Early rule out of acute myocardial infarction in ED patients: value of combined high-sensitivity cardiac troponin T and ultrasensitive copeptin assays at admission

Objective

We sought to evaluate the added value of ultrasensitive copeptin (us-copeptin) for early rule out of acute myocardial infarction in a prospective cohort of emergency department (ED) patients with acute chest pain.

Methods

This was a prospective study including consecutive patients with acute chest pain presenting to the ED within 12 hours of symptom onset. High-sensitivity cardiac troponin T (hs-cTnT, Roche Diagnostics, Meylan, France) and us-copeptin (ThermoFisher Scientific, Clichy, France) were blindly assayed from venous blood samples obtained at admission. Diagnosis was made by 2 ED physicians using all available data and serial cardiac troponin I as the biochemical standard. Diagnostic performances of us-copeptin combined with hs-cTnT were assessed using logistic regression. Analysis was conducted in all patients and in patients without ST-elevation myocardial infarction.

Results

A total of 194 patients were included (age, 61 [48-75] years; male sex, 63%). Acute myocardial infarction occurred in 52 (27%) patients, including non–ST-elevation myocardial infarction (NSTEMI) in 25 (13%). Patients with acute myocardial infarction had higher levels of hs-cTnT (50 [95% confidence interval, 19-173] ng/L) and us-copeptin (30 [13-113] pmol/L) at admission compared with those without (P < .05). Combination of markers significantly improved receiver operating characteristic area under the curve (from 0.89 [0.85-0.92] for hs-cTnT alone to 0.93 [0.89-0.97], P = .018). Sensitivity and negative predictive value were increased, particularly for NSTEMI diagnosis (sensitivity, 76% [54.9-90.6] to 96% [79.6-99.9]; negative predictive value, 95% [90.4-98.3] to 98.9% [94.2 to 100]).

Conclusion

Assessment of us-copeptin combined with hs-cTnT on ED admission could allow safe and early rule out of NSTEMI for patients with negative results on both markers and help identify patients who may be suitable for discharge.     

Utilization of coronary computed tomography angiography for exclusion of coronary artery disease in ED patients with low- to intermediate-risk chest pain: a 1-year experience

Objective

We describe our preliminary experience with coronary computed tomography angiography (CCTA) in emergency department (ED) patients with low- to intermediate-risk chest pain.

Methods

A convenience cohort of patients with low- to intermediate-risk acute chest pain presenting to a suburban ED in 2009 were prospectively enrolled if the attending physician ordered a CCTA for possible coronary artery disease. Demographic and clinician data were entered into structured data collection sheets required before any imaging. The results of CCTA were classified as normal, nonobstructive (1%-50% stenosis), and obstructive (>50% stenosis). Outcomes included hospital admission and death within a 6-month follow-up period.

Results

In 2009, 507 patients with ED chest pain had a CCTA while in the ED. The median (interquartile range) age was 54 (47-62) years; 51.5% were female. Thrombolysis in myocardial infarction risk scores were 0 (42.6%), 1 (42.2%), 2 (11.8%), 3 (2.4%), and 4 (1.0%). The results of CCTA were normal (n = 363), nonobstructive (n = 123), and obstructive (n = 21). Admission rates by CCTA results were obstructive (90.5%), nonobstructive (4.9%), and normal (3.0%). None of the patients with normal or nonobstructive CCTA died within the 6-month follow-up period (0%; 95% confidence interval, 0-0.9%).

Conclusions

Many ED patients with low- to intermediate-risk chest pain have a normal or nonobstructive CCTA and may be safely discharged from the ED without any associated mortality within the following 6 months.     

Outcome of chest pain patients discharged from a French emergency department: a 60-day prospective study

Background

Chest pain (CP) is a common complaint among patients presenting to the emergency department (ED). Previous studies suggest that between 2% and 5% of ED patients who present with CP and are sent home develop an acute coronary syndrome within 30 days. In France, no prospective data are available concerning the outcome of CP patients discharged from the ED.

Objective

The objective of our study was to determine the rate of adverse cardiac events (ACE) within a period of 60 days after discharge from the ED.

Methods

From October 2007 to February 2008, consecutive patients aged 25 years or more who presented to the ED with CP were prospectively included. Patients discharged from the ED were contacted by phone at 60 days to determine their clinical course and the occurrence of an ACE.

Results

There were 322 CP patients enrolled, representing 3.9% of all medical admissions to the ED; 40.4% of these patients were hospitalized and 59.6% were discharged. Three patients (1.6%) could not be contacted for follow-up, leaving 189 patients eligible for the study. The rate of ACE was 3.7%: one ST-segment elevation myocardial infarction and six non-ST-segment elevation myocardial infarctions. Follow-up revealed that 39.1% of patients saw a cardiologist and that 14.2% were readmitted for CP.

Conclusion

We found that CP is a frequent complaint in patients who present to our ED, and that a small proportion (3.7%) is mistakenly discharged and presents with an ACE during the 60-day follow-up period.     

Acute Aortic Regurgitation with Myocardial Infarction: An Important Clue for Aortic Dissection

Background

Aortic dissection is an important cause of acute chest pain that should be rapidly diagnosed, as mortality increases with each hour this condition is left untreated. The diagnosis can be challenging, especially if concomitant myocardial infarction is present. Echocardiography is an important tool for the differential diagnosis.

Objectives

To stress the importance of recognizing aortic regurgitation for the differentiation of myocardial infarction and aortic dissection.

Case Report

An 80-year-old woman was admitted to our hospital with chest pain that was diagnosed as inferior and lateral wall myocardial infarction based on electrocardiographic findings. The diagnosis was reevaluated when aortic regurgitation was detected on echocardiography. Closer inspection of the ascending aorta revealed a dissection flap as the cause of aortic regurgitation.

Conclusion

Detection of aortic regurgitation in a patient with myocardial infarction and normal valves should prompt the search for a possible aortic dissection, whether or not the dissection flap can be visualized.     

Prediction of myocardial infarction risk in older patients with acute coronary syndrome

Purposes

To identify bedside variables that aid in diagnosis of acute coronary syndrome (ACS) and might facilitate rapid triage of patients aged ≥65 years.

Basic Procedures

Prospective, observational study of consecutive patients aged ≥65 years with suspicion of ACS presenting to our emergency department (ED). Patients' medical characteristics were collected at baseline and during a 1-month follow-up period. We identified variables independently associated with ACS by multivariate analyses and bootstrapping techniques.

Main Findings

Among 399 patients, 124 (31.1%) received a diagnosis of ACS (61 acute myocardial infarction, 63 unstable angina). We surveyed multiple clinical and ECG variables to develop a predictive model which included the following variables: male sex, history of coronary artery disease, typical chest pain, dyspnea, epigastric pain, pathological Q-wave, ST-segment elevation (area under the receiver operating characteristic curve (AUC) 0.79, 95% confidence interval 0.71 to 0.82). With the addition of cardiac troponin I to the model the AUC increased to 0.83 (0.79 to 0.88). We used these findings to create the Heart Attack Risk for aged Patient (HARP) scale. Our data suggest that patients with a low HARP score might be safely managed without further testing.

Principal Conclusions

A model based on variables easily available at ED presentation from history, physical examination, and electrocardiography, can help ED physicians to identify seniors at very low risk of ACS.     

Heart-type fatty acid binding protein and the diagnosis of acute coronary syndrome in the ED

Background

In combination with cardiac troponin, heart-type fatty acid binding protein (h-FABP)—a biomarker of myocardial necrosis—offers the possibility of rapidly eliminating the diagnosis of acute myocardial infarction (AMI).

Objective

The main objective of this study was to assess the incremental value of h-FABP to cardiac troponin for a rapid elimination of AMI, according to the pretest probability (PTP) of AMI.

Methods

In consecutive patients presenting to emergency departments (ED) with chest pain less than 6 hours suggestive of AMI, h-FABP levels were measured, blinded to the ED physicians, who were asked to quote the PTP of AMI. The discharge diagnosis was adjudicated by 2 independent experts, blind to the h-FABP level.

Results

Three hundred seventeen patients (mean age of 57 years) were included in whom 149 had (47%) low, 117 (37%) moderate, and 51 (16%) high PTP. The final diagnosis was AMI in 45 patients (14%), including 16 STEMIs (5%). The negative predictive value for diagnostic elimination of AMI of an h-FABP less than 3 μg/L, combined with a negative cTnI was not higher than that of cardiac troponin I (cTnI) alone (96% [95% confidence interval, 93%-98%] vs 95% [93%-98%]), regardless of the PTP). Even in the low-PTP group, we did not demonstrate a significant improvement in negative predictive value with the addition of h-FABP, compare with that of cTnI alone (100% [97%-100%] vs 99% [96%-100%]).

Conclusion

In triage of patients with chest pain, use of h-FABP does not provide useful additional information to cTnI for excluding the diagnosis of ST-elevation myocardial infarction and non–ST-elevation myocardial infarction diagnosis, whatever the PTP.     

Application of the TIMI risk score in ED patients with cocaine-associated chest pain

Objective

The TIMI risk score has been validated as a risk stratification tool in emergency department (ED) patients with potential acute coronary syndrome. The goal of this study was to assess its ability to predict adverse cardiovascular outcomes in cocaine-associated chest pain.

Methods

This was a prospective cohort study of ED patients with chest pain with cocaine use. Data included demographics, medical history, and TIMI risk score. The main outcomes were acute myocardial infarction, revascularization, or death within 30 days of ED presentation.

Results

There were 261 patient visits. Patients were 43.2+8 years old, 73% male, 92% black, and 75% smokers. There were 33 patients with the composite outcome. The incidence of 30-day outcomes according to TIMI score is as follows: TIMI 0, 3.7% (95% CI, 0.1-8.3); TIMI 1, 13.2% (5.7-20.7); TIMI 2, 17.1% (4.3-29.8); TIMI 3, 21.4% (4.4-38.4); TIMI 4, 20.0% (0.1-43.6); TIMI 5/6, 50.0% (0.1-100).

Conclusions

The TIMI risk score has no clinically useful predictive value in patients with cocaine-associated chest pain.     

Superior outcome with direct catheter laboratory access vs ED-activated primary percutaneous coronary intervention

Aims

Admitting patients directly to a heart attack center (HAC) catheter laboratory for primary percutaneous coronary intervention (PPCI) bypassing the emergency department (ED) might be beneficial in delivering treatment of ST-elevation myocardial infarction with superior outcome.

Methods

In this analysis, the clinical outcome of service redesign of the PPCI pathway from ED triggered to a direct catheter laboratory HAC access was assessed in 361 consecutive patients with ST-elevation myocardial infarction treated with a PPCI.

Results

A total of 200 patients were admitted via the ED, and 161 were admitted directly to the HAC. Door-to-balloon times and call-to-balloon times were significantly better in the HAC group (median [interquartile range] door-to-balloon times and call-to-balloon times were 39 [26, 53] and 106 [91, 132] minutes, respectively) in comparison with the ED group (82 [49,120; P < .0001] and 130 [103, 164] minutes, respectively [P = .0005]). A nonsignificant trend to a lower 30-day (5% in the HAC group and 6% in the ED group) and 17-month (8% in HAC group and 11% in ED group) mortality was seen in the HAC group (P = .63). Composite end point analysis of left ventricular ejection fraction less than 50%, thrombolysis in myocardial infarction grades 0 and 1, and myocardial blush scores 0 and 1 showed that a significantly higher number of patients in the ED group experienced at least 1 of the composite events in comparison with the patients in the HAC group (P = .01).

Conclusion

A direct-access catheter laboratory (HAC) model of PPCI bypassing the ED should be the favored approach to service delivery with superior outcome.     

Killip classification and glucose level in patients with acute myocardial infarction

Objective

Killip classification is a valuable prognostic stratification for patients with acute myocardial infarction. Patients with high initial glucose levels also have adverse outcomes. We hypothesize that an increase in the Killip classification rank of patients with acute myocardial infarction might be associated with increase in initial glucose levels.

Methods

In a retrospective cohort study, patients receiving percutaneous coronary angiography after an acute myocardial infarction were enrolled. Patients were accorded Killip classifications, and the data were compared using the χ² and 1-way analysis of variance tests.

Results

The study was conducted on 246 eligible subjects. Higher initial glucose levels were associated with higher rate of hospitalization within 1 year as well as mortality (P < .05). Glucose levels among the 4 Killip classes were different (P < .05).

Conclusion

Patients ranked in the higher Killip classes had higher glucose levels than those ranked in the lower classes.     

Identification of Splenic Infarction by Emergency Department Ultrasound

Background

Splenic rupture or infarction can occur secondary to acute infectious mononucleosis. Patients with abdominal pain and known or suspected infectious mononucleosis mandate evaluation for these complications, which can have significant morbidity or mortality.

Case Report

An 18-year old man presented to the emergency department (ED) with a 2-day history of left upper quadrant abdominal pain. He had been diagnosed with mononucleosis 4 days before his ED presentation. Physical examination was notable for focal left upper quadrant tenderness. The treating physician's principal diagnostic considerations were splenic rupture or infarction secondary to mononucleosis. Point-of-care ultrasound was performed by the emergency physician, demonstrating multiple hypoechoic areas in the splenic parenchyma with absent Doppler flow, consistent with multiple splenic infarcts. The patient was admitted for observation, managed conservatively, and had an uneventful course.

Conclusion

Emergency ultrasound of the spleen can allow rapid diagnosis of splenic infarction and exclusion of splenic rupture in a patient at risk for splenic pathology.     

Coronary artery disease progression in patients without significant stenosis on coronary computed tomographic angiography

Background

Patients who present to the emergency department (ED) with symptoms of potential acute coronary syndrome (ACS) can be safely discharged home after a coronary computed tomographic angiography (CTA) with a negative result. However, the duration of time for which a negative coronary CTA scan result can be used to inform decision making when patients have recurrent symptoms is not known.

Objective

We examined patients who received more than 1 coronary CTA for evaluation of ACS to determine whether they had disease progression. Our main outcome was whether any patient had a maximal stenosis cross the threshold from noncritical (<50% maximal stenosis) to potentially critical disease.

Methods

We performed a structured comprehensive record search of all coronary CTAs performed from 2005 to 2010 at a tertiary care health system. Low-to-intermediate risk ED patients who received 2 or more coronary CTAs, at least 1 from an ED evaluation for potential ACS, were identified. Patients who were revascularized between scans were excluded. We collected demographic data, clinical course, time between scans, and number of ED visits between scans. Record review was structured and done by trained abstractors. Our main outcome was progression of coronary stenosis between scans, specifically crossing the threshold from noncritical to potentially critical disease.

Results

Overall, 32 patients who received repeat imaging were identified (median age, 45 years; interquartile range, 37.5-48; 56% female; 88% black). The median time between studies was 27.3 months (interquartile range, 18.2-33.2). Twenty-two patients did not have stenosis in any vessel on either coronary CTA, 2 studies showed increasing stenosis of less than 20%, and the rest showed “improvement” due to better imaging quality. No patient initially below the 50% threshold subsequently exceeded it (0%; 95% confidence interval, 0-11.0%). No patient had acute myocardial infarction or revascularization either between scans or within a year after the repeated imaging.

Conclusion

Repeated imaging potentially may not be warranted within 2 years of a negative coronary CTA result. The low rate of progression from subcritical to critical disease is consistent with observations in patients who have had prior negative cardiac catheterizations.     

Hyperacute T-waves: Wolff-Parkinson-White Pattern or Acute Coronary Syndrome?

Background

Pre-excitation syndromes can elicit electrocardiogram (ECG) abnormalities that are nearly identical to those associated with acute myocardial ischemia. In the presence of atypical symptoms, stable hemodynamics, and unremarkable levels of cardiac enzymes, the decision whether to subject these patients to coronary angiography, or even non-invasive testing, can be difficult.

Objective

To understand that pre-excitation syndrome can mimic acute myocardial injury, but should not preclude a complete ischemic work-up.

Case Report

A 53-year-old man with Wolff-Parkinson-White pattern and coronary artery disease risk factors presented with new-onset substernal chest pain. A baseline ECG was significant for hyperacute T waves. After refusing cardiac catheterization, he was admitted to the cardiac care unit for intravenous heparin and eptifibatide. Although his stay was unremarkable and resting echocardiogram showed normal contractility and valve function, treadmill stress testing was negative for ischemic change, but revealed ST-segment depression with maximum stress in the lateral precordial leads. This was thought to be a “false positive” secondary to his conduction abnormality.

Conclusion

No reliable algorithm exists for making an ECG diagnosis of myocardial infarction in the presence of a pre-excitation syndrome. Similarly, current non-invasive modalities have limitations in detecting jeopardized myocardium. If acute or hyperacute injury is suspected, the patient should be emergently referred for cardiac catheterization.     

Acute kidney injury risk in patients with ST-segment elevation myocardial infarction at presentation to the ED

Introduction

Acute kidney injury (AKI) is common in acute myocardial infarction (AMI) patients and has serious prognostic implications. The early identification of patients at risk of developing AKI at the emergency department (ED) can reduce its incidence.

Methods

Patients with ST-segment elevation myocardial infarction (STEMI) at the ED were included. Associated factors playing a role at ED presentation and during hospitalization were collected, and independent risk factors of developing AKI were assessed.

Results

Mean age among patients (n = 406, 69.7% male) was 62.5 ± 12.5 years. At ED admission, the mean glomerular filtration rate (GFR) was 70.5 ± 28.1 mL/min per 1.73 m², and 140 (34.5%) patients had a GFR < 60 mL/min per 1.73 m². Eighty-three patients (20.4%) developed AKI: 47 (11.6%) with stage 1, 26 (6.4%) with stage 2 and 10 (2.5%) with stage 3. Mortality was 11.8% and was higher in patients with AKI (34.9% vs 5.9%, P < .0001). Univariate analysis disclosed age, reduced GFR at presentation, severe Killip class, heart rate and longer door-to-needle time as risk factors to develop AKI. Moreover, these patients received less β-blocker and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker in the ED. Multivariate analysis revealed that age, Killip class, heart rate, door-to-needle time, and β-blocker non-use were independent factors associated with AKI. These factors provided the ED physician with good accuracy in identifying patients at high risk of developing AKI.

Conclusion

Factors associated with AKI in STEMI patients allowed physicians to identify patients at high risk in the ED. Moreover, reduced door-to-needle time and β-blocker use were associated with renal protection in AMI patients.     

ED triage of patients with acute myocardial infarction: predictors of low acuity triage

Objective

Virtually all emergency department (ED) patients receive an ED triage assessment that determines their priority to be seen by a physician. Previous research found that half of patients who are having an acute myocardial infarction (AMI) are given a low priority triage score, which is associated with delays in electrocardiogram (ECG) acquisition and reperfusion therapy. We sought to determine some of the reasons why ED triage is failing in these patients.

Methods

We conducted a retrospective cohort analysis of a population-based cohort of AMI patients admitted to 102 acute care hospitals in Ontario, Canada, from July 2000 to March 2001. We examined 10 potential patient- and hospital-level predictors of low acuity triage: age, sex, number of comorbidities, arrival mode, socioeconomic status, time of day, day of week, ED AMI volume, hospital type, and department use of triage ECGs.

Results

Mean age of the 3088 patients was 67.5 (SD, 14.0), and 65% were men. In adjusted quantile regression analyses, low acuity triage was independently associated with ED AMI volume (odds ratio [OR], 0.44 at very high volume centers), arrival mode (OR, 0.60 for ambulance arrival), sex (OR, 0.80 for males), age (OR, 1.1 per 10 years of age), and a low number of comorbidities (OR, 0.92 for every cardiac co-morbidity).

Conclusions

Low acuity ED triage of AMI patients may be predicted by several patient- and hospital-level characteristics. Focusing future interventions on these factors may improve ED triage and, subsequently, time to initial ECG and reperfusion, in this patient group.     

Spontaneous Coronary Artery Dissection in a 27-Year-Old Woman

Background

Spontaneous coronary artery dissection (SCAD) causes acute coronary syndromes or sudden death in young patients who are often lacking classic coronary disease risk factors. Systemic inflammatory and connective tissue diseases have been suggested as risk factors for SCAD.

Objective

To review the risk factors, diagnosis, and management of this uncommon but life-threatening disease.

Case Report

We report a case of a 27-year-old woman with a history of an ill-defined inflammatory arthropathy who presented with an acute ST-elevation myocardial infarction. SCAD was diagnosed by coronary angiography. Percutaneous coronary intervention was attempted but was unsuccessful. The patient recovered uneventfully with medical management and was ultimately diagnosed with systemic lupus erythematosus.

Conclusions

SCAD is a rare but important cause of acute coronary syndromes and sudden death. It commonly occurs in young women. Although pregnancy is the most well-established risk factor, systemic inflammatory and connective tissue diseases have also been suggested as risk factors.     

Safety of a rapid diagnostic protocol with accelerated stress testing

Background

Most patients at low to intermediate risk for an acute coronary syndrome (ACS) receive a 12- to 24-hour “rule out.” Recently, trials have found that a coronary computed tomographic angiography–based strategy is more efficient. If stress testing were performed within the same time frame as coronary computed tomographic angiography, the 2 strategies would be more similar. We tested the hypothesis that stress testing can safely be performed within several hours of presentation.

Methods

We performed a retrospective cohort study of patients presenting to a university hospital from January 1, 2009, to December 31, 2011, with potential ACS. Patients placed in a clinical pathway that performed stress testing after 2 negative troponin values 2 hours apart were included. We excluded patients with ST-elevation myocardial infarction or with an elevated initial troponin. The main outcome was safety of immediate stress testing defined as the absence of death or acute myocardial infarction (defined as elevated troponin within 24 hours after the test).

Results

A total of 856 patients who presented with potential ACS were enrolled in the clinical pathway and included in this study. Patients had a median age of 55.0 (interquartile range, 48-62) years. Chest pain was the chief concern in 86%, and pain was present on arrival in 73% of the patients. There were no complications observed during the stress test. There were 0 deaths (95% confidence interval, 0%-0.46%) and 4 acute myocardial infarctions within 24 hours (0.5%; 95% confidence interval, 0.14%-1.27%). The peak troponins were small (0.06, 0.07, 0.07, and 0.19 ng/mL).

Conclusions

Patients who present to the ED with potential ACS can safely undergo a rapid diagnostic protocol with stress testing.     

Prospective validation of Thrombolysis in Myocardial Infarction and front door Thrombolysis in Myocardial Infarction risk scores in Chinese patients presenting to the ED with chest pain

Background

Chest pain is a common complaint among emergency department (ED) patients. The Thrombolysis in Myocardial Infarction (TIMI) and front door TIMI (FDTIMI) scores are used to risk stratify chest pain patients in many Western countries; they have not been validated in patients with undifferentiated chest pain in Asia. Our objective was to establish the relationship between the TIMI and FDTIMI scores and the 30 day rate of major adverse cardiac outcomes (MACE) in Chinese patients presenting to the ED with chest pain.

Methods

Prospective, single-center, observational cohort study of consecutive patients presenting with chest pain from July 2009 until March 2010 to a Hong Kong university hospital ED. Data collected included patient characteristics, TIMI items and past medical and medication history. Primary outcome was MACE within 30 days of presentation. MACE was a composite outcome of any of the following: death (all causes), readmission with myocardial infarction, acute coronary syndrome not diagnosed at initial ED presentation and coronary revascularization.

Results

One thousand patients recruited with complete 30-day follow-up. STEMI patients (n = 75) were excluded. Mean patient age 66.8 ± 13.9 years; 51.7% male. 119 (12.9%) patients had MACE within 30 days of presentation. The incidence of MACE ranged from 0 for TIMI0 to 37.5% for patients with TIMI6/7. Increasing TIMI and FDTIMI scores were associated with a higher incidence of MACE.

Conclusions

This validation suggests that the TIMI/FDTIMI scores can be employed in Hong Kong Chinese; they may be useful for risk stratification of Chinese ED patients with undifferentiated chest pain elsewhere.     

Lack of association between left bundle-branch block and acute myocardial infarction in symptomatic ED patients

Objective

Guidelines recommend treating patients with a new or presumed new left bundle-branch block (LBBB) similar to those with an acute ST-segment elevation myocardial infarction. It is often unclear which emergency department (ED) patients with potentially ischemic symptoms actually have an acute myocardial infarction (AMI), even in the setting of LBBB. Our null hypothesis was that in ED patients with potential AMI, the presence of a new or presumed new LBBB would not predict an increased likelihood of AMI.

Methods

This was an observational cohort study. Patients older than 30 years who presented with chest pain or other ischemic equivalent and had an electrocardiogram (ECG) to evaluate potential acute coronary syndrome (ACS) were enrolled. Data collected include demographics, history, ECG, and cardiac markers. Electrocardiograms were classified according to the standardized guidelines, including LBBB not known to be old (new or presumed new LBBB), LBBB known to be old, or no LBBB. The hospital course was followed, and 30-day follow-up was performed on all patients. Our main outcome was AMI.

Results

There were 7937 visits (mean age, 54.3 ± 15 years, 57% female, 68% black): 55 had new or presumed new LBBB, 136 had old LBBB, and 7746 had no LBBB. The rate of AMI was not significantly different between the 3 groups (7.3% vs 5.2% vs 6.1%; P = .75). Revascularization (7.8% vs old 5.2% vs 4.3%; P = .04) and coronary artery disease were more common in patients with new or presumed new LBBB (19.2% vs 11.9% vs 10.1%; P = .0004).

Conclusions

Despite guideline recommendations that patients with potential ACS and new or presumed new LBBB should be treated similar to STEMI, ED patients with a new or presumed new LBBB are not at increased risk of AMI. In fact, the presence of LBBB, whether new or old, did not predict AMI. Caution should be used in applying recommendations derived from patients with definite AMI to ED patients with potential ACS that may or may not be sustaining an AMI.     

The Impact of Prehospital 12-Lead Electrocardiograms on Door-to-Balloon Time in Patients With ST-Elevation Myocardial Infarction

Introduction

Multiple strategies have been implemented to reduce door-to-balloon times. The purpose of this study was to compare door-to-balloon times between ST-elevation myocardial infarction (STEMI) patients who arrived at the emergency department by ambulance with a pre-hospital electrocardiogram (ECG), to those who self-transported and had an ECG on ED arrival.

Methods

This retrospective, comparative study evaluated differences in door-to-balloon times from October 2006 to December 2009 between STEMI patients that had a 12-lead ECG done in the ambulance prior to ED arrival and patients who self-transported and had an ECG on ED arrival.

Results

Of the 367 patients, 62% (n = 228) arrived by ambulance and 38% (n = 139) self-transported to the emergency department. Door-to-balloon times were 30 minutes less (P < .001) than patients who were self-transported.

Discussion

Door-to-balloon times can be reduced when chest pain patients are transported to the emergency department by ambulance. The paramedics are equipped to perform an ECG, thereby making a preliminary diagnosis of STEMI. The emergency department can them prepare for potential angioplasty or percutaneous coronary intervention. An opportunity exists for emergency nurses to educate the public about the importance of calling 911 for chest pain.     

Diagnostic performance of initial salivary alpha-amylase activity for acute myocardial infarction in patients with acute chest pain

Background

To rule out acute myocardial infarction (AMI) in chest pain patients constitutes a diagnostic challenge to emergency department (ED) physicians.

Study Objectives

To evaluate the diagnostic value of measuring salivary alpha-amylase (sAA) activity for detecting AMI in patients presenting to the ED with acute chest pain.

Methods

sAA activity was measured in a prospective cohort of 473 consecutive adult patients within 4 h of onset of chest pain. Comparisons were made between patients with a final diagnosis of AMI and those with non-AMI. Univariate analysis and multiple logistic regression model were used to identify independent clinical predictors of AMI.

Results

Initial sAA activity in the AMI group (n = 85; 266 ± 127.6 U/mL) was significantly higher than in the non-AMI group (n = 388; 130 ± 92.8 U/mL, p < 0.001). sAA activity levels were also significantly higher in patients with ST elevation AMI (n = 53) compared to in those with non-ST elevation AMI (n = 32) (300 ± 141.1 vs. 210 ± 74.1 U/mL, p < 0.001). The area under the receiver operating characteristic curve of sAA activity for predicting AMI in patients with acute chest pain was 0.826 (95% confidence interval [CI] 0.782–0.869), with diagnostic odds ratio 10.87 (95% CI 6.16–19.18). With a best cutoff value of 197.7 U/mL, the sAA activity revealed moderate sensitivity and specificity as an independent predictor of AMI (78.8% and 74.5%).

Conclusions

High initial sAA activity is an independent predictor of AMI in patients presenting to the ED with chest pain.