What is the appropriate initial evaluation and management for a patient presenting with chest pain?

Immediate Evaluation and Management of Chest Pain

First 10 Minutes: Life-Threatening Exclusion Protocol

Obtain a 12-lead ECG within 10 minutes of presentation and draw high-sensitivity cardiac troponin immediately—these two tests are mandatory for every patient with chest pain, regardless of how benign the presentation appears. 1, 2, 3

The six conditions that can kill within minutes to hours must be systematically excluded:

• Acute coronary syndrome (ACS): Retrosternal pressure, squeezing, or heaviness building over minutes (not instantaneous), often radiating to left arm, neck, or jaw, with diaphoresis, dyspnea, or nausea 1, 2
• Aortic dissection: Sudden "ripping" or "tearing" chest/back pain maximal at onset; check blood pressure in both arms for >20 mmHg difference and assess all four extremities for pulse differentials 1, 2
• Pulmonary embolism: Sudden dyspnea with pleuritic chest pain worsening on inspiration; tachycardia present in >90% 1, 2
• Tension pneumothorax: Unilateral absent breath sounds, tracheal deviation, hypotension 1, 2
• Cardiac tamponade: Pleuritic pain worse supine, jugular venous distension, hemodynamic compromise 1, 2
• Esophageal rupture: History of forceful vomiting preceding pain, subcutaneous emphysema 1

Critical Physical Examination Findings

Perform a focused cardiovascular exam looking for these high-risk features:

• Hemodynamic instability: Systolic BP <100 mmHg, heart rate >100 or <50 bpm 1
• Heart failure signs: Crackles, S3 gallop, elevated jugular venous pressure 1, 2
• New murmurs: Mitral regurgitation (papillary muscle dysfunction) or aortic regurgitation (dissection) 1
• Pulse/pressure differentials: Assess all four extremities—present in ~30% of aortic dissections 1

A completely normal physical examination does NOT exclude acute myocardial infarction—uncomplicated MI frequently presents with unremarkable findings. 1

ECG Interpretation Algorithm

• ST-elevation ≥1 mm in contiguous leads (STEMI): Activate reperfusion protocol immediately—door-to-balloon <90 minutes for primary PCI or door-to-needle <30 minutes for fibrinolysis 1, 2, 3
• ST-depression or new T-wave inversions (NSTE-ACS): Admit to coronary care unit, continuous monitoring, dual antiplatelet therapy, anticoagulation, urgent angiography 1, 2
• Diffuse ST-elevation with PR-depression: Consider acute pericarditis 1, 2
• Normal or nondiagnostic ECG with persistent symptoms: Obtain serial ECGs every 15–30 minutes and add posterior leads V7–V9 1, 2

Critical pitfall: 30–40% of acute myocardial infarctions present with a normal or nondiagnostic initial ECG—never rely on a single normal ECG to exclude ACS. 1, 2

Troponin Strategy

• High-sensitivity troponin is the preferred biomarker—measure immediately on arrival 1, 2, 3
• Repeat at 1–3 hours (high-sensitivity assay) or 3–6 hours (conventional assay) after initial draw 1, 2
• Single-sample rule-out: Only acceptable if symptom onset ≥3 hours before presentation, normal ECG, and hs-troponin below limit of detection 1, 2
• Never discharge based on a single troponin drawn <6 hours from symptom onset 2

Pre-Hospital and Transport Decisions

Activate EMS immediately for any suspected life-threatening cause—do not transport by personal automobile. 1, 3

• Give chewed aspirin 162–325 mg unless known allergy or active GI bleeding 1, 4
• Sublingual nitroglycerin only if systolic BP ≥90 mmHg and heart rate 50–100 bpm 1, 4
• Intravenous morphine 4–8 mg (repeat 2 mg every 5 minutes) for pain relief—pain increases sympathetic drive and myocardial workload 1
• Oxygen 2–4 L/min only if breathless, heart failure features, or low oxygen saturation—routine oxygen in normoxemic patients may be harmful 1

Do not delay EMS transport for troponin testing in office settings when ACS is suspected—immediate transfer is essential. 1, 2, 3

Special Population Considerations

Women

• Higher risk of underdiagnosis—more frequently present with jaw/neck pain, nausea, fatigue, dyspnea, epigastric discomfort rather than classic chest pain 1, 2
• Use sex-specific troponin thresholds: >16 ng/L for women vs >34 ng/L for men—this reclassifies ~30% of women as having STEMI who would be missed with universal cutoffs 1
• Chest pain is still the dominant symptom in 87–92% of women with ACS—accompanying symptoms are additive, not replacements 1

Older Adults (≥75 years)

• Atypical presentations are common: Isolated dyspnea, syncope, acute delirium, or unexplained falls without classic chest pain 1, 2, 3
• Maintain high index of suspicion even without typical anginal symptoms 1

Risk Stratification and Disposition

High-risk features mandating immediate coronary care unit admission:

• Ongoing rest pain >20 minutes 1
• Hemodynamic instability (SBP <100 mmHg, HR >100 or <50 bpm) 1
• Troponin above 99th percentile 1
• Evidence of left ventricular failure (crackles, S3, new murmurs) 1

Low-risk criteria for chest pain unit observation (10–12 hours) or early discharge:

• Normal or nondiagnostic ECG 1, 2
• Negative troponin at presentation and 6–12 hours after symptom onset 1, 2
• Stable vital signs, no ongoing pain, no heart failure signs 1

Critical Terminology and Pitfalls

• Abandon the term "atypical chest pain"—describe as "cardiac," "possibly cardiac," or "non-cardiac" to prevent misinterpretation as benign 1, 2, 3
• Do not rely on nitroglycerin response to differentiate cardiac from non-cardiac pain—esophageal spasm also responds 1, 2, 4
• Sharp, pleuritic pain does NOT exclude ACS—approximately 13% of patients with pleuritic pain have myocardial ischemia 1
• Young age does not exclude ACS—can occur in adolescents without traditional risk factors 1