What is the best course of action for a patient with chest pain that worsens when laying supine (on their back), considering potential causes such as acute coronary syndrome, pulmonary embolism, or gastroesophageal reflux disease (GERD)?

Chest Pain Worsening When Lying Supine: Pericarditis Until Proven Otherwise

Chest pain that worsens when lying supine most strongly suggests acute pericarditis, but you must immediately rule out life-threatening causes—particularly acute coronary syndrome, pulmonary embolism, and aortic dissection—before settling on this diagnosis. 1, 2

Immediate Life-Threatening Exclusions Required

Obtain ECG Within 10 Minutes

• An ECG must be acquired and interpreted within 10 minutes of patient arrival regardless of setting 1
• If ST-elevation or new ischemic changes are present, treat as STEMI immediately and transport by EMS 1
• If the initial ECG is nondiagnostic but clinical suspicion remains high, perform serial ECGs 1

Measure Cardiac Troponin Immediately

• Cardiac troponin should be measured as soon as possible in all patients with acute chest pain and any suspicion of ACS 1
• Do not delay transfer to the emergency department for troponin testing if evaluated in an office setting 1

Perform Focused Cardiovascular Examination

The physical examination must specifically assess for: 1

For ACS: Diaphoresis, tachypnea, tachycardia, hypotension, crackles, S3 gallop, or mitral regurgitation murmur (though examination may be completely normal in uncomplicated cases) 1

For Pulmonary Embolism: Tachycardia and dyspnea (present in >90% of patients), pain with inspiration 1

For Aortic Dissection: Pulse differential between extremities (present in 30% of patients), blood pressure differential >20 mmHg between arms, new aortic regurgitation murmur 1, 3

For Pericarditis: Fever, friction rub on auscultation, pleuritic quality to pain 1

Clinical Features Distinguishing Pericarditis

Characteristic Pain Pattern

• Sharp, pleuritic chest pain that increases in the supine position and improves when leaning forward is the hallmark of pericarditis 1, 2
• The pain typically worsens with inspiration and coughing 2
• Pain may be positional and worsen with burping, suggesting pericardial involvement 2

Key Differentiating Features from ACS

Sharp chest pain that increases with inspiration and lying supine is unlikely related to ischemic heart disease 1

• Anginal symptoms are typically described as retrosternal pressure, heaviness, tightness, or squeezing—not sharp pain 1
• Ischemic pain gradually builds over minutes, whereas pericarditic pain can be more sudden 1
• Positional chest pain is usually nonischemic (e.g., musculoskeletal or pericardial) 1

Algorithmic Approach to This Patient

Step 1: Immediate Triage Decision

• If the patient has clinical evidence of ACS or other life-threatening causes, transport urgently to the ED by EMS 1
• High-risk features requiring immediate transfer include: hemodynamic instability, associated diaphoresis, dyspnea, nausea, syncope, age >75 years with accompanying symptoms, or ECG abnormalities 1, 4

Step 2: If Stable, Proceed with Systematic Evaluation

• Obtain ECG within 10 minutes 1
• Measure cardiac troponin 1
• Perform focused cardiovascular examination looking specifically for friction rub, fever, and positional pain characteristics 1
• Check vital signs including oxygen saturation and blood pressure in both arms 2

Step 3: Risk Stratification Based on Findings

If ECG shows diffuse ST elevation with PR depression: This strongly suggests acute pericarditis 1

If troponin is elevated: Consider myopericarditis rather than isolated pericarditis 2

If examination reveals friction rub with fever and positional pain: Pericarditis is highly likely 1

Critical Pitfalls to Avoid

Do Not Rely on Nitroglycerin Response

Relief with nitroglycerin is not diagnostic of myocardial ischemia and should not be used as a diagnostic criterion, as esophageal spasm and other noncardiac conditions also respond to nitroglycerin 1, 2

Do Not Dismiss Atypical Presentations

• Women, elderly patients, and those with diabetes may present with atypical symptoms including sharp or stabbing pain 1, 4
• In patients ≥75 years, ACS should be considered when accompanying symptoms such as shortness of breath, syncope, or acute delirium are present 1, 4

Do Not Delay Transfer for Office-Based Testing

For patients with acute chest pain and suspected ACS initially evaluated in the office setting, delayed transfer to the ED for troponin or other diagnostic testing should be avoided 1

Additional Diagnostic Considerations

While pericarditis is most likely given the positional nature of the pain, also consider: 1, 2

• Gastroesophageal reflux disease/esophagitis: Burning retrosternal pain that may worsen when supine, but typically related to meals and relieved by antacids 2
• Myocarditis: Presents similarly to pericarditis but with more prominent heart failure signs (S3 gallop) 1, 2
• Esophageal rupture: Life-threatening condition with emesis, subcutaneous emphysema, and possible pneumothorax 1