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

Initial Workup for Intermittent Chest Pain

The initial workup for a patient presenting with intermittent chest pain should include a 12-lead ECG within 10 minutes of arrival, cardiac troponin measurement, focused history, and physical examination to rapidly identify life-threatening causes. 1

Immediate Assessment

• Obtain a 12-lead ECG within 10 minutes of patient presentation to identify ST-segment elevation myocardial infarction (STEMI) or other concerning ECG changes 1
• Measure cardiac troponin (preferably high-sensitivity cardiac troponin) as soon as possible after presentation 1
• Perform a focused history capturing all characteristics of chest pain including nature, onset/duration, location/radiation, precipitating factors, relieving factors, and associated symptoms 1
• Conduct physical examination to identify potential cardiac and non-cardiac causes 1

History and Physical Examination Focus

• Nature of pain: Retrosternal discomfort (pressure, heaviness, tightness) suggests cardiac origin; sharp pain increasing with inspiration suggests non-cardiac causes like pericarditis 1
• Onset and duration: Gradual build over minutes suggests angina; sudden onset of ripping pain with radiation to back suggests aortic syndrome 1
• Associated symptoms: Assess for dyspnea, diaphoresis, nausea, vomiting, syncope 1
• Physical exam: Evaluate vital signs, heart sounds, lung fields, and check for subcutaneous emphysema, unilateral breath sounds (pneumothorax), friction rub (pericarditis) 1

ECG Evaluation

• If initial ECG is nondiagnostic but clinical suspicion for ACS remains high, perform serial ECGs at short intervals 1
• Consider supplemental electrocardiographic leads V7-V9 to rule out posterior myocardial infarction if initial ECG is nondiagnostic 1
• Categorize ECG findings as:
  • STEMI (immediate reperfusion pathway)
  • ST-depression/T-wave inversions (possible NSTE-ACS)
  • Nondiagnostic or normal (requires further evaluation) 1

Laboratory Testing

• Measure high-sensitivity cardiac troponin (hs-cTn) initially and repeat at appropriate intervals 1
  • For hs-cTn assays: repeat in 1-2 hours
  • For conventional troponin assays: repeat in 3-6 hours 1
• Consider hemoglobin measurement to detect anemia as a potential cause 1

Risk Stratification

• Patients can be stratified into high-risk and low-risk categories based on:
  • ECG changes (especially dynamic ST changes)
  • Troponin elevation
  • Clinical features (recurrent pain, hemodynamic instability)
  • Presence of diabetes mellitus 1

Additional Testing Based on Initial Findings

• If initial assessment suggests high-risk features (elevated troponins, dynamic ECG changes, hemodynamic instability), consider:

  • Echocardiography to assess left ventricular function and rule out other cardiovascular causes 1
  • Early coronary angiography for highest-risk patients 1

• For intermediate-risk patients:

  • Observation with serial ECGs and troponins
  • Consider stress testing or cardiac imaging if initial workup is negative 1

Important Considerations

• An undetectable high-sensitivity troponin (<5 ng/L) combined with a non-ischemic ECG has a negative predictive value of 99.8% for MI within 30 days 2
• Initial assessment by cardiology residents based on chest pain characteristics, ECG, and troponin has high sensitivity (100%) but lower specificity (54.2%) 3
• Normal ECGs are associated with extremely low risk of acute myocardial infarction 4

Pitfalls to Avoid

• Delaying ECG acquisition beyond 10 minutes of arrival 1
• Premature discharge without adequate cardiac biomarker testing 1
• Missing posterior MI by not considering supplemental ECG leads when indicated 1
• Failing to repeat troponin measurements at appropriate intervals (1-2 hours for hs-cTn, 3-6 hours for conventional troponin) 1
• Overlooking non-cardiac causes of chest pain such as pulmonary embolism, pneumothorax, or aortic dissection 5, 6