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Background: The objective of this study is to identify patient and EMS agency factors associated with timely reperfusion of patients with ST-elevation myocardial infarction (STEMI)., Methods: We conducted a cohort study of adult patients (≥18 years old) with STEMI activations from 2016 to 2020. Data was obtained from a regional STEMI registry, which included eight rural county EMS agencies and three North Carolina percutaneous coronary intervention (PCI) centers. On each patient, prehospital and in-hospital time intervals were abstracted. The primary outcome was the ability to achieve the 90-minute EMS FMC to PCI time goal (yes vs. no). We used generalized estimating equations accounting for within-agency clustering to evaluate the association between patient and agency factors and meeting first medical contact (FMC) to PCI time goal while accounting for clustering within the agency., Results: Among 365 rural STEMI patients 30.1% were female (110/365) with a mean age of 62.5 ± 12.7 years. PCI was performed within the time goal in 60.5% (221/365) of encounters. The FMC to PCI time goal was met in 45.5% (50/110) of women vs 69.8% (178/255) of men ( p  < 0.001). The median PCI center activation time was 12 min (IQR 7-19) in the group that received PCI within the time goal compared to 21 min (IQR 10-37) in the cohort that did not. After adjusting for loaded mileage and other clinical variables (e.g., pulse rate, hypertension etc.), the male sex was associated with an improved chance of meeting the goal of FMC to PCI (aOR: 2.94; 95% CI 2.11-4.10) compared to the female sex., Conclusion: Nearly 40% of rural STEMI patients transported by EMS failed to receive FMC to PCI within 90 min. Women were less likely than men to receive reperfusion within the time goal, which represents an important health care disparity.

Background: Emergency medical services (EMS) clinicians demonstrate a high prevalence of chronic medical conditions that place them at risk for early mortality. Workplace health promotion programs improve health outcomes, but the availably of such programs for EMS clinicians has not been described. We investigate the availability, scope, and participation of workplace health promotion programs available to EMS clinicians in North Carolina (NC)., Methods: We administered an electronic survey based on the Centers for Disease Control and Prevention Worksite Health ScoreCard to key representatives of EMS agencies within NC that provide primarily transport-capable 9-1-1 response with ground ambulances. We collected information on agency size, rurality, elements of health promotion programs offered, incentives for participation, and participation rate. We calculated descriptive statistics using frequency and percentage for worksite and health promotion program characteristics. We compared the participation rate for agencies who did and did not incentivize participation using Fisher's exact test., Results: Complete responses were received from 69 of 92 agencies (response = 75%) that collectively employ 6679 EMS clinicians [median employees per agency 71 (IQR 50-131)]. Most agencies (88.4%, 61/69) offered at least one element of a worksite health program, but only 13.0% (9/69) offered all elements of a worksite health program. In descending order, the availability of program elements were employee assistance programs (73.9%, 51/69), supportive physical and social environment (66.7%, 46/69), health education (62.3%, 43/69), health risk assessments (52.2%, 36/69), and organization culture of health promotion (20.3%, 14/69). Of agencies with programs, few (11.5%, 7/61) required participation, but most (59.0%, 36/61) offered incentives to participate. Participation rates were <25% among nearly all of the agencies that did not offer incentives, but >50% among most agencies that did offer incentives ( p  < 0.001)., Conclusion: While most agencies offer at least one element of a worksite health promotion program, few agencies offer all elements and participation rates are low.

Objective: The History, Electrocardiogram (ECG), Age, and Risk factor (HEAR) and History and ECG-only Manchester Acute Coronary Syndromes (HE-MACS) risk scores can risk stratify chest pain patients without troponin measures. The objective of this study was to determine if either risk score could achieve the ≥99% negative predictive value (NPV) required to rule out major adverse cardiovascular events (MACE; a composite of all-cause death, myocardial infarction, or coronary revascularization) at 30 days or the ≥50% positive predictive value (PPV) indicative of a patient possibly needing interventional cardiology., Methods: We performed a pre-planned secondary analysis of the prospective multisite PARAHEART ( n  = 462, 12/2016-1/2018) and RESCUE ( n  = 767, 4/2018-1/2019) trials, which accrued adults ≥21 years old with acute non-traumatic chest pain transported by emergency medical services (EMS). Paramedics prospectively completed risk assessment forms. Very low risk was defined by a HEAR score of 0-1 or HE-MACS probability <4%. The primary outcome was 30-day MACE, which was determined by adjudication (PARAHEART) or electronic record review (RESCUE). NPV and PPV with exact 95% confidence intervals (95%CI) for 30-day MACE were calculated for each risk score and compared using McNemar's tests., Results: Among the PARAHEART and RESCUE cohorts, 30-day MACE occurred in 18.8% (87/462) and 6.9% (53/767) of patients, respectively. In PARAHEART, 7.8% (36/462) were very low risk by HEAR score vs. 7.8% (36/462) by HE-MACS ( p  = 1.0). The HEAR score had a NPV of 97.2% (95%CI 91.9-100.0) vs. 91.7% (95%CI 82.6-100.0) for HE-MACS ( p  = 0.15). The HEAR and HE-MACS PPVs were similar [46.4% (95%CI 28.0-64.9) vs. 33.3% (95%CI 13.2-53.5) ( p  = 0.26)]. In RESCUE, the HEAR score identified 14.2% (109/767) as low risk compared to 8.3% (64/767) by HE-MACS ( p  < 0.001). In this cohort, the HEAR and HE-MACS scores had similar NPVs [98.2% (95%CI 95.7-100.0) vs. 98.4% (95%CI 95.4-100.0) ( p  = 0.89)] and PPVs [16.2% (95%CI 6.2-32.0) vs. 22.6% (95%CI 12.3-36.2) ( p  = 0.41)]., Conclusions: In two prehospital chest pain cohorts, neither the HEAR score nor HE-MACS achieved sufficient NPV or PPV to rule out or rule in 30-day MACE.

Background: ST-elevation myocardial infarction (STEMI) guidelines recommend an emergency medical services (EMS) first medical contact (FMC) to percutaneous coronary intervention (PCI) time of ≤90 min. The primary objective of this study was to evaluate the association between FMC to PCI time and mortality in rural STEMI patients., Methods: We conducted a cohort study of patients ≥18 years old with STEMI activations from January 2016 to March 2020. Data were obtained from a rural North Carolina Regional STEMI Data Registry, which included eight rural EMS agencies and three PCI centers, the National Cardiovascular Data Registry, and the EMS electronic health record. Prehospital and in-hospital time intervals were digitally abstracted. The outcome of index hospitalization mortality was compared between patients who did and did not meet FMC to PCI time goal using Fisher's exact tests. Negative predictive value (NPV) for index hospitalization death was calculated with 95% confidence intervals (CIs). A receiver operating characteristic curve was constructed and an optimal FMC to PCI time goal was identified by maximizing NPV to prevent index hospitalization death., Results: Among 365 rural EMS STEMI patients, 30.1% (110/365) were female with a mean ± SD age of 62.5 ± 12.7 years. PCI was performed within the 90-min time goal in 60.5% (221/365) of patients. Among these patients, 3% (11/365) died during initial STEMI hospitalization, with 1.4% (3/221) mortality in the group that met the 90-minute time goal compared to 5.6% (8/144) in patients exceeding the time goal (p = 0.03). Meeting the 90-min time goal yielded a 98.6% (95% CI 96.1%-99.7%) NPV for index death. A 78-min FMC to PCI time was the optimal cut point, yielding a NPV for index mortality of 99.3% (95% CI 96.1%-100%)., Conclusions: Death among rural patients with STEMI was four times more likely when they did not receive PCI within 90 min., (© 2023 The Authors. Academic Emergency Medicine published by Wiley Periodicals LLC on behalf of Society for Academic Emergency Medicine.)

Background: Metabolic syndrome is a constellation of risk factors associated with the development of cardiovascular disease and increased all-cause mortality. Data examining the prevalence of metabolic syndrome among emergency medical services (EMS) clinicians are limited., Methods: We conducted a cross-sectional study of EMS clinicians and firefighters from three fire departments with transport-capable EMS divisions. Data were collected from compulsory annual physical exams for 2021 that included age, sex, race, body mass index (BMI), waist circumference, blood pressure, cholesterol levels, and hemoglobin A1c level. These data were used to determine the prevalence of meeting metabolic syndrome criteria. We calculated descriptive statistics of demographics, anthropometrics, and metabolic syndrome criteria for EMS clinicians and firefighters. We used chi-square tests to compare the proportion of EMS clinicians and firefighters meeting criteria for the whole group and among age groups of <40 years old, 40 to 59 years old, and ≥60 years old. We used logistic regression to estimate the odds of meeting criteria in EMS clinicians compared to firefighters, adjusted for age, sex, race, and BMI., Results: We reviewed data for 65 EMS clinicians and 239 firefighters. For the combined cohort, 13.2% (40/304) were female and 95.1% (289/304) were White. The median age for EMS clinicians was 34 years versus 45 years in firefighters (p < 0.0001). Metabolic syndrome criteria were met in 27.3% (83/304) of the entire group. The prevalence of meeting criteria among EMS clinicians and firefighters was 33.9% (22/65) and 25.5% (61/239), respectively (p = 0.18). Of the participants who were younger than age 40, 36.6% (15/41) of EMS clinicians versus 9.1% (7/74) of firefighters met criteria for metabolic syndrome (p < 0.001). EMS clinicians had significantly higher odds of meeting criteria [OR 4.62 (p = 0.001)] compared to firefighters when adjusted for age, sex, race, and BMI., Conclusion: EMS clinicians had a high prevalence of metabolic syndrome at an early age, and had a higher adjusted odds of having metabolic syndrome compared to firefighters.

Background: Rural patients with ST-elevation myocardial infarction (STEMI) may be less likely to receive prompt reperfusion therapy. This study's primary objective was to compare rural versus urban time intervals among a national cohort of prehospital patients with STEMI., Methods: The ESO Data Collaborative (Austin, TX), containing records from 1,366 emergency medical services agencies, was queried for adult 9-1-1 responses with suspected STEMI from 1/1/2018-12/31/2019. The scene address for each encounter was classified as either urban or rural using the 2010 US Census Urban Area Zip Code Tabulation Area relationship. The primary outcome was total EMS interval (9-1-1 call to hospital arrival); a key secondary outcome was the proportion of responses that had EMS intervals under 60 minutes. Generalized estimating equations were used to determine whether rural versus urban differences in interval outcomes occurred when adjusting for loaded mileage (distance from scene to hospital) and patient and clinical encounter characteristics., Results: Of 15,915,027 adult 9-1-1 transports, 23,655 records with suspected STEMI were included in the analysis. Most responses (91.6%, n = 21,661) occurred in urban settings. Median EMS interval was 37.6 minutes (IQR 30.0-48.0) in urban settings compared to 57.0 minutes (IQR 46.5-70.7) in rural settings (p < 0.01). Urban responses more frequently had EMS intervals <60 minutes (89.5%, n = 19,130), compared to rural responses (55.5%, n = 1,100, p < 0.01). After adjusting for loaded mileage, age, sex, race/ethnicity, abnormal vital signs, pain assessment, aspirin administration, and IV/IO attempt, rural location was associated with a 5.8 (95%CI 4.2-7.4) minute longer EMS interval than urban, and rural location was associated with a reduced chance of achieving EMS interval < 60 minutes (OR 0.40; 95%CI 0.33-0.49) as compared to urban location., Conclusion: In this large national sample, rural location was associated with significantly longer EMS interval for patients with suspected STEMI, even after accounting for loaded mileage.

Background: Cardiac arrest guidelines recommend epinephrine every 3-5 minutes during cardiac arrest resuscitation. However, it is unclear if multiple epinephrine doses are associated with improved outcomes. The objective of this study was to determine if a single-dose epinephrine protocol was associated with improved survival compared to traditional multidose protocols., Methods: We conducted a pre-post study across five North Carolina EMS agencies from 11/1/2016 to 10/29/2019. Patients ≥18 years old with attempted resuscitation for non-traumatic prehospital cardiac arrest were included. Data were collected 1 year before and after implementation of the single-dose epinephrine protocol. Prior to implementation, all agencies used a multidose epinephrine protocol. The Cardiac Arrest Registry to Enhance Survival (CARES) was used to obtain patient outcomes. Study outcomes were survival to hospital discharge (primary) and return of spontaneous circulation (ROSC). Analysis was by intention to treat. Outcomes were compared pre- vs. post-implementation using generalized estimating equations to account for clustering within EMS agencies. Adjusted analyses included age, sex, race, shockable vs. non-shockable rhythm, witnessed arrest, automatic external defibrillator availability, EMS response interval, and bystander cardiopulmonary resuscitation., Results: During the study period there were 1,690 encounters (899 pre- and 791 post-implementation). The population was 74.7% white, 61.1% male, and had a median age of 65 (IQR 53-76) years. Survival to hospital discharge was similar pre- vs. post-implementation [13.6% (122/899) vs. 15.4% (122/791); OR 1.19, 95%CI 0.89-1.59]. However, ROSC was more common post-implementation [42.3% (380/899) vs. 32.5% (257/791); OR 0.66, 95%CI 0.54-0.81]. After adjusting for covariates, the single-dose protocol was associated with similar survival to discharge rates (aOR 0.88, 95%CI 0.77-1.29), but with decreased ROSC rates (aOR 0.58, 95%CI 0.47-0.72)., Conclusion: A prehospital single-dose epinephrine protocol was associated with similar survival to hospital discharge, but decreased ROSC rates compared to the traditional multidose epinephrine protocol.

Background: Emergency medical services (EMS) assesses millions of patients with chest pain each year. However, tools validated to risk stratify patients for acute coronary syndrome (ACS) and pulmonary embolism (PE) have not been translated to the prehospital setting. The objective of this study is to assess the prehospital performance of risk stratification scores for 30-day major adverse cardiac events (MACE) and PE., Methods: A prospective observational cohort study of patients ≥21 years of age with acute chest pain who were transported by EMS in two North Carolina (NC) counties was conducted from 18 April 2018-2 January 2019. In this convenience sample, paramedics completed HEAR (history, electrocardiogram, age, risk factor), ED Assessment of Chest Pain Score (EDACS), Revised Geneva Score (RGS), and pulmonary embolism rule-out criteria (PERC) assessments on each patient. MACE (all-cause death, myocardial infarction, and revascularization) and PE at 30 days were determined by hospital records and NC Death Index. The positive (+LR) and negative likelihood ratios (-LR) of the risk scores for 30-day MACE and PE were calculated., Results: During the study period, 82.1% (687/837) patients had all four risk score assessments. The cohort was 51.1% (351/687) female, 49.5% (340/687) African American, and had a mean age of 55.0 years (SD 16.0). At 30 days, MACE occurred in 7.4% (51/687), PE occurred in 0.9% (6/687), and the combined outcome occurred in 8.2% (56/687). The HEAR score had a - LR of 0.46 (95% CI 0.27-0.78) and + LR of 1.48 (95% CI 1.26-1.74) for 30-day MACE. EDACS had a - LR of 0.61 (95% CI 0.46-0.81) and + LR of 2.53 (95% CI 1.86-3.46) for 30-day MACE. The PERC score had a - LR of 0 (95% CI 0.0-1.4) and a + LR of 1.38 (95% CI 1.32-1.45) for 30-day PE. The RGS score had a - LR of 0 (95% CI 0.0-0.65) and a + LR of 2.36 (95% CI 2.16-2.57) for 30-day PE. The combination of a low-risk HEAR score and negative PERC evaluation had a - LR of 0.25 (95% CI 0.08-0.76) and a + LR of 1.21 (95% CI 1.21-1.30) for 30-day MACE or PE., Conclusion: The combination of a paramedic-obtained HEAR score and PERC evaluation performed best to exclude 30-day MACE and PE but was not sufficient for directing prehospital decision making.

Objective: Delays in care for patients with acute cardiac complaints are associated with increased morbidity and mortality. The objective of this study was to quantify rural and urban differences in prehospital time intervals for patients with cardiac complaints., Methods: The ESO Data Collaborative dataset consisting of records from 1332 EMS agencies was queried for 9-1-1 encounters with acute cardiac problems among adults (age ≥ 18) from 1/1/2013-6/1/2018. Location was classified as rural or urban using the 2010 United States Census. The primary outcome was total prehospital time. Generalized estimating equations evaluated differences in the average times between rural and urban encounters while controlling for age, sex, race, transport mode, loaded mileage, and patient stability., Results: Among 428,054 encounters, the median age was 62 (IQR 50-75) years with 50.7% female, 75.3% white, and 10.3% rural. The median total prehospital, response, scene, and transport times were 37.0 (IQR 29.0-48.0), 6.0 (IQR 4.0-9.0), 16.0 (IQR 12.0-21.0), and 13.0 (IQR 8.0-21.0) minutes. Rural patients had an average total prehospital time that was 16.76 min (95%CI 15.15-18.38) longer than urban patients. After adjusting for covariates, average total time was 5.08 (95%CI 4.37-5.78) minutes longer for rural patients. Average response and transport time were 4.36 (95%CI 3.83-4.89) and 0.62 (95%CI 0.33-0.90) minutes longer for rural patients. Scene time was similar in rural and urban patients (0.09 min, 95%CI -0.15-0.33)., Conclusion: Rural patients with acute cardiac complaints experienced longer prehospital time than urban patients, even after accounting for other key variables, such as loaded mileage., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Introduction: Chest pain is a common reason for ambulance transport. Acute coronary syndrome (ACS) and pulmonary embolism (PE) risk assessments, such as history, electrocardiogram, age, risk factors (HEAR); Emergency Department Assessment of Chest Pain Score (EDACS); Pulmonary Embolism Rule-out Criteria (PERC); and revised Geneva score, are well validated for emergency department (ED) use but have not been translated to the prehospital setting. The objectives of this study were to evaluate the 1) prehospital completion rate and 2) inter-rater reliability of chest pain risk assessments., Methods: We conducted a prospective observational cohort study in two emergency medical services (EMS) agencies (April 18, 2018 - January 2, 2019). Adults with acute, non-traumatic chest pain without ST-elevation myocardial infarction or unstable vital signs were accrued. Paramedics were trained to use the HEAR, EDACS, PERC, and revised Geneva score assessments. A subset of patients (a priori goal of N = 250) also had the four risk assessments completed by their treating clinicians in the ED, who were blinded to the EMS risk assessments. Outcomes were 1) risk assessments completion rate and 2) inter-rater reliability between EMS and ED assessments. An a priori goal for completion rate was set as >75%. We computed kappa with corresponding 95% confidence intervals (CI) for each risk assessment as a measure of inter-rater reliability. Acceptable agreement was defined a priori as kappa ≥ 0.60., Results: During the study period, 837 patients with acute chest pain were accrued. The median age was 54 years, interquartile range 43-66, with 53% female and 51% Black. Completion rates for each risk assessment were above goal: the HEAR score was completed on 95.1% (796/837), EDACS on 92.0% (770/837), PERC on 89.4% (748/837), and revised Geneva score on 90.7% (759/837) of patients. We assessed agreement in a subgroup of 260 patients. The HEAR score had a kappa of 0.51 (95% CI, 0.41-0.61); EDACS was 0.60 (95% CI, 0.49-0.72); PERC was 0.71 (95% CI, 0.61-0.81); and revised Geneva score was 0.51 (95% CI, 0.39-0.62)., Conclusion: The completion rate of risk assessments for ACS and PE was high for prehospital field personnel. The PERC and EDACS both demonstrated acceptable agreement between paramedics and clinicians in the ED, although assessments with better agreement are likely needed.

Background: Expediting the measurement of serum troponin by leveraging EMS blood collection could reduce the diagnostic time for patients with acute chest pain and help address Emergency Department (ED) overcrowding. However, this practice has not been examined among an ED chest pain patient population in the United States., Methods: A prospective observational cohort study of adults with non-traumatic chest pain without ST-segment elevation myocardial infarction was conducted in three EMS agencies between 12/2016-4/2018. During transport, paramedics obtained a patient blood sample that was sent directly to the hospital core lab for troponin measurement. On ED arrival HEART Pathway assessments were completed by ED providers as part of standard care. ED providers were blinded to troponin results from EMS blood samples. To evaluate the potential impact on length of stay (LOS), the time difference between EMS blood draw and first clinical ED draw was calculated. To determine the safety of using troponin measures from EMS blood samples, the diagnostic performance of the HEART Pathway for 30-day major adverse cardiac events (MACE: composite of cardiac death, myocardial infarction (MI), coronary revascularization) was determined using EMS troponin plus arrival ED troponin and EMS troponin plus a serial 3-h ED troponin., Results: The use of EMS blood samples for troponin measures among 401 patients presenting with acute chest pain resulted in a mean potential reduction in LOS of 72.5 ± SD 35.7 min. MACE at 30 days occurred in 21.0% (84/401), with 1 cardiac death, 78 MIs, and 5 revascularizations without MI. Use of the HEART Pathway with EMS and ED arrival troponin measures yielded a NPV of 98.0% (95% CI: 89.6-100). NPV improved to 100% (95% CI: 92.9-100) when using the EMS and 3-h ED troponin measures., Conclusions: EMS blood collection used for core lab ED troponin measures could significantly reduce ED LOS and appears safe when integrated into the HEART Pathway., Competing Interests: Declaration of Competing Interest Dr. Stopyra receives research funding from NCATS/NIH (KL2TR001421), HRSA (H2ARH39976-01-00), NHLBI (U01HL123027), Roche Diagnostics and Abbott Point of Care. He has provided paid consulting to Roche Diagnostics. Dr. Snavely receives research funding from NHLBI (1 R01 HL118263-01) and HRSA (1 H2ARH399760100). Dr. Miller receives research funding/support from Siemens, Abbott Point of Care, Creavo Medical Technologies, Marcus Foundation, RTI International, Grifols, and NHLBI1 R01 HL118263. Dr. Mahler receives research funding from the Donaghue Foundation, Abbott Laboratories, Roche Diagnostics, Siemens, Ortho Clinical Diagnostics, Creavo Medical Technologies, PCORI, AHRQ, NHLBI (1 R01 HL118263-01) and HRSA (1 H2ARH399760100). He was a paid consultant for Roche Diagnostics and Amgen. Dr. Mahler is the Chief Medical Officer for Impathiq Inc., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Use of point-of-care (POC) troponin (cTn) testing in the Emergency Department (ED) is well established. However, data examining POC cTn measurement in the prehospital setting, during ambulance transport, are limited. The objective of this study was to prospectively test the performance of POC cTn measurement by paramedics to detect myocardial infarction (MI) among patients transported to the ED for acute chest pain. Methods: A prospective cohort study of adults with non-traumatic chest pain was conducted in three Emergency Medical Services agencies (December 2016 to January 2018). Patients with ST-elevation MI on ECG were excluded. During ambulance transport paramedics initiated intravenous access, collected blood, and used a POC device (i-STAT; Abbott Laboratories) to measure cTn. Following ED arrival, participants received standard evaluations including clinical blood draws for cTn measurement in the hospital central lab (AccuTnI +3 assay; Beckman Coulter, or cTnI-Ultra assay; Siemens). Blood collected during ambulance transport was also analyzed for cTn in the central lab. Index visit MI was adjudicated by 3 experts using central lab cTn measures from the patient's clinical blood draws. Test characteristics (sensitivity, specificity, and predictive values) for detection of MI were calculated for POC and central lab cTn measurement of prehospital blood and compared with McNemar's test. Results: During the study period prehospital POC cTn results were obtained on 421 patients, of which 5.0% (21/421) had results >99th percentile upper reference limit. MI was adjudicated in 16.2% (68/421) during the index visit. The specificity and positive predictive value of the POC cTn measurement were 99.2% (95% CI 97.5-99.8%) and 85.7% (95% CI 63.7-97.0%) for MI. However, the sensitivity and NPV of prehospital POC cTn were 26.5% (95% CI 16.5-38.6%) and 87.5% (95% CI 83.9-90.6%). Compared to POC cTn, the central lab cTn measurement of prehospital blood resulted in a higher sensitivity of 67.9% (95% CI 53.7-80.1%, p  < 0.0001), but lower specificity of 92.4% (95% CI 88.4-95.4%, p  = 0.0001). Conclusions: Prehospital POC i-STAT cTn measurement in patients transported with acute chest pain was highly specific for MI but had low sensitivity. This suggests that prehospital i-STAT POC cTn could be useful to rule-in MI, but should not be used to exclude MI.

Introduction The History, Electrocardiogram (ECG), Age, Risk Factors, and Troponin (HEART) score is a decision aid designed to risk stratify emergency department (ED) patients with acute chest pain. It has been validated for ED use, but it has yet to be evaluated in a prehospital setting. Hypothesis A prehospital modified HEART score can predict major adverse cardiac events (MACE) among undifferentiated chest pain patients transported to the ED., Methods: A retrospective cohort study of patients with chest pain transported by two county-based Emergency Medical Service (EMS) agencies to a tertiary care center was conducted. Adults without ST-elevation myocardial infarction (STEMI) were included. Inter-facility transfers and those without a prehospital 12-lead ECG or an ED troponin measurement were excluded. Modified HEART scores were calculated by study investigators using a standardized data collection tool for each patient. All MACE (death, myocardial infarction [MI], or coronary revascularization) were determined by record review at 30 days. The sensitivity and negative predictive values (NPVs) for MACE at 30 days were calculated., Results: Over the study period, 794 patients met inclusion criteria. A MACE at 30 days was present in 10.7% (85/794) of patients with 12 deaths (1.5%), 66 MIs (8.3%), and 12 coronary revascularizations without MI (1.5%). The modified HEART score identified 33.2% (264/794) of patients as low risk. Among low-risk patients, 1.9% (5/264) had MACE (two MIs and three revascularizations without MI). The sensitivity and NPV for 30-day MACE was 94.1% (95% CI, 86.8-98.1) and 98.1% (95% CI, 95.6-99.4), respectively., Conclusions: Prehospital modified HEART scores have a high NPV for MACE at 30 days. A study in which prehospital providers prospectively apply this decision aid is warranted. Stopyra JP , Harper WS , Higgins TJ , Prokesova JV , Winslow JE , Nelson RD , Alson RL , Davis CA , Russell GB , Miller CD , Mahler SA . Prehospital modified HEART score predictive of 30-day adverse cardiac events. Prehosp Disaster Med. 2018;33(1):58-62.