What labs should be obtained for a patient with chest pain radiating to the back and increased belching, with a normal heart rate and no murmurs or arrhythmias?

Laboratory Evaluation for Chest Pain Radiating to the Back with Increased Belching

For a patient with chest pain radiating to the back and increased belching, with normal heart rate and no murmurs or arrhythmias, cardiac biomarkers (particularly high-sensitivity troponin) should be obtained urgently along with an ECG, complete blood count, comprehensive metabolic panel, and lipase to evaluate for both cardiac and non-cardiac causes. 1

Initial Laboratory Assessment

Cardiac Evaluation

• High-sensitivity cardiac troponin (preferred) - Most sensitive marker for myocardial injury with rising/falling pattern indicative of acute injury 1
• Serial troponin measurements - Initial and at 3-6 hours to detect a rise or fall pattern
• Complete blood count (CBC) - To assess for anemia or infection
• Basic metabolic panel (BMP) - To evaluate electrolyte abnormalities that could affect cardiac function
• Lipid profile - To assess cardiovascular risk factors

Gastrointestinal Evaluation

• Lipase - To rule out pancreatitis (can present with back pain and belching)
• Liver function tests - To evaluate for hepatobiliary causes

Additional Testing Based on Clinical Suspicion

For Suspected Aortic Pathology

• D-dimer - May be elevated in aortic dissection, though imaging is more definitive

For Suspected Pulmonary Embolism

• D-dimer - High negative predictive value when clinical suspicion is low to intermediate 1
• Arterial blood gas - May show hypoxemia or respiratory alkalosis

Diagnostic Algorithm

1. Immediate ECG - Should be obtained within 10 minutes of presentation 1

   • If ST-elevation: Follow STEMI protocol
   • If ST-depression or T-wave changes: Follow NSTE-ACS protocol
   • If normal or non-diagnostic: Proceed with serial ECGs and biomarkers

2. Cardiac biomarkers

   • High-sensitivity troponin (preferred) 1
   • Serial measurements (0,3-6 hours)
   • Rising/falling pattern indicates acute myocardial injury

3. Additional laboratory tests based on clinical presentation

   • If increased belching and epigastric tenderness: Add lipase, liver function tests
   • If sharp, ripping pain radiating to back: Consider D-dimer (though imaging is more definitive for aortic dissection)

Important Clinical Considerations

• The combination of chest pain radiating to the back with increased belching could represent either:

  • Cardiac ischemia with referred pain and associated GI symptoms
  • Primary gastrointestinal disorder (e.g., GERD with supragastric belching) 2, 3
  • Aortic pathology (dissection, aneurysm)

• Belching can be associated with GERD and may cause chest pain that mimics cardiac symptoms 2

• Radiation of pain to the back raises concern for aortic pathology, which requires prompt evaluation

Common Pitfalls to Avoid

1. Relying solely on a normal ECG - Up to 6% of patients with evolving ACS are discharged with a normal ECG 1

2. Single troponin measurement - Serial measurements are essential to detect a rising or falling pattern 1

3. Attributing symptoms to GERD without excluding cardiac causes - Cardiac causes must be ruled out first due to mortality risk

4. Overlooking aortic pathology - Chest pain radiating to the back is a classic symptom of aortic dissection, which requires urgent evaluation

5. Delaying transfer to ED - If these labs cannot be obtained promptly in an office setting, immediate transfer to ED is recommended rather than delayed evaluation 1

Remember that the clinical presentation of chest pain radiating to the back with increased belching requires thorough evaluation for potentially life-threatening conditions before attributing symptoms to benign causes.