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

Acute Chest Pain Evaluation

Immediate Actions (First 10 Minutes)

Obtain a 12‑lead ECG within 10 minutes of patient arrival and measure high‑sensitivity cardiac troponin immediately, regardless of age, sex, or perceived likelihood of acute coronary syndrome. 1

• Assess vital signs including heart rate, respiratory rate, oxygen saturation, and blood pressure in both arms; a systolic difference >20 mm Hg between arms suggests aortic dissection. 1
• Perform a focused cardiovascular examination for diaphoresis, tachypnea, pulmonary crackles, S3 gallop, new murmurs (especially aortic regurgitation), pericardial friction rub, unilateral absent breath sounds, pulse differentials, and jugular venous distension. 1
• If the ECG shows ST‑elevation, new left bundle‑branch block, or new ischemic changes, activate emergency medical services immediately and initiate STEMI protocols without delay. 1

Life‑Threatening Causes Requiring Urgent Exclusion

Acute Coronary Syndrome (ACS)

• Typical presentation includes retrosternal pressure, heaviness, or squeezing that builds over minutes (not seconds) and may radiate to the left arm, jaw, or neck; associated symptoms such as diaphoresis, dyspnea, nausea, or syncope markedly increase the likelihood of myocardial ischemia. 1
• Approximately 30–40% of acute myocardial infarctions present with a normal or nondiagnostic initial ECG, so serial ECGs every 15–30 minutes and repeat troponin testing are mandatory. 1
• Sharp or pleuritic chest pain does NOT exclude ACS; approximately 13% of patients with pleuritic‑type pain have acute myocardial ischemia. 1
• A completely normal physical examination does not rule out myocardial infarction; uncomplicated MI can present with entirely normal findings. 1

Aortic Dissection

• Sudden "ripping" or "tearing" chest or back pain that is maximal at onset is characteristic. 1
• Pulse differentials between extremities occur in ~30% of patients; a systolic blood‑pressure difference >20 mm Hg between arms and a new aortic‑regurgitation murmur (present in 40–75% of type A dissections) are critical physical findings. 1
• Risk factors include connective‑tissue disorders (Marfan syndrome), advanced age, hypertension, and atherosclerosis. 1

Pulmonary Embolism

• Acute dyspnea with pleuritic chest pain that worsens with inspiration is the hallmark presentation. 1
• Tachycardia occurs in >90% of patients; tachypnea (>20 breaths/min) in ~70%. 1
• Calculate Wells score or apply PERC rule to assess risk; if intermediate‑to‑high probability, proceed directly to CT pulmonary angiography. 2, 3

Tension Pneumothorax

• Dyspnea and sharp chest pain that intensifies with inspiration, accompanied by unilateral absent breath sounds, hyperresonant percussion, tracheal deviation, and hemodynamic instability. 1

Esophageal Rupture (Boerhaave Syndrome)

• Severe chest pain typically follows forceful vomiting; subcutaneous emphysema of the neck or chest and concurrent pneumothorax (~20% of cases) are key findings. 1

Cardiac Troponin Testing Strategy

• High‑sensitivity cardiac troponin is the most sensitive and specific biomarker for myocardial injury and should be drawn immediately. 1
• A single normal troponin does NOT rule out ACS; repeat measurement is required at 1–3 hours for high‑sensitivity assays or 3–6 hours for conventional assays. 1, 4
• For patients with symptom onset ≥3 hours before presentation and high‑sensitivity troponin below the limit of detection (<5 ng/L for hs‑cTnI or <6 ng/L for hs‑cTnT), a single measurement can safely rule out myocardial infarction with >99% negative predictive value. 4
• If the initial troponin is in the "observational zone" (detectable but below the 99th percentile), repeat testing is mandatory. 4

Serious Cardiac Causes (Non‑ACS)

Pericarditis

• Sharp, pleuritic chest pain that worsens when lying supine and improves when sitting or leaning forward. 1
• A pericardial friction rub may be audible (absence does not exclude disease); fever is common. 1
• ECG shows diffuse concave ST‑elevation with PR‑segment depression. 1

Myocarditis

• Chest pain accompanied by fever and signs of heart failure (S3 gallop); clinical presentation can mimic ACS, necessitating cardiac troponin measurement for differentiation. 1, 2
• Cardiac MRI with gadolinium contrast is the gold standard to distinguish myopericarditis from other causes. 2

Infective Endocarditis

• High fevers and chills are present in 80–90% of cases; fatigue and constitutional symptoms are common. 2
• Chest pain can occur through septic pulmonary emboli, coronary artery embolization, or pericardial involvement. 2
• Obtain blood cultures before antibiotics and transthoracic echocardiography to assess for vegetations. 2

Common Non‑Cardiac Causes

Costochondritis/Tietze Syndrome

• Chest wall pain reproducible with palpation of costochondral joints; pain is influenced by breathing, turning, twisting, or bending. 1
• Accounts for approximately 43% of chest‑pain presentations in primary care after cardiac causes are excluded. 1
• Critical pitfall: Up to 7% of patients with reproducible chest‑wall tenderness still have ACS; do not skip ECG and troponin testing. 1

Gastroesophageal Reflux Disease (GERD)

• Burning retrosternal pain related to meals or occurring at night; stress may exacerbate symptoms, and antacids often provide relief. 1
• Do NOT rely on nitroglycerin response to differentiate cardiac from esophageal pain because esophageal spasm may also respond. 1

Pneumonia

• Fever with localized, often pleuritic chest pain; examination may reveal regional dullness, egophony, and possibly a pleural friction rub. 1

Herpes Zoster

• Unilateral dermatomal burning or tingling pain triggered by touch, described as burning or tingling, that does not cross the midline; a vesicular rash follows the affected dermatome, often preceded by pain. 1

High‑Risk Features Requiring Immediate EMS Transport

• ST‑elevation or new ischemic changes on ECG. 1
• Hemodynamic instability (hypotension, shock). 1
• Age >75 years with accompanying dyspnea, syncope, acute delirium, or unexplained fall. 1
• Associated diaphoresis, dyspnea, nausea, or syncope. 1

Special Population Considerations

Women

• At higher risk for underdiagnosis and more often present with atypical symptoms (jaw/neck pain, nausea, fatigue, dyspnea, epigastric discomfort, back pain). 1
• Using sex‑specific high‑sensitivity troponin thresholds (>16 ng/L for women vs >34 ng/L for men) helps avoid missing ~30% of women with STEMI. 1

Older Adults (≥75 years)

• May present atypically with isolated dyspnea, syncope, acute delirium, or unexplained falls without classic chest pressure. 1

Patients with Diabetes

• Frequently have silent or atypical ischemic presentations (vague abdominal symptoms, confusion, isolated dyspnea) and carry a higher risk of silent myocardial ischemia. 1

Risk Stratification After Initial Negative Work‑Up

Low‑Risk Criteria (All Must Be Present)

• Normal or nondiagnostic ECG. 1
• Negative troponin at presentation and at repeat measurement (1–3 hours for hs‑cTn or 3–6 hours for conventional). 1, 4
• Stable vital signs. 1
• No ongoing pain. 1
• Absence of heart‑failure signs. 1

Management of Low‑Risk Patients

• Discharge with outpatient stress testing or coronary CT angiography within 72 hours for patients with cardiovascular risk factors (age ≥60 years, hypertension, hyperlipidemia, diabetes, smoking). 1, 5
• For truly low‑risk patients (<1% 30‑day risk of death or major adverse cardiovascular events), discharge without further urgent testing is reasonable. 4, 6

Critical Pitfalls to Avoid

• Do NOT dismiss ACS in women, elderly patients, or individuals with diabetes based on atypical presentations; they frequently present with non‑classic symptoms. 1
• Do NOT assume a normal physical examination excludes ACS; uncomplicated myocardial infarction can present with a completely normal exam. 1
• Do NOT rely on nitroglycerin response to differentiate cardiac from non‑cardiac chest pain, as esophageal spasm and other conditions may also respond. 1
• Do NOT discharge a patient after a single normal troponin drawn <3 hours from symptom onset; repeat testing is mandatory. 4
• Do NOT assume reproducible chest‑wall tenderness rules out ACS; approximately 7% of such patients still have acute coronary syndrome. 1