What are the appropriate diagnostic steps and treatment options for pain radiating to the left sternum?

Pain Radiating to Left Sternum: Diagnostic and Treatment Approach

Pain radiating to the left sternum requires immediate evaluation to exclude life-threatening cardiac causes, particularly acute coronary syndrome, which characteristically presents as retrosternal discomfort with left-sided radiation. 1

Immediate Assessment (Within 10 Minutes)

Obtain a 12-lead ECG within 10 minutes of presentation to identify ST-elevation myocardial infarction (STEMI), which is the highest priority diagnosis to exclude. 1, 2

Critical Red Flags Requiring Emergency Evaluation

• Sudden onset "ripping" or "tearing" pain radiating to the back suggests acute aortic dissection and mandates immediate CT angiography of chest, abdomen, and pelvis. 1, 2
• Pain described as "worst chest pain of my life" in a hypertensive patient or those with bicuspid aortic valve/aortic dilation is highly suspicious for aortic dissection. 1, 2
• Pulse differential between extremities (present in 30% of dissections) significantly increases probability of aortic dissection. 2
• Dyspnea with pleuritic chest pain and tachycardia suggests pulmonary embolism requiring CTA with PE protocol. 2

Characterizing the Pain Pattern

Features Suggesting Acute Coronary Syndrome

• Retrosternal pressure, tightness, heaviness, or squeezing that builds gradually over several minutes (not sudden or fleeting). 1
• Radiation to the left arm makes right coronary artery disease less than 10% likely. 3
• Triggered by physical exertion or emotional stress, or occurring at rest with minimal exertion. 1
• Associated symptoms: dyspnea, diaphoresis, nausea, vomiting, lightheadedness, or upper abdominal discomfort. 1

Features Suggesting Non-Cardiac Causes

• Sharp, stabbing pain that worsens with inspiration and lying supine indicates pericarditis, not ischemia. 1
• Fleeting pain lasting only seconds is unlikely related to ischemic heart disease. 1
• Positional chest pain is usually musculoskeletal. 1
• Pain localized to a very limited area is unlikely myocardial ischemia. 1

Diagnostic Algorithm

Step 1: ECG Interpretation (Within 10 Minutes)

• ST-segment elevation or Q waves indicating acute MI (specificity 95%, LR 5.3). 1, 4
• Any ST-segment depression or ischemic changes (specificity 91%, LR 3.6). 4

Step 2: Risk Stratification Using HEART or TIMI Score

The HEART score (0-10) or TIMI score (0-7) incorporating the first cardiac troponin provides the most diagnostic information. 4

• HEART score 7-10 (high risk): LR 13 for ACS—requires admission and cardiology consultation. 4
• HEART score 0-3 (low risk): LR 0.20 for ACS—safe for discharge with outpatient follow-up. 4
• TIMI score 5-7 (high risk): LR 6.8 for ACS—requires intensive monitoring. 4
• TIMI score 0-1 (low risk): LR 0.31 for ACS—appropriate for observation unit or discharge. 4

Step 3: Cardiac Biomarkers

Measure high-sensitivity troponin as soon as possible after presentation to confirm or exclude NSTEMI. 2, 5

Step 4: Additional Testing Based on Clinical Suspicion

If aortic dissection suspected (ripping pain, back radiation, pulse differential):

• CT angiography of chest, abdomen, and pelvis is first-line. 2
• If CT contraindicated, perform transesophageal echocardiography or cardiac MRI. 2

If pulmonary embolism suspected (dyspnea, pleuritic pain, tachycardia):

• CTA chest with PE protocol for stable patients. 2

If chest wall pain without cardiac features:

• Chest radiography is the initial imaging study. 1
• CT chest with or without IV contrast if radiography is normal but symptoms persist. 1

Treatment Approach

For Confirmed ACS

• Dual antiplatelet therapy (aspirin plus P2Y12 inhibitor). 5
• Anticoagulation with heparin or low-molecular-weight heparin. 5
• STEMI: Primary PCI within 60-120 minutes if available; fibrinolysis if PCI unavailable. 5
• NSTEMI/Unstable angina: Risk stratification and early invasive strategy for high-risk patients. 5

For Non-Cardiac Chest Pain

If gastroesophageal reflux disease suspected (approximately 50% of non-cardiac chest pain):

• Therapeutic trial of high-dose proton pump inhibitor for 1-2 weeks. 6, 7

Critical Pitfalls to Avoid

• Do not use nitroglycerin response as a diagnostic criterion—esophageal spasm also responds to nitroglycerin. 1, 2
• Do not assume absence of typical anginal features excludes ACS—women, elderly, and diabetic patients may present with atypical symptoms including throat or abdominal discomfort. 1
• Do not rely solely on chest X-ray for aortic dissection—absence of widened mediastinum does not exclude dissection. 2
• Do not delay transfer to emergency department for patients with suspected life-threatening causes. 2
• Do not fail to check pulse differentials in all four extremities—this critical finding increases probability of dissection when present. 2