What is the initial workup for a patient presenting with chest pain in an urgent care setting?

Initial Workup for Chest Pain in Urgent Care

For all patients presenting with chest pain in an urgent care setting, an ECG should be acquired and reviewed for ST-segment elevation myocardial infarction (STEMI) within 10 minutes of arrival, and if unavailable, the patient should be referred to the ED. 1

Step 1: Immediate Assessment (First 10 Minutes)

• Obtain 12-lead ECG immediately (within 10 minutes of arrival) 1
• Focused cardiovascular examination to identify potentially serious causes of chest pain 1
• Vital signs (heart rate, blood pressure, respiratory rate, oxygen saturation)
• Brief targeted history focusing on:
  • Chest pain characteristics (nature, onset, location, radiation, severity, precipitating/relieving factors)
  • Associated symptoms (diaphoresis, nausea, vomiting, shortness of breath)

ECG Interpretation

• ST-segment elevation: Highly specific (80-90%) for acute myocardial infarction 1
• ST-segment depression: Indicates myocardial ischemia (specificity 95%) 1, 2
• T-wave inversions: Lower specificity but still concerning for ischemia 1
• Normal ECG: Does not exclude ACS (5-40% of patients with normal ECG may have evolving AMI) 1

Step 2: Risk Stratification

High-Risk Features (Immediate ED Transfer)

• ST-segment elevation or new LBBB on ECG 1, 3
• Hemodynamic instability or arrhythmias 1
• Severe, ripping chest pain suggestive of aortic dissection 1
• Chest pain with accompanying symptoms in patients ≥75 years (shortness of breath, syncope, delirium, unexplained fall) 1

Chest Pain Characteristics

• Higher probability of ischemia: Central/left-sided, pressure/heaviness/tightness, exertional/stress-related, retrosternal 1
• Lower probability of ischemia: Right-sided, fleeting, sharp, stabbing, pleuritic 1
• Red flags for aortic dissection: Sudden onset of ripping pain ("worst pain of life"), especially with radiation to back 1, 3

Step 3: Management Decision

If ACS is Suspected:

1. Do not delay transfer to ED for cardiac troponin testing 1
2. Transport urgently to ED, ideally by EMS 1
3. Consider aspirin 160-325 mg (chewed) unless contraindicated 3
4. Administer oxygen if saturation <90% 3
5. Establish IV access 3

If Non-Cardiac Cause is Evident:

• Manage appropriately based on suspected diagnosis
• Consider other serious causes:
  • Pulmonary embolism: Tachycardia + dyspnea (>90%), pain with inspiration 3
  • Pneumothorax: Unilateral decreased/absent breath sounds 3
  • Pericarditis: Fever, pleuritic pain worse in supine position, friction rub 3

Important Caveats

• History and physical examination alone cannot rule out ACS - even "atypical" symptoms cannot exclude ACS 4
• Traditional cardiac risk factors have limited diagnostic utility in acute settings 4
• Clinician gestalt has very low predictive ability for ruling out ACS, even with experience 4
• Women and elderly patients often present with atypical symptoms 3
• Normal ECG does not exclude ACS - up to 40% of patients with AMI may have a normal initial ECG 1

Risk Scoring Systems

Consider using validated risk scores such as:

• HEART Score
• TIMI Risk Score
• EDACS (Emergency Department Assessment of Chest Pain Score)

The HEART score (0-3) has shown good ability to identify patients at low risk (LR 0.20) 2

Summary Algorithm

1. Obtain ECG within 10 minutes
2. If ST-elevation or other high-risk features: Immediate ED transfer
3. If intermediate risk: Consider ED transfer for troponin testing
4. If low risk and non-cardiac cause evident: Manage appropriately
5. If ECG unavailable in urgent care: Refer to ED

Remember that chest pain workup in urgent care is primarily focused on identifying patients who need emergency department evaluation rather than making definitive diagnoses.