Clinical policy: indications for reperfusion therapy in emergency department patients with suspected acute myocardial infarction. American College of Emergency Physicians Clinical Policies Subcommittee (Writing Committee) on Reperfusion Therapy in Emergency Department Patients with Suspected Acute Myocardial Infarction

A retrospective external validation study of the HEART score among patients presenting to the emergency department with chest pain

Emergency physicians must be able to effectively prognosticate outcomes for patients presenting to the Emergency Department (ED) with chest pain. The HEART score offers a prognostication tool, but external validation studies are limited. We conducted an external retrospective validation study of the HEART score among ED patients presenting to our ED with chest pain from 1 January 2014 to 9 June 2014. We utilized chart review methodology to abstract data from each patient's electronic medical record. We collected data relevant to each of the five elements of the HEART score: history, electrocardiogram (ECG) interpretation, patient age, patient risk factors, and troponin levels. We calculated the diagnostic accuracy of the HEART score (0-10) for predicting the primary outcome of major adverse cardiac events (MACE) over 6 weeks following the ED visit (coronary revascularization, myocardial infarction, or mortality). We randomly selected 10% of patient charts from which a second investigator abstracted all data to assess inter-rater reliability for all study variables. Of 625 charts reviewed, we abstracted data on 417 (66.7%) consecutive patients meeting study inclusion criteria. Thirty-one (7.4%) of these patients experienced 6-week MACE. We observed no instances of MACE within 6 weeks among subjects with a HEART score of 3 or less. The area under the receiver operator curve (AUROC) is 0.885 (95% confidence interval 0.838-0.931). Patients with a HEART score ≤3 are at low risk for 6-week MACE. Hence, these patients may be candidates for outpatient follow-up instead of inpatient admission for cardiac risk stratification.

Isolated Posterior Acute Myocardial Infarction Presenting to an Emergency Department: Diagnosis and Emergent Fibrinolytic Therapy

Objectives

Isolated posterior acute myocardial infarction (AMI) is rare and possibly underdiagnosed. The incidence of misdiagnosis in the emergency department (ED) is unknown. Delayed diagnosis may prevent timely treatment, particularly emergent fibrinolytic therapy. We describe the experience of an urban ED on this rare condition.

Methodology

A six years and seven months case series of isolated posterior AMI of initial presentation (as identified by inpatient discharge/death ICD-9-CM diagnosis code) was studied. Patients not admitted from the ED, those who developed isolated posterior AMI only after admission and/or those with concomitant ST segment elevation AMI involving other anatomical locations of the heart (e.g. inferior or lateral walls), were excluded.

Results

Eleven cases were included in the study. All the nine cases with electrocardiograms available for review demonstrated features consistent with isolated posterior AMI. Eight out of the eleven (72.7%) cases were correctly diagnosed as isolated posterior AMI in the ED. The other three cases were treated as non-ST elevation myocardial infarction (NSTEMI). Nevertheless, their lack of the typical symptoms of acute coronary syndrome and delayed presentation (more than 12 hours) precluded them from fibrinolytics. Three of the eleven cases received fibrinolytics (all streptokinase). All three cases survived to discharge and there were no haemorrhagic complications. None of the cases underwent emergent percutaneous coronary intervention.

Conclusion

The majority of cases with isolated posterior AMI (72.7%) were diagnosed in the ED. Although three cases were interpreted as NSTEMI, the use of fibrinolytic reperfusion therapy was not affected.

Takotsubo Cardiomyopathy Presenting as Wellens' Syndrome

Takotsubo cardiomyopathy, also known as apical ballooning syndrome and stress cardiomyopathy, is a transient systolic and diastolic left ventricular dysfunction with a variety of cardiac wall-motion abnormalities that is increasingly being associated with significant morbidity and mortality. Wellens’ syndrome is an electrocardiographic (ECG) pattern in a pain-free patient that is indicative of critical occlusion of the left anterior descending coronary artery requiring immediate cardiac catheterization. The authors report a case of a patient presenting with ECG findings consistent with Wellens’ syndrome that was later found to have Takotsubo cardiomyopathy with angiographically normal coronary arteries on cardiac catheterization after a seizure.

Significance of an isolated new right bundle branch block in a patient with chest pain

Chest pain is a common presenting symptom in emergency departments, and a typical manifestation of acute myocardial infarction (AMI). Recognition of ECG changes in AMI is essential for timely diagnosis and treatment. Right bundle branch block (RBBB) may be an isolated sign of AMI, and was previously considered as a criterion for fibrinolytic therapy. Since the most recent European Society of Cardiology and American Heart Association guidelines in 2013, RBBB alone is no longer considered a diagnostic criterion of AMI, even if it occurs in the context of acute chest pain, as RBBB does not usually interfere with the interpretation of ST-segment alteration. Our case illustrates an acute septal myocardial infarction with an isolated RBBB, and thus the importance of recognising this pattern in order to permit timely diagnosis and treatment.

Chief complaint-based performance measures: a new focus for acute care quality measurement

Performance measures are increasingly important to guide meaningful quality improvement efforts and value-based reimbursement. Populations included in most current hospital performance measures are defined by recorded diagnoses using International Classification of Diseases, Ninth Revision codes in administrative claims data. Although the diagnosis-centric approach allows the assessment of disease-specific quality, it fails to measure one of the primary functions of emergency department (ED) care, which involves diagnosing, risk stratifying, and treating patients' potentially life-threatening conditions according to symptoms (ie, chief complaints). In this article, we propose chief complaint-based quality measures as a means to enhance the evaluation of quality and value in emergency care. We discuss the potential benefits of chief complaint-based measures, describe opportunities to mitigate challenges, propose an example measure set, and present several recommendations to advance this paradigm in ED-based performance measurement.

Appropriate cardiac cath lab activation: optimizing electrocardiogram interpretation and clinical decision-making for acute ST-elevation myocardial infarction

During the last few decades, acute ST-elevation on an electrocardiogram (ECG) in the proper clinical context has been a reliable surrogate marker of acute coronary occlusion requiring primary percutaneous coronary intervention (PPCI). In 2004, the American College of Cardiology/American Heart Association ST-elevation myocardial infarction (STEMI) guidelines specified ECG criteria that warrant immediate angiography in patients who are candidates for primary PPCI, but new findings have emerged that suggest a reappraisal is warranted. Furthermore, as part of integrated and efficient STEMI systems, emergency department and emergency medical services providers are now encouraged to routinely make the time-sensitive diagnosis of STEMI and promptly activate the cardiac catheterization laboratory (Cath Lab) team. Our primary objective is to provide a practical summary of updated ECG criteria for emergency coronary angiography with planned PPCI, thus allowing clinicians to maximize the rate of appropriate Cath Lab activation and minimize the rate of inappropriate Cath Lab activation. We review the evidence for ECG interpretation strategies that either increase diagnostic specificity for "classic" STEMI and left bundle-branch block or improve diagnostic sensitivity in identifying 4 STEMI-equivalents: posterior MI, acute left main occlusion, de Winter ST/T-wave complex, and certain scenarios of resuscitated cardiac arrest.

Utilization of ST-segment deviation sum and change scores to identify acute myocardial infarction

OBJECTIVE

No information is currently available regarding the optimal cutoff values of the baseline ST-segment deviation sum (STDsum(baseline)) and 60-minute ST-segment deviation change (STDchange(60 min)) for predicting acute myocardial infarction (AMI).

METHODS

A retrospective study was performed in 783 admitted patients with chest pain who had suspected acute coronary syndrome and absence of left ventricular hypertrophy or bundle branch block on the initial electrocardiogram (ECG). The STDsum(baseline) was defined as the sum in millimeters (1 mm = 0.1 mV) of the absolute value of ST-segment deviations in all 12 leads at the initiation of continuous 12-lead ECG monitoring session. The STDchange(60 min) was defined as the absolute value of the difference between the baseline and 60-minute STDsum. Three cutoff values are reported and represent the smallest values in which the positive likelihood ratio (+LR) for AMI was greater than or equal to 5, 10, and 20, respectively.

RESULTS

Acute myocardial infarction occurred in 162 (20.7%) patients. The smallest cutoff value of the STDsum(baseline) for AMI with a +LR equal to or greater than 5, 10, and 20 was 9.6, 12.4, and 14.1 mm, respectively. In the subset of 699 patients without ST-segment elevation AMI on initial ECG, the smallest cutoff value of the STDchange(60 min) for AMI with a +LR equal to or greater than 5, 10, and 20 was 2.4, 3.5, and 7.9 mm, respectively.

CONCLUSIONS

Clinical studies need to be performed to determine if STDsum and STDchange, in conjunction with physician pretest probability of AMI, can be used to select patients who may benefit from emergent reperfusion therapy and other aggressive medical management strategies.

Therapy for ST-segment elevation myocardial infarction patients who present late or are ineligible for reperfusion therapy

Despite the wide contemporary availability of pharmacological and mechanical means of reperfusion, a very significant proportion of ST-segment elevation myocardial infarction (STEMI) patients are still not offered any reperfusion therapy, and some of them are considered "ineligible for reperfusion." Spontaneous reperfusion and contraindications to the use of fibrinolytics and/or mechanical reperfusion methods account only for a small part of these clinical situations. The boundary between "timely" and "late" presentation in STEMI, the appropriateness of percutaneous intervention in patients presenting late after onset of symptoms, and the impact of sex and age on the eligibility and/or choice of reperfusion therapy continue to be challenged by the most recent published data. In the current invasive-driven reperfusion era, if scientific evidence and clinical guidelines are applied diligently, the vast majority of eligible STEMI patients should receive reperfusion therapy. Pharmacological nonlytic therapy of patients with STEMI, regardless of the choice of reperfusion strategy or the absence of it, is clearly defined by the current practice guidelines. Available data suggest that for patients who do not receive any form of reperfusion, anticoagulation therapy with low molecular weight heparin provides a clear additional mortality benefit versus placebo. Fondaparinux as compared with usual care (unfractionated heparin infusion or placebo) significantly reduces the composite of death or myocardial reinfarction without increasing severe bleeding or number of strokes. In the treatment of late-presenting patients with STEMI (beyond the first 12 h after onset of symptoms), clinical evaluation and risk stratification represent the crucial elements helping in decision making between therapeutic interventions.

An emergency physician activated protocol, 'Code STEMI' reduces door-to-balloon time and length of stay of patients presenting with ST-segment elevation myocardial infarction

INTRODUCTION

National consensus guidelines recommend that ST-segment elevation myocardial infarction (STEMI) patients achieve a door-to-balloon time of < 90 min. We sought to determine if emergency physician initiated simultaneous activation of the cardiac catheterisation laboratory team and the on-call interventional cardiologist has any impact on reducing door-to-balloon-times at our hospital.

METHODS

A total of 72 consecutive STEMI patients were evaluated from January 2007 to December 2007. The emergency physician activated Code STEMI required concurrent activation of cardiac catheterisation personnel and the on-call interventional cardiologist by the emergency physician. These patients were compared with our staff cardiologist activated primary angioplasty protocol from January 2006 to December 2006 for 51 consecutive STEMI patients. The primary outcome was to measure median door-to-balloon time between both groups. Secondary end-points included the individual components of door-to-balloon times (i.e. door-to-ECG time), peak troponin-I level within 24 h, length of stay and all-cause in-hospital mortality.

RESULTS

Median door-to-balloon time decreased overall (112 vs. 74 min, p < 0.001). Of the three components of door-to-balloon time analysed, the ECG to cardiac catheterization laboratory time exhibited the largest area of improvement with 16 min absolute reduction in median door-to-balloon time. Median peak troponin levels (50 vs. 25 ng/ml, p < 0.001), and hospital length of stay (4 vs. 3 days, p < 0.01) decreased. We did not see any statistically significant difference in all-cause in-hospital mortality (p = 0.6).

CONCLUSIONS

Emergency physician activation of the Code STEMI significantly reduces door-to-balloon time to within national standards of care, and length of stay in STEMI patients.

Emergency Physician Discretion to Activate the Cardiac Catheterization Team Decreases Door-to-Balloon Time for Acute ST-Elevation Myocardial Infarction

STUDY OBJECTIVE

The national standard for door-to-balloon time is 90 minutes, as recommended by the American Heart Association/American College of Cardiology guidelines for ST-elevation myocardial infarction (STEMI). Percutaneous coronary intervention for STEMI was initiated at our institution in June 2004. Review of our door-to-balloon times revealed that we were not meeting this recommendation. We determine whether concurrent rather than serial activation of the cardiac catheterization personnel and interventional cardiologist by the emergency physician would improve door-to-balloon times in the community hospital setting.

METHODS

We conducted a retrospective before-and-after study from June 2004 to June 2005 to evaluate this protocol change. In November 2004, a revised STEMI protocol went into effect at our community hospital that called for concurrent activation of the cardiac catheterization personnel and the interventional cardiologist by the emergency physician. No other changes were made to our protocol or personnel during this time. The mean door-to-balloon time for the 6 months before our intervention was then compared to the mean door-to-balloon time for the following 6 months.

RESULTS

During the 6-month period before protocol revision, the average door-to-balloon time for the 37 STEMI patients was 147 minutes. After the protocol was revised, the average door-to-balloon time for the 51 patients in the concurrent activation group was 106 minutes, a decrease of 41 minutes (95% confidence interval 21 to 61 minutes).

CONCLUSION

At our community hospital, concurrent activation of the cardiac catheterization team and the interventional cardiologist by the emergency physician significantly decreases door-to-balloon time for acute STEMI.

Regulatory changes for the treatment of patients with heart attacks

This editorial discusses the urgent need to reform the regulatory system that currently impedes treatment for patients with heart attacks. Existing regulations and practices often direct ambulances carrying patients with heart attacks to under-equipped facilities, and the absence of necessary advertising guidelines results in hospitals without the latest lifesaving technologies intentionally misdirecting patients to their facilities through misleading marketing. As a result, patients die needlessly. Two congressional responses are recommended in this editorial to address this national public health crisis. First, Congress should enact legislation similar to that which it created for trauma care, resulting in patients in need of critical cardiac care being directed to the most appropriate, not merely the closest, facility. Second, Congress should enact legislation that would make Medicare participation conditional on hospitals' following guidelines on how they may advertise their ability to treat patients with heart attacks. In conclusion, Congress should act to save the lives of patients with heart attacks currently being lost as a consequence of regulatory and market failures.