Frequency of non-ST-segment elevation injury patterns on prehospital electrocardiograms.
ABSTRACT Prehospital electrocardiograms (ECGs) have been recommended to facilitate early diagnosis of ST-segment elevation myocardial infarction (STEMI). However, prehospital ECGs can also be used to triage patients with non-ST-segment elevation acute coronary syndromes, who comprise a majority of patients with ischemic events presenting by ambulance to overcrowded emergency departments.
We assessed the frequency of non-ST-segment elevation injury patterns on prehospital ECGs in patients with a chief complaint of chest pain evaluated by the emergency medical services (EMS) system.
We analyzed prehospital ECGs of patients with the chief complaint of chest pain during a nine-month period. The ECGs were divided into three categories: injury pattern; no injury pattern; and technically uninterpretable. Injury pattern criteria were as follows: 1) regional ST depression >or=1.0 mm; 2) regional T-wave inversion (TWI) >or=3 mm; 3) left bundle branch block (LBBB); and 4) regional ST-segment elevation >or=1.0 mm. Descriptive statistics with 95% confidence intervals (CIs) are presented.
Prehospital ECGs were obtained for 322 of 340 chest pain patients: 72% were men; the average age was 60 years (range 18-96 years). Seventy-seven ECGs (24%, 95% CI 19.3-28.9%) met the criteria for injury pattern, 230 (71%) did not show injury, and 15 (5%) were uninterpretable. Of the 77 ECGs that exhibited an injury pattern, 39 (51%) showed ST depression, seven (9%) TWI, seven (9%) LBBB, and 24 (31%) ST-segment elevation. Thus, non-ST-segment elevation injury patterns (ST depression/TWI/LBBB) accounted for 53 (17%, 95% CI 12.6-20.9) of the total 322 prehospital ECGs.
Our findings demonstrate a relatively high frequency (17%) of non-ST-segment elevation injury patterns on prehospital ECGs of patients who summon EMS because of chest pain. These results suggest the potential of prehospital ECGs to facilitate early triage in these high-risk chest pain patients who present to overcrowded emergency departments.
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ABSTRACT: The aims of this report are to (1) describe a novel prehospital 12-lead electrocardiogram (ECG) configuration and transmission procedure used in the Synthesized Twelve-lead ST Monitoring and Real-time Tele-electrocardiography Study and to (2) report on the frequency of arrhythmias in field ECGs compared with the first hospital ECG. The Synthesized Twelve-lead ST Monitoring and Real-time Tele-electrocardiography Study is a 5-year randomized clinical trial ending in 2008. All emergency vehicles responding to 911 calls in Santa Cruz County, Calif, have been equipped with portable monitor defibrillators with a special study software that (1) synthesizes a 12-lead ECG from 5 electrodes, (2) measures ST amplitudes in all 12 leads every 30 seconds, and (3) automatically transmits an ECG to the target emergency department if there is a change in ST amplitude of 200 microV in 1 lead or more or 100 microV in 2 contiguous leads or more lasting 2.5 minutes. An initial ECG is transmitted by paramedics, which activates the software. Subsequent transmissions of ST event ECGs occur automatically without paramedic decision making. Prehospital ECGs had a greater frequency of arrhythmias than the first hospital ECG in the group as a whole (n = 433; 33.3% vs 28.9%; P < or = .001), as well as the subgroup with acute coronary syndrome (n = 185; 30.3% vs 26.5%; P < or = .001). More tachyarrhythmias occurred in the field and slightly more bradyarrhythmias occurred at the time of the first hospital ECG. Prehospital continuous 12-lead ST-segment ischemia monitoring with computer-assisted automatic mobile telephone transmission of ST event ECGs to the target hospital is feasible. More arrhythmias occur in the prehospital phase than are evident on the first hospital ECG.Journal of electrocardiology 10/2006; 39(4 Suppl):S157-60. · 1.08 Impact Factor
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ABSTRACT: To describe time to electrocardiogram (ECG) acquisition, identify factors associated with timely acquisition, and evaluate the influence of time to ECG on adverse clinical outcomes. We measured the door-to-ECG time for emergency department patients enrolled in prospective chest pain registry. Clinical outcomes were defined as occurrence of myocardial infarction or death within 30 days of the visit. Among patients with acute coronary syndrome (ACS), 34% and 40.9% of patients with non-ST-elevation ACS and ST-elevation myocardial infarction (STEMI), respectively, had an ECG performed within 10 minutes of arrival. A delay in ECG acquisition was only associated with an increase risk of clinical outcomes in patients with STEMI at 30 days (odds ratio, 3.95; 95% confidence interval, 1.06-14.72; P = .04). Approximately one third of patients with ACS received an ECG within 10 minutes. A prolonged door-to-ECG time was associated with an increased risk of clinical outcomes only in patients with STEMI.American Journal of Emergency Medicine 02/2006; 24(1):1-7. · 1.70 Impact Factor
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ABSTRACT: Standardized reporting criteria for risk stratification studies of patients with potential acute coronary syndromes have been proposed. We sought to determine whether the categories in the recommended 6-item ECG classification system predict rates of 30-day death, myocardial infarction, and revascularization. We conducted a prospective cohort study of emergency department (ED) chest pain patients who presented to a tertiary care center during a 32-month period. The treating physician classified all ECGs into defined categories. Patients were followed up for 30 days to determine death, myocardial infarction, and revascularization. Our main outcome was the rate of triple composite endpoint of death, myocardial infarction, or revascularization at 30 days from ED presentation in relation to the ECG classification category. There were 3,814 patients who presented to the ED a total of 4,487 times during the study period. Patients had a mean (+/-SD) age of 51.8+/-15.9 years, were more likely to be women (59%) than men, and were most commonly black (68%). The relationship between initial ECG classification and 30-day outcome was highly significant (P<.001), with event rates ranging from 3.2% to 72.7%, depending on ECG classification category. The ECG classification system that is being recommended in the standardized guidelines predicts 30-day composite rates of death, acute myocardial infarction, and revascularization.Annals of emergency medicine 09/2004; 44(3):206-12. · 4.23 Impact Factor