What are the initial labs and management for a patient presenting with chest pain?

Initial Labs and Management for Chest Pain

For patients presenting with chest pain, an ECG should be acquired and reviewed for STEMI within 10 minutes of arrival, and cardiac troponin should be measured as soon as possible when ACS is suspected. 1

Initial Assessment

History

• Evaluate chest pain characteristics including:
  • Nature (retrosternal discomfort, heaviness, pressure, squeezing) 1
  • Onset and duration (gradual build vs. sudden onset) 1
  • Location and radiation (retrosternal with possible radiation to arms, jaw) 1
  • Severity (especially "worst pain of life" for aortic dissection) 1
  • Precipitating factors (exertion, emotional stress) 1
  • Relieving factors (rest, nitroglycerin) 1
  • Associated symptoms (dyspnea, diaphoresis, nausea) 1

Physical Examination

• Perform focused cardiovascular examination to aid in diagnosis of ACS or other serious causes 1
• Look for specific findings based on suspected etiology:
  • ACS: Diaphoresis, tachypnea, tachycardia, hypotension, crackles, S3, mitral regurgitation murmur 1
  • Aortic dissection: Pulse differential, signs of connective tissue disorders 1
  • Pulmonary embolism: Tachycardia, dyspnea, pain with inspiration 1
  • Pericarditis: Friction rub, fever, positional pain 1

Initial Diagnostic Testing

Essential Initial Tests

1. 12-lead ECG - Must be performed within 10 minutes of arrival 1

   • Look for ST-segment elevation, depression, T-wave inversions, or new LBBB 1
   • Consider serial ECGs if initial ECG is nondiagnostic but clinical suspicion remains high 1
   • Supplemental leads V7-V9 are reasonable to rule out posterior MI if initial ECG is nondiagnostic 1

2. Cardiac troponin - Should be measured as soon as possible in ED setting 1

   • Critical for diagnosing acute myocardial injury 1
   • Should not be delayed if ACS is suspected 1

3. Chest radiography - Useful to evaluate for cardiac, pulmonary, or thoracic causes 1

   • Can identify widened mediastinum in aortic dissection, pneumothorax, pneumonia 1

Management Algorithm

Step 1: Determine Setting and Urgency

• Office setting with stable chest pain:

  • Perform ECG if available 1
  • If ECG unavailable or concerning, refer to ED 1

• Office setting with suspected ACS or life-threatening cause:

  • Transport urgently to ED via EMS 1
  • Do not delay transfer for troponin testing 1

• ED setting with acute chest pain:

  • Obtain ECG within 10 minutes 1
  • Measure cardiac troponin as soon as possible 1

Step 2: ECG-Directed Management

• If STEMI on ECG: Treat according to STEMI guidelines 1
• If ST depression or T-wave inversions: Treat according to NSTE-ACS guidelines 1
• If nondiagnostic ECG:
  • Perform serial ECGs if symptoms persist 1
  • Consider supplemental leads V7-V9 if posterior MI suspected 1
  • Measure troponin and reassess 1

Step 3: Risk Stratification

• Use risk scores incorporating history, ECG, age, risk factors, and troponin 2
• HEART and TIMI scores provide valuable diagnostic information 2

Common Pitfalls and Caveats

• Delayed ECG interpretation: Failure to obtain and interpret ECG within 10 minutes can delay critical interventions 1
• Relying on nitroglycerin response: Relief with nitroglycerin is not necessarily diagnostic of myocardial ischemia 1
• Overlooking atypical presentations: Especially in women, elderly, and diabetic patients who may present with atypical symptoms 1, 3
• Premature exclusion of ACS: Initial history, physical examination, and ECG alone cannot reliably exclude ACS 2
• Office-based troponin testing: Delayed transfer to ED for troponin testing should be avoided in suspected ACS 1