What are the initial diagnostic steps for a patient presenting with sudden onset severe chest pain?

Initial Diagnostic Steps for Sudden Onset Severe Chest Pain

For patients presenting with sudden onset severe chest pain, an ECG should be acquired and reviewed for ST-segment elevation myocardial infarction (STEMI) within 10 minutes of arrival, and cardiac troponin should be measured as soon as possible when ACS is suspected. 1, 2

Immediate Assessment

• Unless a noncardiac cause is evident, an ECG should be performed for all patients with chest pain; if an ECG is unavailable in the office setting, the patient should be referred to the ED 1
• Patients with clinical evidence of ACS or other life-threatening causes of chest pain seen in an office setting should be transported urgently to the ED, ideally by EMS 1, 3
• Cardiac troponin should be measured as soon as possible after presentation in the ED setting for patients with suspected ACS 1, 2
• For suspected heart attack, administer fast-acting aspirin (250-500 mg, chewable or water-soluble) as soon as possible 1, 3

Focused History and Physical Examination

• Evaluate chest pain characteristics, including nature, onset and duration, location and radiation, severity, precipitating factors, relieving factors, and associated symptoms 2, 3
• Indicators of potentially serious conditions include interruption of normal activity and accompanying cold sweat, nausea, vomiting, fainting, or anxiety/fear 1, 3
• Look for specific physical examination findings based on suspected etiology 1, 2:
  • ACS: diaphoresis, tachypnea, tachycardia, hypotension, crackles, S3, mitral regurgitation murmur
  • Aortic dissection: pulse differential (30% of patients), severe pain with abrupt onset
  • Pulmonary embolism: tachypnea, tachycardia, hypoxemia, signs of DVT
  • Pneumothorax: unilateral absence of breath sounds, dyspnea and pain on inspiration

ECG-Directed Management

• If the initial ECG shows STEMI, treat according to STEMI guidelines 1, 2
• If the ECG shows ST depression or new T-wave inversions, treat according to non-ST-segment elevation ACS guidelines 1
• If the initial ECG is nondiagnostic but clinical suspicion for ACS remains high, perform serial ECGs to detect potential ischemic changes 1
• In patients with intermediate-to-high clinical suspicion for ACS and nondiagnostic initial ECG, supplemental electrocardiographic leads V7 to V9 are reasonable to rule out posterior myocardial infarction 1

Additional Diagnostic Testing

• Chest radiography is useful to evaluate for other potential cardiac, pulmonary, or thoracic causes of chest pain 2, 4
• Risk stratification tools such as HEART or TIMI scores can help guide management decisions 5
• The HEART score is particularly useful for identifying low-risk patients (score 0-3) who may not require admission (LR 0.20) 5

Common Pitfalls and Caveats

• Relief with nitroglycerin should not be used as a diagnostic criterion for myocardial ischemia, as other conditions may show comparable response 3
• Physical examination contributes minimally to diagnosing heart attack unless there is associated shock 3
• Office-based troponin testing should not delay transfer to the ED in suspected ACS 2
• Women, elderly patients, and those with diabetes may present with atypical symptoms such as shortness of breath, nausea, vomiting, or lightheadedness 3, 6
• Delayed ECG interpretation can delay critical interventions 2
• For patients with chest pain and negative troponin findings, nonconcerning vital signs, and nonischemic ECG findings, short-term clinically relevant adverse cardiac events are rare (0.06%), suggesting that routine inpatient admission may not be beneficial for this low-risk group 7