Introduction

Heart Disease is the leading cause of death in adults in the United States. Recent advances in the treatment of acute myocardial infarction have significantly reduced rates of morbidity and mortality. However, these treatments are time-sensitive and necessitate rapid initiation for desirable outcomes.

It is an essential part of the initiation process for patients to recognize signs and symptoms of ST-elevation myocardial infarction (STEMI) and seek help immediately. The healthcare provider’s role is to accurately diagnose an MI to initiate appropriate treatment, regardless of its presentation, whether typical or atypical. Initial Management of Patients with STEMI will cover timing, protocol, checklists, and more to help improve patient outcomes and reduce morbidity and mortality.

Delay in Treatment

Several concerns relate to the delay in the treatment and diagnosis of STEMI. The first area of concern is related to the delay in patient access to medical care. Many patients wait a significant amount of time after the onset of symptoms before seeking care (1).

The initial management of patients with STEMI is the most crucial part of treatment, and delays in treatment can worsen outcomes.

Timing is Everything

• The median delay from chest pain onset to critical care admission is approximately 3.5 hours.
• The average delay is significantly longer due to almost 20% of patients presenting for treatment ≤ 12 hours after the onset of symptoms (1).

Studies show that if a patient with acute myocardial infarction is treated within 90 minutes of contact time, the damage to the left ventricle can be minimized. If therapy is delivered after this amount of time, the rates of morbidity and mortality rise dramatically as irreversible damage has already occurred (2). The first step in the initial management of patients with STEMI is in the patients’ control, which is why patient education is vital to help patients recognize the symptoms.

Any patient with cardiovascular disease or risk factors for AMI should be educated on recognizing the signs and symptoms of acute coronary syndrome. Coronary ischemia or infarct manifestations may include (all from 2):

• chest or back pain may radiate down the left arm
• diaphoresis
• tachycardia
• irregular pulse
• bradycardia, if sinus node function is impaired
• unequal palpable pulses
• murmurs
• elevated blood pressure
• jugular vein distension
• wheezing or pulmonary congestion
• pulsatile abdominal mass
• pallor
• poor capillary refill

The second concern concerns delays that may occur before the healthcare provider makes an AMI  diagnosis and definitive care is implemented. Establishing a baseline with an initial EKG upon patient arrival is essential for early recognition and evaluation. Additionally, laboratory diagnostics focus on troponin elevation as a specific and reliable measurement for the accuracy of identifying AMI.

Healthcare providers must take diligence to assess chest pain and discomfort thoroughly. Chest wall tenderness is reported in up to 5% of patients presenting with an AMI, leading to a misdiagnosis of skeletal-muscular origination of the pain (2).

The third area of concern is the healthcare provider’s failure to diagnose AMI in patients with typical or atypical systems correctly. Correct diagnosis is pivotal in the initial management of patients with STEMI.

Based on research from the American College of Emergency Physicians (ACEPS), “4-13% of patients with AMI are released from the ED with false reassurance that they do not have coronary artery disease as a cause of their symptoms (2).” Many of these patients later suffer complications from their MI, with 11-25 % of these patients dying (2).

Because of these astonishing numbers and the failure of the traditional approach, many Emergency Departments have developed specialized protocols, personnel, space, and equipment for patients presenting with chest pain. Along with these protocols, 911 dispatchers and EMS providers should perform prehospital chest pain evaluations to begin the process of diagnosis and treatment promptly and improve patient outcomes.

In patients with ECG evidence of STEMI, paramedics should review a reperfusion checklist and relay ECG checklist findings to a predetermined medical facility (2). This checklist determines potential comorbidities and underlying conditions in which fibrinolytic therapy could harm the patient.

Reperfusion Checklist for Evaluation of the Patient with STEMI

The following checklist covers the process for evaluating a patient to determine if fibrinolysis is indicated in the initial management of patients with STEMI (3).

STEP 1:

Has the patient experienced chest discomfort for over 15 minutes and less than 12 hours?

• No -> STOP
• Yes -> Are there any contraindications to fibrinolysis?

STEP 2:

Are any of the following true for the patient?

• Diastolic BP > 100 mmHg
• Right vs left arm systolic BP difference greater than 15 mmHg
• History of structural central nervous system disease
• Significant closed head/facial trauma within the last three months
• Recent major trauma, surgery or GI bleed (6 weeks)
• Bleeding or clotting problem OR on blood thinners
• Pregnant female
• Serious systematic disease

If ANY are true, fibrinolysis may be contraindicated.

STEP 3:

Does the patient have severe heart failure or cardiogenic shock such that PCI is preferable?

• Pulmonary edema
• Systemic hypoperfusion

Example of Interventional Protocol from the American College of Cardiology

The American College of Cardiology has created a Door-to-Balloon “STEMI Alert” Checklist as a standard for intervention among patients experiencing STEMI. Below are steps, processes, and protocols for a patient receiving timely treatment. The door-to-balloon time goal is ≤90 minutes if patients arrive directly at the ED without EMS transport (3). The informational checklist below is based on information from the American College of Cardiology and the American Heart Association as a guideline for a STEMI patient (2,3).

Initial Patient Contact to Confirmed STEMI Diagnosis—Goal Time: 5 Minutes

If a patient arrives by ambulance:  

• ECG was obtained, and an assessment was conducted in an ambulance.
• ECG was transmitted from the ambulance to the ED, along with a physical assessment to confirm STEMI.

If a patient arrives at the hospital in a personal car or ambulance without ECG:  

• The triage nurse should perform a rapid assessment and history of pain and obtain an ECG with a patient with complaints of chest pain and less typical signs of MI.
• ECG and assessment findings are communicated to advanced providers or physicians to confirm STEMI.

For ALL patients: 

• 2L of oxygen should be administered per nasal cannula.
• Asa 81 mg. x 4 chewed and administered in an ambulance unless already taken by the patient or contraindicated.
• Consider morphine sulfate administered for pain.
• IV fluids at KVO
• Lab work including cardiac markers, CVC, INR, BMP, and Lipid Profile

STEMI Diagnosis to Initiation of Cardiac Cath Lab—Goal Time: 5 Minutes

• ED physician or advanced provider notified the hospital operator to send the group page to the Interventional Cardiologist and Cardiac Cath Lab Team.
• The Interventional Cardiologist and the Cardiac Cath lab team responded to the page within 5 minutes.
• ED physician or advanced provider verified with the hospital operator that pages are confirmed.

Activation of Cardiac Cath Lab Team to Arrival—Goal Time: 30 Minutes

• ED physician or advanced provider explained the diagnosis, coronary angiography, and PCI to the patient and family before the Interventional Cardiologist’s arrival.
• Informed consent was obtained from the patient or next of kin for diagnostic cath and PCI.
• Data collected included VS, height and weight, pulmonary assessment, cardiac auscultation, peripheral pulse assessment, time of symptom onset, allergies, prior cardiac procedure history, last meal, and description of chest discomfort.
• Heparin administered.
• Glycoprotein IIB/IIA Inhibitors were administered (block platelet aggregation).
• Beta-blockers are administered unless contraindicated.
• The admitting team was notified of critical care or step-down beds.
• The staff prepares the catheterization site.
• Staff communicate regarding transport to the cath lab.

Cardiac Cath Lab Team Arrival to Intervention—Goal Time: 35 Minutes

• Pre-mixed medications are readily accessible to the cath lab (e.g., dopamine, dobutamine, Nitroglycerine, heparin).
• The ED nurse and cath lab nurse completed the nursing hand-off.
• The family was sent to the waiting area, and the ED nurse notified pastoral care.
• Patient lab results were called to the cath lab.
• The interventional Cardiologist scrubbed in while the patient was positioned on the table.
• The nurse and tech staff position the patient on table monitors, connecting the patient to prep and drape. They provide an ongoing assessment of the patient.
• Angiography of infarct-related arteries was performed to allow the selection and preparation of interventional equipment. The guide catheter and interventional guidewire were prepped and ready for a decision to proceed with PCI (passing of the guidewire to re-establish blood flow).
• Angioplasty balloons and coronary stents were prepped and ready.
• Heparin administered.

Initial Management of Patient with STEMI Symptoms

Physical Exam

“Physical examination should be performed to aid in the diagnosis and assessment of the extent, location, and presence of complications of STEMI (2).” A brief, limited neurological exam to assess for evidence of stroke should be performed before the administration of fibrinolytic therapy (2). These exams enable rapid triage of patients to expedite the treatment process.

• Brief Physical Exam
• Airway, Breathing Circulation (ABC)
• Vital Signs
• Presence or absence of jugular venous distension
• Pulmonary auscultation
• Cardiac auscultation
• Presence or absence of stroke
• The presence or absence of pulses
• Presence or absence of systemic hypoperfusion (cool, clammy, pale, ashen)

According to the American Heart Association guidelines in treating a patient with a STEMI, the choice of STEMI treatment should be made by the emergency medicine physician or advanced practitioner on-call based on the predetermined, institution-specific protocol. The protocol should be a collaborative approach involving cardiologists, emergency physicians/practitioners, nurses, and other appropriate personnel. For patient situations where the diagnosis and treatment plan are unclear to the provider or not covered explicitly by the institution’s written protocol, immediate cardiology consultation is advisable (2).

Laboratory Findings and Biomarkers

Laboratory exams should be performed as a part of management for STEMI patients; however, the process should not delay reperfusion therapy initiation (2).

• Cardiac-specific troponins should be the ideal biomarker for evaluating patients with STEMI with coexistent skeletal muscle injury.
• For patients with ST elevation and symptoms of STEMI, reperfusion therapy should be initiated as soon as possible and should not be contingent on a biomarker assay (2).
• Serial biomarkers can provide supportive evidence of reperfusion after fibrinolytic therapy in patients not undergoing angiography within the first 24 hours after receiving it. However, they should not be relied upon to diagnose reinfarction within the first 18 hours after the onset of STEMI (2).

Nitroglycerine

Nitroglycerine is indicated for relieving ongoing ischemic discomfort, controlling hypertension, or managing pulmonary congestion (2).

• Patients with ongoing discomfort should receive sublingual nitroglycerin (0.4 mg) every 5 minutes for a total of 3 doses. After this, an assessment should be made about the need for intravenous nitroglycerine.
• Should not be administered to patients with systolic blood pressure less than 90 mmHg or greater than or equal to 30 mmHg below baseline, severe bradycardia, tachycardia, or suspected RV infarction.
• It should not be administered to patients who have received phosphodiesterase inhibitors for erectile dysfunction within the last 24 hours (2).

Pain Management

Pain management is a crucial element in the initial management of patients with STEMI. The control of cardiac pain is usually accomplished with a combination of nitrates, opiate analgesics, oxygen, and beta-adrenergic blockers.

Facts to keep in mind upon assessment of a patient presenting with possible STEMI:

• Elderly patients are more likely to complain of shortness of breath as well as other atypical symptoms such as syncope or unexplained nausea (2).
• People with diabetes may have impaired angina (pain) recognition, especially in the presence of autonomic neuropathy. Diabetic patients may misinterpret dyspnea, nausea, vomiting, fatigue, and diaphoresis as a disturbance of their diabetic control (2).
• Only 40-50% of patients with AMI have clear evidence of ECG infarction on their initial presentation to the ED (1). Therefore, protocol and observational data are extremely important tools for the response team to remember when caring for and diagnosing a patient with STEMI.
• If the initial ECG is not diagnostic of STEMI, but the patient remains symptomatic, and there is high clinical suspicion for STEMI, serial ECGs at 5–10-minute intervals or continuous 12-lead ST-segment monitoring should be performed to detect potential development of ST elevation.

Conclusion

The initial management of patients with STEMI is the most crucial part of treatment. With the implementation of quality protocols and team management, the healthcare team can evolve and implement strategies to improve patient outcomes and reduce morbidity and mortality. It is essential for healthcare providers working in Emergency Departments, Cath Labs, ICUs, and step-down units to understand the importance of timely intervention among the patients that they are caring for.