Table of Contents

 

Suspected acute myocardial infarction is a common presentation in the ED that requires swift mobilization of EMS and hospital resources in order to diagnose and manage a patient until definitive reperfusion therapies can be initiated.

What are the most common mimics of STEMI and what are the ECG and clinical findings that can distinguish them?

Besides chest pain, what are the other signs and symptoms of acute coronary syndromes that have a high positive predictive value for STEMI?

What are the clinical circumstances when a chest x-ray, CT, or echocardiogram might be indicated?

What are the laboratory studies that could be considered (even though none should delay cardiac catheterization laboratory activation)?

What are the recommended cut-points for leads V2 and V3, based on age and gender?

When would obtaining posterior ECG leads be indicated?

How can use of the Sgarbossa criteria reduce false activation of the cardiac catheterization laboratory?

Oxygen, opioids, aspirin, nitroglycerin, P2Y12 inhibitors, beta blockers, heparin: what are the latest recommendations on their use?

When PCI isn’t readily available, what are the agents and timing requirements for thrombolytics and ultimate transfer?

1. Abstract
2. Case Presentations
3. Introduction
4. Critical Appraisal of the Literature
5. Etiology and Pathophysiology
6. Differential Diagnosis
7. Prehospital Care
8. Emergency Department Evaluation
   1. History
   2. Physical Examination
9. Diagnostic Studies
   1. Imaging
   2. Laboratory Testing
   3. Electrocardiogram
      1. Lead aVR
      2. Posterior Leads
      3. Left Bundle Branch Block and Paced Rhythms
      4. Serial Electrocardiograms
      5. Reciprocal Changes
      6. Differentiating Pericarditis From STEMI
10. Treatment
    1. Initial Therapies
       1. Oxygen
       2. Opioids
    2. Antiplatelet Therapy
       1. Aspirin
       2. P2Y12 Inhibitors
    3. Nitroglycerin
    4. Beta Blockers
    5. Reperfusion Therapies
       1. Percutaneous Coronary Intervention
       2. Thrombolytics
       3. Reperfusion Dysrhythmias
    6. Heparin and Anticoagulation Therapy
    7. Transfer of STEMI Patients to a PCI Center
11. Special Circumstances and Populations
    1. Gender Differences
    2. Elderly Patients
    3. Cocaine-Associated STEMI
       1. Out-of-Hospital Cardiac Arrest
12. Controversies and Cutting Edge
    1. Managing STEMI During the COVID-19 Pandemic
    2. PCI for STEMI of 12- to 24-Hour Duration
    3. Transfer of STEMI Patients to a PCI Center
    4. PCI for the Elderly and Patients with Severe Comorbidities
13. Disposition
14. Risk Management Pitfalls for Patients in the Emergency Department With STEMI
15. Summary
16. Case Conclusions
17. Clinical Pathway for Management of STEMI in the Emergency Department
18. Tables and Figures
    1. Table 1. Differential Diagnosis of ST-Segment Elevation
    2. Table 2. PAILS Mnemonic for Reciprocal Changes
    3. Table 3. Findings Differentiating Pericarditis From STEMI
    4. Table 4. Agents for Fibrinolysis
    5. Table 5. Anticoagulation Therapy for STEMI Patients Receiving Fibrinolytic Therapy
    6. Figure 1. Type 1 Myocardial Infarction
    7. Figure 2. Coronary Artery Anatomy
    8. Figure 3. Predicted Distribution of ST-Segment Elevation Relative to Occluded Artery
    9. Figure 4. Electrocardiogram of ST-Segment Elevation Caused by Hyperkalemia
    10. Figure 5. Identification of the J Point
    11. Figure 6. Electrocardiogram Showing ST-Segment Elevation in aVR With Widespread ST Depressions in a Patient with a Left Main Coronary Artery Stenosis
    12. Figure 7. Posterior Lead Placement
    13. Figure 8. ECG of Posterior STEMI
    14. Figure 9. Sgarbossa Criteria
    15. Figure 10. Modified Sgarbossa Rule
    16. Figure 11. ECG of Concordant ST-Segment Elevation in Left Bundle Branch Block
    17. Figure 12. Electrocardiogram of Accelerated Idioventricular Rhythm
19. References

Abstract

ST-segment myocardial infarction (STEMI) is a time-sensitive emergency that requires swift and seamless integration of prehospital and emergency department resources in order to achieve early diagnosis and reperfusion therapy. This issue reviews the current literature on emergency department management of STEMI, including recognition of more subtle diagnoses on electrocardiogram, identification of STEMI mimics, an update on treatment therapies, and strategies to achieve more effective management of STEMI across gender and age groups.

Case Presentations

A 74-year-old woman with chest pain is delivered to your ED by EMS…

• You greet the paramedics, and they inform you that the patient called 911 from home because she was having chest pain. They have given her 324 mg of aspirin orally and 3 doses of 0.4 mg of nitroglycerin sublingually. The patient’s pain improved, but is still present.
• Her vital signs are normal. The paramedic hands you an ECG that he obtained and states that there is anterior ST-segment depression concerning for ischemia, but no ST elevation.
• You look at the tracing and note ST depression in leads V₂ and V₃. You wonder whether this could actually be a STEMI, and what would be the best way to confirm your suspicion…

A 60-year-old man presents with retrosternal chest pain…

• The patient reports that he’s had pain for 2 days that has been constant and never goes away.
• He has no dyspnea, diaphoresis, or radiation of the pain. Additionally, there is no increase in the pain with exertion.
• You obtain an ECG and note ST-segment elevation in the inferior and lateral leads.
• Given the patient’s history of present illness, you are not convinced that he has STEMI and wonder what the best next step is…

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Clinical Pathway for Management of STEMI in the Emergency Department

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Tables and Figures

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Key References

Following are the most informative references cited in this paper, as determined by the authors.

1. Thygesen K, Alpert JS, Jaffe AS, et al. Fourth universal definition of myocardial infarction (2018). Eur Heart J. 2019;40(3):237-269. (Guideline) DOI: 10.1093/eurheartj/ehy462

4. O’Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2013;127(4):e362-e425. (Evidence-based guideline) DOI: 10.1161/CIR.0b013e3182742c84

8. Anderson JL, Adams CD, Antman EM, et al. ACC/AHA 2007 guidelines for the management of patients with unstable angina/non–ST-elevation myocardial infarction. Circulation. 2007;116(7). (Guideline) DOI: 10.1161/CIRCULATIONAHA.107.181940

35. Ibanez B, James S, Agewall S, et al. 2017 ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation: the Task Force for the Management of Acute Myocardial Infarction in Patients Presenting With ST-Segment Elevation of the European Society of Cardiology (ESC). Eur Heart J. 2018;39(2):119-177. (Evidence-based guideline) DOI: 10.1093/eurheartj/ehx393

40. Tabas JA, Rodriguez RM, Seligman HK, et al. Electrocardiographic criteria for detecting acute myocardial infarction in patients with left bundle branch block: a meta-analysis. Ann Emerg Med. 2008;52(4):329-336. (Systematic review and meta-analysis; 11 studies, 2100 patients) DOI: 10.1016/j.annemergmed.2007.12.006

57. American College of Emergency Physicians Clinical Policies Subcommittee on Reperfusion Therapy for Acute STEMI, Promes SB, Glauser JM, et al. Clinical Policy: emergency department management of patients needing reperfusion therapy for acute ST-segment elevation myocardial infarction. Ann Emerg Med. 2017;70(5):724-739. (Clinical Policy) DOI: 10.1016/j.annemergmed.2017.09.035

76. Wenger N. “STEMI at Elderly Age: Expert Analysis.“ 2016. Accessed December 10, 2020. (ACC expert anaylsis)

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Keywords: STEMI, myocardial infarction, acute coronary syndromes, ACS, electrocardiogram, ECG, EMS, diaphoresis, troponin, left bundle branch block, LBBB, posterior, Inferobasal, Sgarbossa, PCI, reciprocal, oxygen, aspirin, opioids, P2Y12, nitroglycerin, thrombolytic, fibrinogen, heparin, cocaine

Points & Pearls Excerpt

• The location of the coronary occlusion will produce ST-segment elevation in a predictable pattern on ECG. (See Figure 3.)
• The goals of prehospital management of STEMI are early recognition, administration of aspirin, and timely transport to a PCI-capable facility for reperfusion.
• Patients with suspected ACS should have an ECG performed within 10 minutes of the first medical contact, and serial ECGs should be performed liberally to monitor for changes.
• Bypassing non-PCI capable facilities to get the STEMI patient to a PCI-capable facility is safe, and is recommended if the first medical contact-to-balloon time is <90 minutes and transport time is <30 minutes.¹⁷
• Echocardiography is a noninvasive way to assess for regional wall motion abnormalities or other pathologic findings, and it can help confirm a diagnosis.