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

Initial Workup for Chest Pain

For patients presenting with chest pain, obtain an ECG within 10 minutes of arrival and measure cardiac troponin (preferably high-sensitivity) as the essential first steps in evaluation. 1, 2

Immediate Assessment

1. First 10 minutes:

   • Obtain and interpret 12-lead ECG within 10 minutes of arrival 1
   • Order cardiac troponin measurement (preferably high-sensitivity) 1, 2
   • Assess vital signs and hemodynamic stability 2
   • Provide supplemental oxygen if hypoxemic 2

2. History elements to focus on:

   • Pain characteristics (OPQRST method)
   • Associated symptoms (dyspnea, nausea, diaphoresis, syncope)
   • Risk factors (hypertension, diabetes, smoking, family history)
   • Consider atypical presentations in:
     • Women (more likely to have accompanying symptoms like nausea and shortness of breath) 1
     • Elderly patients (may present with shortness of breath, syncope, delirium, or falls) 1
     • Diabetic patients (diminished pain perception) 2

3. Physical examination:

   • Focused cardiovascular examination to identify life-threatening causes 1
   • Look for specific findings that suggest alternative diagnoses:
     • Pulse differential (aortic dissection)
     • Friction rub (pericarditis)
     • Unilateral decreased breath sounds (pneumothorax)
     • Costochondral tenderness (musculoskeletal pain)
     • Egophony/dullness to percussion (pneumonia) 1, 2

Diagnostic Testing

1. Initial tests:

   • ECG: Look for ST-segment elevation, depression, T-wave inversions, or new LBBB 1
   • Cardiac troponin: For high-sensitivity assays, repeat at 1-2 hours; for conventional assays, repeat at 3-6 hours 1
   • Consider chest X-ray if suspecting non-cardiac causes 2

2. Serial testing:

   • For patients with initially negative results but ongoing suspicion:
     • Serial ECGs to detect evolving changes 1
     • Serial troponin measurements (high-sensitivity: 0,1-2 hours; conventional: 0,3-6 hours) 1, 2

Risk Stratification

1. High-risk features (require immediate intervention):

   • STEMI or new LBBB on ECG
   • Hemodynamic instability
   • Elevated cardiac troponin
   • Ongoing severe chest pain unresponsive to nitrates
   • Signs of heart failure 2

2. Intermediate-risk features (require observation/further testing):

   • Known coronary artery disease
   • Multiple cardiovascular risk factors
   • Age >65 years
   • Non-specific ECG changes 2

3. Low-risk features (may be suitable for early discharge):

   • Young age
   • Atypical symptoms
   • Normal ECG
   • Normal troponin 2

Management Based on Risk

1. High-risk patients:

   • Activate appropriate emergency protocols (STEMI, aortic dissection)
   • Administer aspirin 162-325 mg (chewed)
   • Consider nitroglycerin for pain relief
   • Establish IV access
   • Prepare for definitive treatment (PCI, surgery) 2

2. Intermediate-risk patients:

   • Admit to observation unit
   • Complete serial troponin testing
   • Consider additional testing (stress test, CT coronary angiography) 1, 2

3. Low-risk patients:

   • May not need urgent diagnostic testing if determined to be truly low risk 1
   • Consider outpatient follow-up 2

Common Pitfalls to Avoid

1. Relying solely on ECG - Approximately 5-10% of MIs present with normal ECGs 2

2. Using nitroglycerin response as a diagnostic test - Other conditions may also respond to nitroglycerin 2

3. Discharging patients with ongoing symptoms - Even if initial tests are negative 2

4. Delaying transfer to ED - For patients initially evaluated in office settings 1

5. Focusing only on cardiac causes - Don't forget about life-threatening non-cardiac causes like pulmonary embolism, aortic dissection, and pneumothorax 1, 2

By following this systematic approach to chest pain evaluation, clinicians can efficiently identify patients with life-threatening conditions while avoiding unnecessary testing and hospitalization for low-risk patients.