What is the initial management of a patient presenting with chest pain?

Initial Management of Chest Pain

Obtain a 12-lead ECG within 10 minutes of patient contact and immediately administer aspirin 160-325 mg (chewed) unless contraindicated, while simultaneously assessing vital signs and stabilizing the patient. 1, 2, 3

Immediate Actions (First 5-10 Minutes)

ECG Acquisition and Interpretation

• Record and interpret a 12-lead ECG within 5-10 minutes of first patient contact in any setting where cardiac origin is suspected 4, 1, 3
• If ST-segment elevation ≥1 mm in contiguous leads is present, immediately activate STEMI protocols with door-to-balloon time <90 minutes (preferred) or door-to-needle time <30 minutes for thrombolysis 4, 3
• Consider supplemental leads V7-V9 if initial ECG is nondiagnostic but clinical suspicion remains high, to detect posterior myocardial infarction 1, 3
• Perform serial ECGs if initial tracing is nondiagnostic, especially when symptoms persist or clinical condition deteriorates 1

Immediate Pharmacotherapy

• Administer aspirin 160-325 mg (chewed, not swallowed) immediately unless contraindicated by known allergy or active gastrointestinal bleeding 4, 1, 2, 3
• Provide pain relief with intravenous morphine, titrated to pain severity, as pain causes sympathetic activation and increased myocardial oxygen demand 4, 2
• Give sublingual nitroglycerin unless systolic blood pressure <90 mmHg or heart rate <50 or >100 bpm, to decrease ischemia and reduce cardiac filling pressures 4, 2, 5
• Consider beta-blockers intravenously if myocardial ischemia is suspected, particularly with tachycardia and hypertension 4

Vital Signs and Stabilization

• Check consciousness, respiration, blood pressure, heart rate, body temperature, and look for diaphoresis 4
• Establish intravenous access whenever possible 4
• Initiate continuous cardiac monitoring for arrhythmias to facilitate rapid defibrillation if needed 4, 2

Laboratory Testing

• Measure high-sensitivity cardiac troponin (hs-cTn) as soon as possible after presentation in all patients with suspected ACS 1, 2, 3
• Repeat troponin measurement at 6-12 hours after initial presentation for risk stratification 1, 2
• Draw blood samples for hemoglobin, CRP, CK, CK-MB, creatinine, and other routine labs 4, 1
• Do not delay transfer to the emergency department for troponin testing in office settings when ACS is suspected 1, 2, 3

Initial Imaging

• Obtain chest X-ray to evaluate alternative cardiac, pulmonary, and thoracic causes including pneumonia, pneumothorax, widened mediastinum, and heart failure 4, 1
• Consider transthoracic echocardiography if hemodynamic disturbances or new murmurs are found 4
• Consider transesophageal echocardiography, CT, or MR scan if aortic dissection is suspected 4

Risk Stratification and Disposition

High-Risk Features Requiring Immediate CCU Admission

• Prolonged ongoing rest pain (>20 minutes) 2, 3
• Hemodynamic instability 2, 3
• Elevated troponin above 99th percentile 2, 3
• ST-segment elevation or depression on ECG 4, 1
• Recurrent ischemia, major arrhythmias (ventricular tachycardia, complete heart block), or signs of acute heart failure (crackles, S3 gallop) 3

Reperfusion Decision Algorithm

• If ST-elevation is present: immediate reperfusion with primary PCI (door-to-balloon <90 minutes preferred) or fibrinolytic therapy (door-to-needle <30 minutes) 4, 2, 3
• If ST-depression or positive troponin without ST-elevation: admit to coronary care unit with continuous monitoring and initiate antithrombins (low-molecular-weight heparin or unfractionated heparin) 4, 1, 2
• If normal ECG but severe chest pain: perform careful history, clinical examination, and additional laboratory tests to rule out pulmonary embolism, aortic dissection, acute pericarditis, and pneumothorax 4

Patients Without High-Risk Features

• Observe in chest pain unit or emergency department for 10-12 hours after symptom onset 4
• Perform serial ECGs and troponin measurements 1
• Consider stress testing before discharge to reveal possible severe myocardial ischemia at low workload 4

Transport Decisions

• Transport patients with clinical evidence of ACS or life-threatening chest pain urgently to the emergency department by EMS rather than private vehicle 1, 3
• Pre-hospital ECG acquisition and aspirin administration by trained EMS personnel reduces mortality and in-hospital delay time 4, 3
• Never delay transfer for troponin or other diagnostic testing in office settings 1, 2

Special Population Considerations

• Women are at risk for underdiagnosis of ACS and may present with atypical symptoms including isolated dyspnea, nausea, fatigue, arm pain, jaw pain, or epigastric discomfort without classic chest pain 2, 3
• Older adults (≥75 years) may present with atypical symptoms such as isolated dyspnea, syncope, acute delirium, or unexplained falls without classic chest pain 2, 3

Critical Pitfalls to Avoid

• Do not rely on nitroglycerin response as a diagnostic tool for ACS, as esophageal spasm and other conditions may also respond 2
• Do not assume young age excludes ACS, as it can occur in adolescents without risk factors 2
• Physical examination contributes minimally to diagnosing myocardial infarction unless shock is present 2, 3
• Sharp, pleuritic pain does not exclude ACS, as pericarditis and atypical presentations can occur 2
• Total CK alone is neither sensitive nor specific enough to diagnose or exclude acute myocardial infarction 2