using data from the National Registry of Myocardial Infarction-4, we studied patients with STEMI or left bundle branch block who received acute reperfusion with either fibrinolytic therapy (n = 35,370) or primary percutaneous coronary intervention (PCI) (n = 21,277) within 6 h of admission. We determined the prevalence of pre-hospital ECG use, evaluated the association between pre-hospital ECG and door-to-reperfusion time, and estimated the incremental reduction in time to reperfusion using hierarchical models to adjust for differences in patient and hospital characteristics.

RESULTS

A pre-hospital ECG was performed in 4.5% of the fibrinolytic therapy cohort and in 8.0% of the PCI cohort. After adjusting for patient and hospital characteristics, the use of pre-hospital ECG was associated with a significantly shorter geometric mean door-to-drug time: 24.6 min (95% confidence interval [CI]: 23.7 to 25.5) vs. 34.7 min (95% CI: 34.2 to 35.3; p < 0.0001), and a significantly shorter geometric mean door-to-balloon time (94.0 min [95% CI: 91.8 to 96.3] vs. 110.3 min [95% CI: 108.7 to 112.0]; p < 0.0001).

CONCLUSIONS

The national use of pre-hospital ECG to diagnose and facilitate the treatment of STEMI remains low. When used, however, pre-hospital ECG is associated with a significantly shorter time to reperfusion.

Initial approach to the patient who has chest pain

The last decade has seen extraordinary advances in the cardiovascular arena, particularly in the evaluation and management of the patient who has acute coronary syndromes. From bedside markers of myocardial damage to drug-eluting stents, technical advances are proliferating. Efforts in developing an international registry for acute aortic dissection have helped elucidate the acute presentation, management, and prognosis of this uncommon but lethal disease. Finally, the multiple research efforts in coordinating clinical decision-making with serologic markers and advanced imaging for the diagnosis of pulmonary embolism is changing the approach to the patient at risk for thromboembolic disease.

Driving Times and Distances to Hospitals With Percutaneous Coronary Intervention in the United States

Background— The success of prehospital triage protocols for patients with ST-elevation myocardial infarction (STEMI) will depend, in part, on how patients are geographically distributed around hospitals that perform percutaneous coronary intervention (PCI). Accordingly, we determined the proportion of the adult population in the United States with timely access to PCI hospitals using driving times and distances.

Methods and Results— We performed a cross-sectional study using hospital-level data from the American Hospital Association Annual Survey and Census tract-level data on adults 18 years of age or older from the 2000 United States Census. Our aims were to determine the proportion of the adult population who (1) lived within 60 minutes of a PCI hospital and (2) had additional transport times within 30 minutes if directly referred to a PCI hospital as opposed to a closer, non-PCI hospital. Median times and distances to the closest PCI hospital were 11.3 (interquartile range [IQR] 5.7 to 28.5) minutes and 7.9 (IQR 3.5 to 22.4) miles, respectively. A total of 79.0% of the adult population lived within 60 minutes of a PCI hospital. Among those with a non-PCI hospital as their closest facility, 74.0% required additional transport times of <30 minutes if directly referred to a PCI hospital as opposed to the non-PCI hospital. These estimates varied substantially across regions and urban, suburban, and rural Census tracts.

Conclusions— Nearly 80% of the adult population in the United States lived within 60 minutes of a PCI hospital in 2000. Even among those living closer to non-PCI hospitals, almost three fourths would experience <30 minutes of additional delay with direct referral to a PCI hospital, which suggests that such a strategy might be feasible for these individuals.

Comparison of mortality patterns in patients with ST-elevation myocardial infarction arriving by emergency medical services versus self-transport (from the prospective Ottawa Hospital STEMI Registry)

Emergency medical services (EMSs) play a key role in the recognition and treatment of ST-elevation of myocardial infarction (STEMI). We sought to determine contemporary use of EMS in patients with STEMI and its relation to treatment, morbidity, and mortality patterns. Patients who arrived by EMS were compared with those who arrived by self-transport. Among 401 patients, 59.9% arrived by EMS and 40.1% by self-transport. Patients who arrived by EMS were older (p <0.001) and had higher Killip's scores (p <0.001). Door-to-needle and door-to-balloon intervals were shorter in patients who arrived by EMS (42 vs 57 minutes, p <0.001, and 124 vs 154 minutes, p <0.001, respectively). In-hospital mortality was higher in patients who used EMS (13.3% vs 5.0%, p <0.001). Patients who arrived by EMS also had higher mortality within the first hour of hospital arrival (4.2% vs 0%, p = 0.007). Multivariate analysis showed that only age and systolic blood pressure were predictors of mortality. Despite faster onset of reperfusion therapy in patients who arrived by EMS, mortality was higher. Almost 33% of these deaths occurred in the early in-hospital period, which was due to older and sicker patients having the tendency to come by EMS. Our results suggest that regional approaches are needed to trigger earlier reperfusion therapy in patients with STEMI who use EMS.

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

Emergency medical services (EMS) providers who administer advanced life support should include diagnostic 12-lead electrocardiography programs as one of their services. Evidence demonstrates that this technology can be readily used by EMS providers to identify patients with ST-segment elevation myocardial infarction (STEMI) before a patient's arrival at a hospital emergency department. Earlier identification of STEMI patients leads to faster artery-opening treatment with fibrinolytic agents, either in the pre-hospital setting or at the hospital. Alternatively, a reperfusion strategy using percutaneous coronary intervention can be facilitated by use of pre-hospital 12-lead electrocardiography (P12ECG). Analysis of the cost of providing this service to the community must include consideration of the demonstrated benefits of more rapid treatment of patients with STEMI and the resulting time savings advantage shown to accompany the use of P12ECG programs.

Emergency Medical Service Aspects of Emergency Cardiac Care

Prehospital intervention has the potential for significantly affecting the outcome of cardiovascular emergencies. The authors examine multiple issues in prehospital care that can streamline and improve cardiac care. Improving access to prehospital care and increasing the use of the emergency medical services (EMS) system can speed interventions to the patients. The use of ECG in the out-of-hospital setting can reduce time to definitive treatment. Issues, such as the use of public access defibrillation and interfacility transports are also discussed.

Why do acute myocardial infarction patients not call an ambulance? An interview with patients presenting to hospital with acute myocardial infarction symptoms

BACKGROUND

Studies from overseas indicate that patients with acute myocardial infarction (AMI) symptoms often fail to use the emergency services as recommended, thereby depriving themselves from life-saving treatment in case of cardiac arrest and delaying the time to myocardial reperfusion in the presence of a coronary occlusion.

AIMS

To compare patients brought in by ambulance to those not brought in by ambulance and to question why some patients do not use the emergency services when presenting to hospital with AMI symptoms.

METHODS

Prospective interview and follow up of consecutive patients presenting with AMI symptoms to the emergency department of a tertiary hospital in a metropolitan area within a 1-month period.

RESULTS

Of the 215 patients presenting to the emergency department, 113 (53%) arrived by private transportation. Sixty (53%) of these felt their symptoms did not warrant calling the ambulance, 17 (15%) had first consulted their general practitioner. The private transport group accounted for 28% of documented AMI.

CONCLUSIONS

A large proportion of patients with AMI symptoms refrain from calling the emergency services because they do not consider themselves critically ill. Education programmes appear to be warranted because more appropriate use of emergency services will save lives.

Design of a standardized system for transfer of patients with ST-elevation myocardial infarction for percutaneous coronary intervention

BACKGROUND

Direct percutaneous coronary intervention (PCI) is the preferred method of reperfusion for ST-elevation myocardial infarction (STEMI). Transfer from community hospitals to PCI centers increases availability for direct PCI, which improves outcomes compared to fibrinolysis in Europe. It has been difficult to achieve similar door-to-balloon times for transfer patients in the United States.

METHODS

We designed a standardized protocol and integrated system of transfer for patients with STEMI. We report the door-to-balloon times for the pre- and postpilot patients in the index hospital and describe the details of the current Level 1 MI Program.

RESULTS

In the 15 months before the pilot project, the door-to-balloon time for patients receiving ad hoc transfer for direct PCI was 192 minutes, similar to the national average. The door-to-balloon time for the patients receiving rescue PCI after failed thrombolysis was 221 minutes. The standardized protocol decreased door-to-balloon time to 98 minutes in the pilot trial (P < .01) and has now been applied successfully in 29 community hospitals.

CONCLUSIONS

Rapid transfer of patients with STEMI is feasible in the United States using a standardized protocol and integrated transfer system. This requires a team approach with cooperation between cardiologists, emergency physicians, nurses, and the emergency medical system as well as various health care organizations.

The acute coronary syndrome--pre-hospital diagnostic quality

BACKGROUND AND OBJECTIVE

In the Austrian emergency medical service (EMS), emergency medical technician-staffed and physician-staffed vehicles are in operation. Patients with suspected acute coronary syndromes (ACS) are treated in the pre-hospital phase and transported to the hospital by an emergency physician (EP). This study evaluates the diagnostic performance of EPs in ACS and the impact of this emergency system on the outcome of ACS in an urban area.

DESIGN

Retrospective case control study.

METHODS

All protocol sheets from the emergency physicians were searched for the diagnosis of ACS. The database of the emergency department (ED) was searched for patients with ACS as an admission diagnosis or ACS as discharge diagnosis. For patients admitted to an intensive care unit (ICU), the medical history from the ICU was reviewed. According to the diagnosis and the aggressiveness of therapy, patients were divided in five categories of severity at each stage of care (pre-hospital category, ED category, ICU category).

RESULTS

A total of 3585 patients was analysed. Only 17.8% of the patients with ACS as the admission diagnosis and 20.3% of the patients with ACS as the discharge diagnosis were transported by an EP. 46.8% of the ACS diagnosis by EPs were confirmed in hospital. Patients transported by EPs showed a higher all-cause mortality in hospital (1.6% vs. 0.6%; p=0.011). There was no significant correlation between the pre-hospital category of patients treated by EPs and the ED category. When a 12-lead-electrocardiogram was recorded, the correlation improved slightly (rho: 0.139; p=0.006).

CONCLUSIONS

The percentage of ACS patients transported to hospital by an EP is very low, and EPs seem to be "over-aware" in the diagnosis of ACS.

Potential of an intracardiac electrogram for the rapid detection of coronary artery occlusion

BACKGROUND

Early identification of acute MI and prompt intervention can improve clinical outcomes. It would be valuable to identify a method that could allow the earliest possible detection of myocardial injury or ischemia.

METHODS AND RESULTS

This article reports one of the first clinical investigations to examine the ability of an intracardiac right ventricular (RV) electrode to identify the early onset of myocardial ischemia/injury in a cohort of patients undergoing balloon occlusion of a coronary artery during percutaneous transluminal coronary angioplasty. The primary data set for analysis included observations from 14 patients with 17 lesions, with a matched comparison of a V6 surface lead and the RV to left upper chest, "intracardiac" lead. The intracardiac lead was sensitive in detecting myocardial injury current/ischemia. There was a 36.4+/-5.6% ST-segment shift, relative to the amplitude of the QRS complex, in the intracardiac lead at 2 min, compared with a 10.1+/-1.9% ST shift from a surface lead (P=.00011). The RV to left upper chest lead detected a >10% shift in ST segment within 2 min in 17 (100%) of 17 cases vs. 8 (47%) of 17 for a V6 surface lead. The intracardiac lead provided detection of ischemia in all three major epicardial coronary distributions.

CONCLUSIONS

This study demonstrates the ability of an intracardiac (RV apex to left upper chest) lead to rapidly detect myocardial ischemia/injury during acute coronary occlusion in the setting of balloon angioplasty. The results of this study suggest that a simple implantable system resembling a ventricular pacemaker could be programmed to assist in the very early diagnosis of acute myocardial infarction.

Prehospital 80-LAD mapping: Does it add significantly to the diagnosis of acute coronary syndromes?

Early detection of acute myocardial infarction (MI) is vital in the management of acute coronary syndromes (ACS). Hence we compared the diagnostic capability of the standard 12-lead electrocardiogram (ECG) with the 80-lead ECG body surface map (BSM) prehospital.

METHODS

Consecutive patients (n = 294) presenting prehospital with ischemic type chest pain were included. All had an ECG and BSM pretreatment and a baseline and 12-hour cardiac troponin-T or I (cTnT or cTnI). Acute MI was defined as cTnT > 0.09 or cTnI > 0.1 ng/mL. Acute MI on the BSM was defined as ST elevation measured at the J-point, > or = 1 mm inferior/right ventricular/high right anterior/lateral regions, > or = 2 mm anterior region, > or = 0.5 mm posterior region.

RESULTS

Acute MI occurred in 182/294 (62%) based on cTnT or I. ST elevation on the standard ECG predicted acute MI in 103 (sensitivity 57%, specificity 94%; c-statistic 0.73). The optimal model for the standard ECG included ST elevation, summed ST depression and past history of MI (c-statistic 0.82; Chi-square (Wald) 120.7, 3df). The BSM predicted acute MI in 146 (sensitivity 80%, specificity 92%; c-statistic 0.86). The optimal model for the BSM included BSM criteria for acute MI and past history of MI (c-statistic 0.91; Chi-square (Wald) 180.3, 2df).

CONCLUSION

The 80-lead BSM is superior to the standard 12-lead ECG in predicting acute MI prehospital.