Use of prehospital 12-lead electrocardiography and treatment times among ST-elevation myocardial infarction patients with atypical symptoms

A Qualitative Analysis of Barriers to Evidence-Based Care in the Prehospital Management of Patients with Suspected Acute Coronary Syndrome

OBJECTIVES

Prehospital electrocardiogram (ECG) and administration of aspirin are evidence-based strategies for patients with acute coronary syndrome (ACS). However, emergency medical services (EMS) compliance in patients with suspected ACS varies widely. We sought to understand the barriers to prehospital ECG acquisition and aspirin administration for patients with suspected ACS.

METHODS

In this qualitative study, we interviewed EMS clinicians at three geographically diverse United States (U.S.)-based EMS agencies. We interviewed practicing clinicians and quality and operations leaders at these agencies. Based on the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework, interviews were recorded, transcribed, and analyzed using a grounded qualitative approach with open coding. The Systems Engineering Initiative for Patient Safety (SEIPS) framework and a constant comparison technique were used to identify and refine themes.

RESULTS

Twenty-five paramedics and 20 additional agency personnel participated. Median age was 41 (IQR: 34-51) years and 13 (29%) were female. Themes were organized using SEIPS and longitudinally through four phases of an EMS call. During the pre-arrival phase, staffing challenges, training quality, and dispatch may anchor EMS clinicians on a diagnosis. During the diagnosis and treatment phase, safety and communication barriers may take priority over care delivery. Additionally, EMS clinicians must allocate assets (e.g. whether to send an advanced life support unit) and financial resources; veteran EMS clinicians identified their experience whereas newer clinicians cited their recent education when making these decisions. Also, diagnostic uncertainty due to increasing patient complexity and atypical presentations contributed to diagnostic errors. During the response and transport phase, the scope of practice limits the use and interpretation of the ECG, with clinicians reporting that liberal use of ECG led to more rapid decision-making. Finally, in the after phase, personnel reported the "psychologically taxing" nature of the job contributing to biases, bad habits, and burnout. Performance feedback was desired for personal development, though currently perceived as infrequent and punitive.

CONCLUSIONS

Multiple, interrelated themes underscored the complexities of delivering evidence-based care to prehospital patients with ACS. Education in ECG interpretation, resource allocation, bias, and enhancing feedback may serve as strategies to address the identified barriers.

Patient characteristics and outcomes of acute myocardial infarction presenting without ischemic pain: Insights from the Atherosclerosis Risk in Communities Study

Background

Our objective was to describe characteristics of patients presenting with and without ischemic pain among those diagnosed with acute myocardial infarction (MI) using individual-level data from the Atherosclerosis Risk in Communities Study from 2005 to 2019.

Methods

Acute MI included events deemed definite or probable MI by a physician panel based on ischemic pain, cardiac biomarkers, and ECG evidence. Patient characteristics included age at hospitalization, sex, race/ethnicity, comorbidities (smoking status, diabetes, hypertension, history of previous stroke, MI, or cardiovascular procedure, and history of valvular disease or cardiomyopathy) and in-hospital complications occurring during the event of interest (pulmonary edema, pulmonary embolism, in-hospital stroke, pneumonia, cardiogenic shock, ventricular fibrillation). Analyses were stratified by MI subtype (STEMI, NSTEMI, Unclassified) and patient characteristics and 28-day case fatality was compared between MI presenting with or without ischemic pain.

Results

Between 2005 and 2019, there were 1711 hospitalized definite/probable MI events (47 % female, 26 % black, and age of 78 [6.7 years]). A smaller proportion of STEMI patients presented without ischemic pain compared to NSTEMI patients (20 % vs 32 %). Race, sex, age, and comorbidity profiles did not differ significantly across ischemic pain presentations. Patients presenting without ischemic pain had a higher 28-day all-cause case fatality after adjusting for age, race, sex, and comorbidities. However, after further adjustment, time from symptom onset to hospital arrival, time to treatment, and in-hospital complications explained the difference in 28-day case fatality between ischemic pain presentations.

Conclusions

Future research should focus on differences in treatment delay across ischemic pain presentations rather than sex differences in acute coronary syndrome presentation.

Identification of Acute Coronary Syndrome in the Elderly

When older adults experience acute coronary syndrome (ACS), they often present with what are considered "atypical" symptoms. Because their symptoms less often match the expected presentation of ACS, older patients can have delayed time to assessment, to performance of an electrocardiogram, to diagnosis, and to definitive management. Unfortunately, it is this very group of patients who are at the highest risk for having ACS and for complications from ACS. This article aims to outline presentation, outcomes, and potential solutions of underrecognition of ACS in the older adult population.

Characteristics of Prehospital Electrocardiogram Use in North Carolina Using a Novel Linkage of Emergency Medical Services and Emergency Department Data

Objective: Prehospital electrocardiography (ECG) is recommended for patients with suspected acute coronary syndrome (ACS), yet only 20-80% of chest pain patients receive a prehospital ECG. Less is known about prehospital ECG use in patients with less common complaints (e.g., fatigue) suspicious for ACS who are transported by emergency medical services (EMS). The aims of this study were to determine: (1) the proportion of patients with chest pain and less typical complaints, and (2) patient characteristics associated with prehospital ECG use in patients transported by EMS to emergency departments across North Carolina. Methods: A novel linked database was created between prehospital and emergency department (ED) patient care data from the North Carolina Prehospital Medical Information System and the North Carolina Disease Event Tracking and Epidemiologic Collection Tool. Institutional review board approval and a data use agreement were received prior to the start of the study. Patients ≥21 transported during 2010-14 by EMS with select variables were included. We examined patients' complaints (symptoms), characteristics (e.g., race, ethnicity, final hospital diagnosis), and prehospital ECG use (yes/no). Analysis included descriptive statistics and mixed logistic regression. Results: During 2010-14, there were 1,967,542 patients with linked EMS-ED data (mean age: 56.9 [SD: 22.2], 43.2% male, 63.7% White). Of these, 643,174 (32.6%) received a prehospital ECG. Patients with prehospital ECG presented with the following complaints: 20% chest pain; 10% shortness of breath; 6% abdominal pain/problems; 6% altered level of consciousness; 5% syncope/dizziness; 4% palpitations; 12% other complaints; and 37% missing. Patients' presenting complaints were the strongest predictor of prehospital ECG use, adjusting for age, sex, race, ethnicity, urbanicity, and date and time of EMS dispatch. Conclusions: Patients with chest pain were significantly more likely to receive a prehospital ECG compared to those with less typical but suspicious complaints for ACS. Patients with less common presentations remain disadvantaged for early triage, risk stratification, and intervention prior to the hospital.

Implementation of an ST-Segment Elevation Myocardial Infarction Bypass Protocol in the Northern United Arab Emirates

Objective:

The aim was to evaluate the translation of an ST-segment elevation myocardial infarction (STEMI) bypass protocol to the outcomes of patients with acute coronary syndrome in the Emirate of Ras al-Khaimah in the United Arab Emirates (UAE).

Methods:

A prospective cohort study was conducted, which included all patients who had a prehospital 12-lead electrocardiogram (ECG) performed by ambulance crews. Analysis of those who were identified as having STEMI and who subsequently underwent percutaneous coronary intervention (PCI) was performed.

Results:

A total of 152 patients had a 12-lead ECG performed during the pilot study period (February 24, 2016–August 31, 2016) with 118 included for analysis. Mean patient age was 52 years. There were 87 male (74%) and 31 female (26%) patients. Twenty-nine patients suffered a STEMI, and data were available for 11 who underwent PCI. There was no mortality, and no major adverse cardiac events were reported. The median door-to-balloon (D2B) time was 73 min (range 48–124), and 81% of patients had a D2B time < 90 min. Discharge data were available for six patients: All were discharged home with no impediments to rehabilitation.

Conclusion:

This pilot study has demonstrated agreement with the existing literature surrounding prehospital ECG and PCI activation in an unstudied STEMI population and in a novel clinical setting. It has demonstrated a D2B time of < 90 min in over 80% of STEMI patients, and a faster mean D2B time than self-presentations (mean 77 min vs. 113 min), with no associated mortality or major adverse cardiac events.

Characterization and referral patterns of ST-elevation myocardial infarction patients admitted to chest pain units rather than directly to catherization laboratories. Data from the German Chest Pain Unit Registry

BACKGROUND

Direct transfer to the catheterization laboratory for primary percutaneous coronary intervention (PCI) is standard of care for patients with ST-segment elevation myocardial infarction (STEMI). Nevertheless, a significant number of STEMI-patients are initially treated in chest pain units (CPUs) of admitting hospitals. Thus, it is important to characterize these patients and to define why an important deviation from recommended clinical pathways occurs and in particular to quantify the impact of deviation on critical time intervals.

METHODS AND RESULTS

1679 STEMI patients admitted to a CPU in the period from 2010 to 2015 were enrolled in the German CPU registry (8.5% of 19,666). 55.9% of the patients were delivered by an emergency medical system (EMS), 16.1% transferred from other hospitals and 15.2% referred by a general practitioner (GP). 12.7% were self-referrals. 55% did not get a pre-hospital ECG. Compared to the EMS, referral by GPs markedly delayed critical time intervals while a pre-hospital ECG demonstrating ST-segment elevation reduced door-to-balloon time. When compared to STEMI patients (n=21,674) enrolled in the ALKK-registry, CPU-STEMI patients had a lower risk profile, their treatment in the CPU was guideline-conform and in-hospital mortality was low (1.5%).

CONCLUSIONS

CPU-STEMI patients represent a numerically significant group because a pre-hospital ECG was not documented. Treatment in the CPU is guideline-conform and the intra-hospital mortality is low. The lack of a pre-hospital ECG and admission via the GP substantially delay critical time intervals suggesting that in patients with symptoms suggestive an ACS, the EMS should be contacted and not the GP.

Predictive value of routine point-of-care cardiac troponin T measurement for prehospital diagnosis and risk-stratification in patients with suspected acute myocardial infarction

OBJECTIVE

The purpose of this study was to determine the predictive value of routine prehospital point-of-care cardiac troponin T measurement for diagnosis and risk stratification of patients with suspected acute myocardial infarction.

METHODS AND RESULTS

All prehospital emergency medical service vehicles in the Central Denmark Region were equipped with a point-of-care cardiac troponin T device (Roche Cobas h232) for routine use in all patients with a suspected acute myocardial infarction. During the study period, 1 June 2012-30 November 2015, prehospital point-of-care cardiac troponin T measurements were performed in a total of 19,615 cases seen by the emergency medical service and 18,712 point-of-care cardiac troponin T measurements in 15,781 individuals were matched with an admission. A final diagnosis of acute myocardial infarction was confirmed in 2187 cases and a total of 2150 point-of-care cardiac troponin T measurements (11.0%) had a value ≥50 ng/l, including 966 with acute myocardial infarction (sensitivity: 44.2%, specificity: 92.8%). Patients presenting with a prehospital point-of-care cardiac troponin T value ≥50 ng/l had a one-year mortality of 24% compared with 4.8% in those with values <50 ng/l, log-rank: p<0.001. The following variables showed the strongest association with mortality in multivariable analysis: point-of-care cardiac troponin T≥50 ng/l (hazard ratio 2.10, 95% confidence interval: 1.90-2.33), congestive heart failure (hazard ratio 1.93, 95% confidence interval: 1.74-2.14), diabetes mellitus (hazard ratio 1.42, 95% confidence interval: 1.27-1.59) and age, one-year increase (hazard ratio 1.08, 95% confidence interval: 1.08-1.09).

CONCLUSIONS

Patients with suspected acute myocardial infarction and a prehospital point-of-care cardiac troponin T ≥50 ng/l have a poor prognosis irrespective of the final diagnosis. Routine troponin measurement in the prehospital setting has a high predictive value and can be used to identify high-risk patients even before hospital arrival so that they may be re-routed directly for advanced care at an invasive centre.

Diagnostic value of prehospital ECG in acute stroke patients

Objective:

To investigate the diagnostic yield of prehospital ECG monitoring provided by emergency medical services in the case of suspected stroke.

Methods:

Consecutive patients with acute stroke admitted to our tertiary stroke center via emergency medical services and with available prehospital ECG were prospectively included during a 12-month study period. We assessed prehospital ECG recordings and compared the results to regular 12-lead ECG on admission and after continuous ECG monitoring at the stroke unit.

Results:

Overall, 259 patients with prehospital ECG recording were included in the study (90.3% ischemic stroke, 9.7% intracerebral hemorrhage). Atrial fibrillation (AF) was detected in 25.1% of patients, second-degree or greater atrioventricular block in 5.4%, significant ST-segment elevation in 5.0%, and ventricular ectopy in 9.7%. In 18 patients, a diagnosis of new-onset AF with direct clinical consequences for the evaluation and secondary prevention of stroke was established by the prehospital recordings. In 2 patients, the AF episodes were limited to the prehospital period and were not detected by ECG on admission or during subsequent monitoring at the stroke unit. Of 126 patients (48.6%) with relevant abnormalities in the prehospital ECG, 16.7% received medical antiarrhythmic therapy during transport to the hospital, and 6.4% were transferred to a cardiology unit within the first 24 hours in the hospital.

Conclusions:

In a selected cohort of patients with stroke, the in-field recordings of the ECG detected a relevant rate of cardiac arrhythmia. The results can add to the in-hospital evaluation and should be considered in prehospital care of acute stroke.