Improving patient flow in acute coronary syndromes in the face of hospital crowding

Background

The current paradigm for the evaluation of patients with suspected acute coronary syndromes (ACS) in the emergency department (ED) is focused on the identification of patients with active underlying coronary disease. The majority of patients evaluated in the ED setting do not have active underlying cardiac disease.

Objective

To measure the effect of bedside point-of-care (POC) cardiac biomarker testing on telemetry unit admissions from the ED. Furthermore, to evaluate the effect telemetry admissions have on ED length of stay (LOS) and overall hospital LOS.

Methods

Primary data were collected over two 6-month periods in an urban teaching hospital ED. This was an observational cohort study conducted pre- and post- availability of a POC testing platform for cardiac biomarkers. Major measures included number of overall telemetry admissions, ED LOS, hospital LOS, and disposition. Patients were followed at 30 days for significant cardiac events, repeat ED visit or admission, and death.

Results

In the post-implementation period there was a 30% (95% confidence interval [CI] 36–44%) reduction in admissions to telemetry with a 33% (95% CI 26–39%) reduction in ED LOS and a 20% (95% CI 7–34%) reduction in hospital LOS. There was a 62% reduction in overall mortality between the pre-implementation period and the post-implementation period (p = 0.001).

Conclusion

The focused use of a rapid cardiac disposition protocol can dramatically impact resource utilization, expedite patient flow, and improve short-term outcomes for patients with suspected ACS.     

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.     

A Case of Spontaneous Coronary Artery Dissection: It is Not Always Plaque Rupture

Background

Spontaneous coronary artery dissection (SCAD) is an extremely rare cause of acute coronary syndrome (ACS). Patients may present with a broad spectrum of clinical scenarios, ranging from angina pectoris to myocardial infarction, cardiogenic shock, and sudden death. Standard therapy has not been established; current treatments range from conservative management to percutaneous revascularization or coronary artery bypass surgery.

Objective

SCAD greatly mimics ACS, and this diagnosis should be considered when evaluating young patients who present with ACS with or without classical risk factors for coronary artery disease.

Case Report

We report a case of a 45-year old man who presented with chest pain typical of ACS. He had no risk factors except for a smoking history of 2.5 pack-years. Once the clinical findings suggested acute inferolateral myocardial infarction, the patient underwent emergent cardiac catheterization, which revealed left anterior descending coronary artery dissection. This in itself is not a common cause of inferolateral ST elevation changes on electrocardiogram.

Conclusion

This case highlights the fact that although SCAD is a rare entity, it is increasingly being recognized as a significant cause of ACS. Urgent angiography should be considered if SCAD is suspected, because early diagnosis and appropriate management significantly improve the outcome in these patients.     

Stress testing in young low-risk patients with potential acute coronary syndromes

Objective

Young patients are at low risk for an acute coronary syndrome (ACS); however, many of these patients still enter a “rule-out ACS” pathway and receive stress testing. We hypothesized that stress testing in patients younger than 40 years without known coronary disease will not identify patients at high risk for 30-day adverse cardiovascular events.

Methods

We conducted a cohort study of patients younger than 40 years evaluated in the emergency department for potential ACS. Patients were excluded if they used cocaine, had known cardiac disease, or had an abnormal electrocardiogram. Patients were followed up in-house; follow-up was performed by direct telephone contact and medical record review. The main outcome was a composite of death, acute myocardial infarction (AMI), and revascularization at 30 days. Comparisons between patients with and without stress testing were done using χ² or t test, as appropriate; 95% confidence intervals were reported for the main outcomes.

Results

Of 8816 patient visits, 1144 patients met inclusion criteria. Within 30 days, 82 patients (7.2%) received stress testing, 2 of whom led to cardiac catheterization. Death (n = 2), AMI (n = 3), and revascularization (n = 1) were not different between patients who did and did not receive stress testing (2.4% [0.2%-8.5%] vs 0.4% [0.1%-1.0%]).

Conclusion

The 30-day cardiovascular complication rate is not different between young patients without known heart disease who do and do not receive stress testing when they present with symptoms of a potential ACS. Testing of young patients at low risk for disease should be reconsidered.     

Predictive value of electrocardiogram in diagnosing acute coronary artery lesions among patients with out-of-hospital-cardiac-arrest

Aims

Acute coronary lesions are known to be the most common trigger of out of hospital cardiac arrest (OHCA). Aim of the present study was to assess the predictive value of ST-segment changes in diagnosing the presence of acute coronary lesions among OHCA patients

Methods

Findings of coronary angiography (CA) performed in patients resuscitated from OCHA were retrospectively reviewed and related to ST-segment changes on post-ROSC electrocardiogram (ECG)

Results

Ninety-one patients underwent CA after OHCA; 44% of patients had ST-segment elevation and 56% of patients had other ECG patterns on post-ROSC ECG. Significant coronary artery disease (CAD) was found in 86% of patients; CAD was observed in 98% of patients with ST-segment elevation and in 77% of patients with other ECG patterns on post-ROSC ECG (p = 0.004). Acute or presumed recent coronary artery lesions were diagnosed in 56% of patients, respectively in 85% of patients with ST-segment elevation and in 33% of patients with other ECG patterns (p < 0.001). ST-segment analysis on post-ROSC ECG has a good positive predictive value but a low negative predictive value in diagnosing the presence of acute or presumed recent coronary artery lesions (85% and 67%, respectively)

Conclusions

Electrocardiographic findings after OHCA should not be considered as strict selection criteria for performing emergent CA in patients resuscitated from OHCA without obvious extra-cardiac cause; even in the absence of ST-segment elevation on post-ROSC ECG, acute culprit coronary lesions may be present and considered the trigger of cardiac arrest     

Patients with coronary disease fail observation status at higher rates than patients without coronary disease

Background

Few studies have evaluated emergency department (ED) observation unit chest pain protocols for optimal patient characteristics and admission rates. At our 35?000-visits/y ED, we implemented a chest pain protocol for our observation unit that allowed emergency physicians to admit patients with known coronary artery disease (CAD).

Methods

We performed a retrospective chart review of all observation unit patients admitted under the chest pain protocol from April 1, 2006, to May 31, 2007. We compared the outcomes of patients who had a history of CAD with those who did not.

Results

Five hundred thirty-one patients were admitted to the observation unit under the chest pain protocol for the 14-month study period. Of these patients, 125 (23.5%) had a history of CAD. Patients with a history of CAD had a higher inpatient admission rate ( 24% vs 8.6%; P < .001), higher rate of a positive stress test or positive coronary computed tomographic scan (32.3% vs 6.9%; P < .001), a higher rate of cardiac catheterization (12% vs 5.9%; P = .02), and a higher rate of stent placement or coronary artery bypass graft (CABG) (7.2% vs 2.2%; P = .007). In multivariate analysis, patient history of CAD was an independent predictor of hospital admission (P = .005) and stent placement or CABG (P = .030).

Conclusion

Patients with known CAD who were admitted to the ED observation unit failed observation status (ie, required hospitalization) and had higher rates of positive testing than those without CAD.     

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.     

New Antiplatelet Agents and the Role of Platelet Function Testing in Acute Coronary Syndromes

Background

Dual antiplatelet therapy is a guideline mandated for patients with acute coronary syndromes (ACS). Despite its use, thrombotic events continue to occur both early and late. Platelet function testing has been used to define the in vitro effects of new antiplatelet agents, and it has been suggested that it be used to choose therapy. The role of platelet function testing, particularly with newer antiplatelet agents, remains unclear.

Objective

We review the rationale for platelet function testing and its application in monitoring patients on antiplatelet therapy. We also review recent clinical trials of newer antiplatelet agents. On the basis of this review, we reach conclusions on the current role of antiplatelet function testing in monitoring modern antiplatelet therapy and the role of the new antiplatelet agents in the treatment of ACS.

Methods

We reviewed recent publications on platelet function testing and clinical trials of newer antiplatelet therapies compared with clopidogrel.

Results

Platelet function testing is complex, but there is now a bedside test, VerifyNow. High platelet reactivity has been associated with worse cardiovascular outcomes in patients undergoing percutaneous coronary intervention. Recent clinical trials have not found any advantage in outcomes in patients who have their therapy adjusted by monitoring their platelet function. Newer agents, prasugrel, ticagrelor, and cangrelor, produce more rapid, complete, less variable effects on platelet function than clopidogrel. Prasugrel was found to improve outcomes compared with clopidogrel in patients with ACS undergoing percutaneous intervention. Ticagrelor is beneficial in all patients with ACS and reduces cardiovascular mortality compared with clopidogrel. Cangrelor improves outcomes in patients undergoing stenting. Recent studies to assess the role of platelet function monitoring of the effects of clopidogrel and modifying treatments have not been successful.

Conclusion

Recent clinical trials have indicated that newer antiplatelet agents have advantages over clopidogrel in the treatment of ACS. Platelet function testing gives us a guide to the timing, efficacy, and variability of therapy and can correlate with poor patient outcomes; however, the use of antiplatelet function testing to tailor therapy does not seem appropriate.     

The use of exercise stress testing for the management of low-risk patients with chest pain

Objective

This retrospective study assessed the contribution of exercise stress testing (EST) in the evaluation of patients with low risk for coronary heart disease who presented to the emergency department (ED) with chest pain.

Basic Procedures

The study included 175 patients who presented to the ED with chest pain and underwent EST between January 1, 2005, and November 30, 2006.

Main Findings

After the EST, 113 patients were discharged, and 62 were admitted. Exercise stress testing's positive predictive value for coronary artery disease among admitted patients was 35.7%, and sensitivity was 95.2%.Exercise stress testing's negative predictive value among discharged patients was 99.1%. None of the 113 discharged patients returned to the ED for cardiac reasons during the 30-day follow-up period.

Principal Conclusion

A chest pain unit or a parallel facility for evaluating patients with chest pain and with low risk for active coronary disease is necessary for detecting low-risk patients who eventually need cardiac intervention.     

Short- and long-term cardiac events in patients with chest pain with or without known existing coronary disease presenting normal electrocardiogram

Aim

The aim of this study is to evaluate incidence of adverse cardiac events in patients with chest pain with or without known existing coronary disease presenting normal electrocardiogram (ECG) and initial troponin.

Methods

Prospective, nonrandomized study enrolled low-risk patients with normal ECG and troponin on admission who underwent observation and/or stress testing by unstandardized clinical judgment. Patients who experienced recurrent angina or positive ECGs or positive troponins during observation or patients with positive stress testing were admitted; otherwise, they were discharged.

End Point

The end points are cardiac events at short- and long-term follow-up including cardiovascular death, myocardial infarction, unstable angina, and revascularization.

Results

Of 5656 patients considered, 1732 with ischemic ECG were initially admitted and, therefore, excluded from the analysis; 2860 with pleuritic chest pain and normal ECG were discharged; 1064 with visceral chest pain and normal ECG were enrolled. Patients with known coronary disease (45%) were older and likely presented known vascular disease. Patients with known vascular disease, older age, female sex, diabetes mellitus, and lower chest pain score were likely managed with observation. In patients with known coronary disease as compared with patients without, overall cardiac events account for 35% vs 14%, respectively (P < .001), as follows: in-hospital, 23% vs 10%, (P < .001); 1 month, 4% vs 2% (P = .133); and 9.9 ± 4.9 months, 8% vs 2%, respectively (P < .001).

Conclusions

One-third of patients with chest pain with known coronary disease, negative ECG, and biomarkers were subsequently found to have adverse cardiac events. The value of this research for an emergency medicine audience could be extended to all clinicians and general practitioners beyond cardiologists.     

Impact of renal dysfunction on acute coronary syndrome evaluation in observation unit patients

Objectives

The impact of renal disease on risk stratification of patients at low risk for potential acute coronary syndrome has not been well defined. The objective of this study was to document the prevalence of renal dysfunction and assess the association between renal impairment and abnormal cardiac evaluation in observation unit (OU) patients.

Methods

Retrospective cohort study at an academic medical center OU. Data were abstracted using predetermined definitions of data outcomes by trained abstractors. Patients had symptoms consistent with acute coronary syndrome and did not have obvious evidence of acute MI or ischemia on electrocardiogram, unstable vital signs, abnormal cardiac markers, serious arrhythmias, or uncontrollable chest pain. Observation patients received serial cardiac markers and electrocardiograms, with the majority receiving stress testing at treating physician discretion. Patients were stratified by glomerular filtration rates (GFR) at cut-off points of less than 60 and less than 90 mL/min per 1.73 m². Odds ratios were calculated for stress test findings of inducible ischemia or hospital admission.

Results

Five hundred and twenty-nine out of 545 patients had complete data and were enrolled. Sixty-nine (13%) patients had a GFR of less than 60 and 300 (56%) patients had a GFR of less than 90. An abnormal cardiac evaluation was found in 64 (12%) patients, of whom 31 (49%) had some renal impairment. The odds ratio of an abnormal cardiac evaluation with a GFR of less than 90 is 1.65 (95% confidence interval, 0.95-2.88) and 1.65 (95% confidence interval, 0.83-3.28) for GFR less than 60.

Conclusions

Renal dysfunction is common in OU patients. In these patients, renal dysfunction did not confer higher risk for abnormal cardiac evaluation.     

Life is lived forwards and understood backwards – Experiences of being affected by acute coronary syndrome: A narrative analysis

Background

Patients affected by acute coronary syndrome (ACS) report several symptoms subsequent to their discharge from hospital. These symptoms prolong their sick leave and complicate their return to the normal activities of everyday life. To improve health outcomes and establish quicker recovery for these patients, there is a need to better understand patients’ perceptions of their illness.

Objective

To explore patients’ experiences of ACS during their hospital stay.

Design

A qualitative interpretative interview study was conducted among patients during their hospitalization for ACS.

Setting

The study was performed in two designated coronary care units at a hospital in Sweden.

Participants

Twelve participants (five women and seven men; age range, 45–72 years), hospitalized with a diagnosis of ACS, were included in this study.

Methods

Patient narratives were recorded and transcribed. The records were later analyzed using a phenomenological hermeneutic approach.

Results

Patient experiences of ACS were formulated into one main theme: “awareness that life is lived forwards and understood backwards”. Two minor themes predominated in this main theme. The first was a sense of “struggling to manage the acute overwhelming phase”, which included four sub-themes: onset of life-threatening symptoms; fear and anxiety; being taken by surprise; and experiencing life as a hazardous adventure. The second theme was “striving to obtain a sense of inner security”, which also included four sub-themes: searching for and processing the cause and its explanation; maintaining a personal explanation; dealing with concern and uncertainty; and having a readiness to negotiate with life-pattern activities.

Conclusions

Hospitalized patients affected by ACS consider the cause of the onset and prepare to optimize their future health. These patients construct personal models to explain their disease, which may persist throughout continuum of care. One way to improve health outcomes for patients with ACS is to establish a shared knowledge about the illness and formulate personal care plans that cover the hospital stay as well as possibly extending into primary care after discharge, based on the patients’ point of view.     

The new Vancouver Chest Pain Rule using troponin as the only biomarker: an external validation study

Objectives

To externally evaluate the accuracy of the new Vancouver Chest Pain Rule and to assess the diagnostic accuracy using either sensitive or highly sensitive troponin assays.

Methods

Prospectively collected data from 2 emergency departments (EDs) in Australia and New Zealand were analysed. Based on the new Vancouver Chest Pain Rule, low-risk patients were identified using electrocardiogram results, cardiac history, nitrate use, age, pain characteristics and troponin results at 2 hours after presentation. The primary outcome was 30-day diagnosis of acute coronary syndrome (ACS), including acute myocardial infarction, and unstable angina. Sensitivity, specificity, positive predictive values and negative predictive values were calculated to assess the accuracy of the new Vancouver Chest Pain Rule using either sensitive or highly sensitive troponin assay results.

Results

Of the 1635 patients, 20.4% had an ACS diagnosis at 30 days. Using the highly sensitive troponin assay, 212 (13.0%) patients were eligible for early discharge with 3 patients (1.4%) diagnosed with ACS. Sensitivity was 99.1% (95% CI 97.4-99.7), specificity was 16.1 (95% CI 14.2-18.2), positive predictive values was 23.3 (95% CI 21.1-25.5) and negative predictive values was 98.6 (95% CI 95.9-99.5). The diagnostic accuracy of the rule was similar using the sensitive troponin assay.

Conclusions

The new Vancouver Chest Pain Rule should be used for the identification of low risk patients presenting to EDs with symptoms of possible ACS, and will reduce the proportion of patients requiring lengthy assessment; however we recommend further outpatient investigation for coronary artery disease in patients identified as low risk.     

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.     

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.     

Emergency Department Cardiopulmonary Evaluation of Low-Risk Chest Pain Patients with Self-Reported Stress and Anxiety

Background

Chest pain is a high-risk emergency department (ED) chief complaint; the majority of clinical resources are directed toward detecting and treating cardiopulmonary emergencies. However, at follow-up, 80%–95% of these patients have only a symptom-based diagnosis; a large number have undiagnosed anxiety disorders.

A Depressed Post-Menopausal Woman

Background

Post-menopausal women are at significant risk for coronary artery disease, have increased rates of depression compared to their male counterparts, and often present atypically with coronary insufficiency. The symptoms of depression and coronary ischemia overlap greatly. Complaints like fatigue, body aches, and sleep disturbance reported by a depressed elderly woman may be cardiac related and need to be investigated seriously without physician bias.

Objectives

To ensure that clinicians are cautious when evaluating older women with a history of depression who are presenting with atypical complaints.

Case Report

A 61-year-old woman with history of depression presented to the Emergency Department with multiple complaints atypical for acute coronary syndrome. She had an immediate electrocardiogram and troponin-T Biosite point-of-care test (Biosite Incorporated, San Diego, CA) performed, which were positive for cardiac ischemia and myocardial infarction. The patient underwent immediate cardiac catheterization, which revealed occlusion of the mid left circumflex. After aspiration of thrombus and balloon dilatation of the site, a bare metal stent was deployed, restoring excellent flow. The patient did well medically but her depression worsened after the procedure and continues despite psychiatric intervention.

Conclusion

For years there have been gender differences in medical treatment of coronary artery disease, and often women’s complaints are not investigated aggressively. Post-menopausal women are at great risk for cardiac ischemia and depression, and their symptoms, which are often atypical, may not be diagnosed as anginal equivalents. In addition, depression is an independent risk factor for cardiovascular disease and, if it occurs after myocardial infarction, may lead to poor quality of life and increased morbidity and mortality. Patients who have had a coronary event must be thoroughly evaluated for signs of depression and receive the necessary treatment.     

Prehospital Electrocardiographic Manifestations of Acute Myocardial Ischemia Independently Predict Adverse Hospital Outcomes

Background

Prehospital electrocardiography (PH ECG) is becoming the standard of care for patients activating Emergency Medical Services for symptoms of acute coronary syndrome (ACS). Little is known about the prognostic value of ischemia found on PH ECG.

Objective

The purpose of this study was to determine whether manifestations of acute myocardial ischemia on PH ECG are predictive of adverse hospital outcomes.

Methods

This study was a retrospective analysis of all PH ECGs recorded in 630 patients who called 911 for symptoms of ACS and were enrolled in a prospective clinical trial. ST-segment monitoring software was added to the PH ECG device with automatic storage and transmission of ECGs to the destination Emergency Department. Patient medical records were reviewed for adverse hospital outcomes.

Results

In 630 patients who called 911 for ACS symptoms, 270 (42.9%) had PH ECG evidence of ischemia. Overall, 37% of patients with PH ECG ischemia had adverse hospital outcomes compared with 27% of patients without PH ECG ischemia (p < 0.05). Those with PH ECG ischemia were 1.55 times more likely to have adverse hospital outcomes than those without PH ECG ischemia (95% CI 1.09–2.21; p < 0.05), after controlling for other predictors of adverse hospital outcomes (i.e., age, sex, and medical history).

Conclusions

Evidence of ischemia on PH ECG is an independent predictor of adverse hospital outcomes. ST-segment monitoring in the prehospital setting can identify high-risk patients with symptoms of ACS and provide important prognostic information at presentation to the Emergency Department.