What is the initial workup and treatment for a patient presenting with chest pain?

Initial Workup and Treatment for Chest Pain

All patients presenting with chest pain require an ECG within 10 minutes of arrival, and those with suspected acute coronary syndrome (ACS) should receive aspirin immediately while being transported to the emergency department by EMS. 1, 2

Immediate Assessment and Stabilization

Pre-Hospital/Office Setting Actions

• Activate EMS immediately for any patient with acute chest pain suggesting ACS or life-threatening conditions—do not delay for additional testing in the office 1, 2
• Administer aspirin 250-500 mg (chewable or water-soluble) as soon as possible if ACS is suspected 1, 2
• Obtain a 12-lead ECG if available within 5 minutes, but do not delay transfer if this cannot be achieved 1
• Provide pain relief with intravenous morphine titrated to severity, as pain itself causes sympathetic activation and worsens ischemia 1
• Consider sublingual nitroglycerin (one tablet every 5 minutes up to 3 doses) if no bradycardia or hypotension present 1, 2, 3
• Establish IV access and continuous cardiac monitoring during transport 1

Emergency Department Initial Actions (First 10 Minutes)

The door-to-ECG time must be ≤10 minutes and door-to-needle time for fibrinolysis must be ≤30 minutes. 1

• Obtain and interpret 12-lead ECG immediately to identify STEMI, NSTEMI, or other acute changes 1, 2
• Draw cardiac troponin as soon as possible (troponin is the most sensitive marker for myocardial injury) 1, 2
• Place on continuous cardiac monitoring with defibrillator readily available 2
• Assess vital signs including blood pressure, heart rate, respiratory rate, and oxygen saturation 1

Focused History and Physical Examination

Critical History Elements to Obtain

• Pain characteristics: exact location, radiation pattern (left arm, jaw, back), quality (pressure, squeezing, burning), severity (0-10 scale), onset (sudden vs gradual), and duration 1, 4, 2
• Temporal features: time of onset, progression, whether pain is constant or intermittent 4, 2
• Aggravating factors: exertion, emotional stress, deep breathing, position changes, meals 1, 4
• Relieving factors: rest, nitroglycerin, antacids, position changes (note: nitroglycerin response should NOT be used diagnostically as other conditions may respond similarly) 2
• Associated symptoms: diaphoresis, nausea, vomiting, dyspnea, palpitations, syncope, fever 1, 4, 2
• Cardiovascular risk factors: hypertension, diabetes, hyperlipidemia, smoking, family history of premature coronary disease 2
• Past medical history: known coronary disease, prior MI, revascularization procedures, cardiac conditions 4, 2

Critical pitfall: Women, elderly patients, and diabetics frequently present with atypical symptoms including isolated dyspnea, nausea, or vague discomfort without classic chest pain 2

Physical Examination Priorities

• Hemodynamic assessment: hypotension, tachycardia, or bradycardia suggesting cardiogenic shock or high-grade AV block 1
• Signs of heart failure: jugular venous distension, pulmonary rales, S3 gallop, peripheral edema 1
• Cardiac auscultation: new murmurs (suggesting acute mitral regurgitation, ventricular septal defect, or pericardial friction rub) 1
• Peripheral perfusion: cool extremities, delayed capillary refill suggesting shock 1

Important caveat: Physical examination contributes minimally to diagnosing MI unless shock is present 2

ECG Interpretation and Serial Monitoring

Initial ECG Findings and Actions

• ST-elevation or new left bundle branch block: Treat as STEMI with immediate reperfusion therapy (fibrinolysis within 30 minutes or primary PCI) 1, 2
• ST-depression or T-wave inversions: Manage as NSTE-ACS per guidelines 1, 2
• Nondiagnostic or normal ECG: Does NOT exclude ACS—up to 6% of patients with evolving ACS have normal initial ECG 1

Serial ECG Strategy

If initial ECG is nondiagnostic but clinical suspicion remains high, obtain serial ECGs every 15-30 minutes or with any symptom recurrence. 1, 2

• Consider supplemental leads V7-V9 to detect posterior MI if initial ECG is nondiagnostic 1
• Compare with prior ECGs if available, as subtle changes may be significant 1
• Left ventricular hypertrophy, bundle branch blocks, and paced rhythms may mask ischemic changes 1

Laboratory Testing

Essential Initial Tests

• Cardiac troponin T or I: Most sensitive marker for myocardial injury; obtain at presentation and repeat at 6-12 hours if initial is negative 1, 2
• Complete blood count: Assess for anemia which may precipitate ischemia 1
• Basic metabolic panel: Evaluate electrolytes and renal function 1
• Chest radiograph: Evaluate for pneumothorax, pneumonia, pulmonary edema, aortic dissection 1, 2

Critical pitfall: Do NOT delay transfer from office setting to obtain troponin—this can be detrimental 1

Risk Stratification for ACS

High-Risk Features Requiring Immediate Intervention

Patients with any of the following require urgent coronary angiography: 1, 2

• Recurrent ischemia (ongoing chest pain or dynamic ST-segment changes)
• Elevated troponin levels
• Hemodynamic instability (hypotension, pulmonary edema)
• Major arrhythmias (ventricular tachycardia, ventricular fibrillation)
• Early post-infarction unstable angina
• Diabetes mellitus with ACS
• ECG pattern precluding ST-segment assessment (LBBB, paced rhythm)

Low-Risk Patients

• Negative serial troponins, normal or unchanged ECG, and low clinical suspicion may undergo outpatient stress testing or coronary CT angiography 1, 2, 5
• Immediate exercise testing can be performed safely in truly low-risk patients (no hemodynamic instability, arrhythmias, or ECG ischemia) to facilitate safe ED discharge 6

Initial Medical Treatment

For Suspected ACS (While Awaiting Definitive Diagnosis)

• Aspirin 162-325 mg (chewed) immediately if not already given 1, 2
• Nitroglycerin sublingual 0.4 mg every 5 minutes up to 3 doses for ongoing pain (avoid if hypotension, bradycardia, or suspected right ventricular infarction) 1, 2, 3
• Morphine 2-4 mg IV titrated for pain relief if nitroglycerin ineffective 1
• Beta-blocker (e.g., metoprolol 25-50 mg orally) for tachycardia and hypertension in absence of contraindications (heart failure, hypotension, bradycardia, reactive airway disease) 1, 7
• Anticoagulation with LMWH or unfractionated heparin for NSTE-ACS 1
• Oxygen only if hypoxemic (SpO2 <90%)—routine oxygen is not beneficial 1

Absolute contraindication: Never give nitroglycerin to patients taking PDE-5 inhibitors (sildenafil, tadalafil, vardenafil) due to severe hypotension risk 3

Differential Diagnosis Beyond ACS

Life-Threatening Causes Requiring Immediate Evaluation

• Aortic dissection: Tearing pain radiating to back, pulse differential, widened mediastinum on chest X-ray—requires CT angiography or TEE 1
• Pulmonary embolism: Sudden dyspnea with pleuritic pain, risk factors for VTE—consider D-dimer, CT pulmonary angiography 1, 4
• Tension pneumothorax: Sudden sharp pain with dyspnea, absent breath sounds, tracheal deviation—requires immediate needle decompression 1, 4
• Pericarditis with tamponade: Positional chest pain, muffled heart sounds, pulsus paradoxus—requires echocardiography 1

Common Non-Cardiac Causes

• Musculoskeletal (costochondritis): Reproducible chest wall tenderness, pain with movement 4, 5
• Gastroesophageal reflux: Burning retrosternal pain related to meals, relieved by antacids 4, 5
• Anxiety/panic disorder: Associated with hyperventilation, palpitations, sense of doom 4, 5

Disposition Decisions

• STEMI or high-risk NSTE-ACS: Immediate cardiac catheterization laboratory activation 1, 2
• Intermediate-risk ACS: Admission to monitored bed, serial troponins, cardiology consultation 1, 2
• Low-risk with negative workup: Outpatient stress testing within 72 hours or discharge with primary care follow-up 2, 5
• Non-cardiac diagnosis confirmed: Treat underlying condition appropriately 2