What is the appropriate initial evaluation and treatment for a patient presenting with chest pain?

Initial Evaluation and Management of Chest Pain

Immediately obtain a 12-lead ECG within 10 minutes of patient presentation and measure cardiac troponin as soon as possible to rapidly identify or exclude acute coronary syndrome and other life-threatening causes. 1, 2

Immediate Actions and Triage

Transport and Initial Assessment

• Activate 9-1-1 for emergency transport if acute coronary syndrome (ACS) or other life-threatening causes are suspected—do not delay transfer for office-based testing 1, 2
• Perform a focused cardiovascular examination immediately to identify ACS, aortic dissection, pulmonary embolism (PE), or esophageal rupture 1
• The examination may be completely normal in uncomplicated acute myocardial infarction, so do not be falsely reassured by negative findings 1

Critical Diagnostic Testing Timeline

• ECG acquisition and interpretation: within 10 minutes of arrival by a trained clinician 1, 2
• Cardiac troponin measurement: as soon as possible, preferably using high-sensitivity troponin (hs-cTn) assays 1, 2, 3
• For repeat troponin testing: 1-2 hours after initial sample for hs-cTn, or 3-6 hours for conventional troponin if initial values are nondiagnostic 1

Focused History Taking

Essential Pain Characteristics to Document

• Nature, onset, duration: sudden severe pain suggests dissection; gradual onset may indicate ACS 2, 3
• Location and radiation: pain in chest, shoulders, arms, neck, back, upper abdomen, or jaw all qualify as anginal equivalents 3
• Associated symptoms: diaphoresis, nausea, shortness of breath, syncope 1
• Precipitating and relieving factors: exertional vs. rest pain, positional changes 1, 2

Special Population Considerations

• Women: specifically ask about accompanying symptoms (nausea, shortness of breath, fatigue) which are more common than in men with ACS 1, 3
• Elderly patients (≥75 years): consider ACS when shortness of breath, syncope, acute delirium, or unexplained falls are present, even without classic chest pain 1, 3
• Patients with diabetes: may present with atypical symptoms including throat or abdominal discomfort 1

Physical Examination Findings by Diagnosis

Life-Threatening Causes (Prioritize These)

• ACS: diaphoresis, tachypnea, tachycardia, hypotension, crackles, S3 gallop, new mitral regurgitation murmur; examination may be normal 1
• Aortic dissection: pulse differential between extremities (present in only 30% of cases), severe abrupt-onset pain, connective tissue disorder features 1
• Pulmonary embolism: tachycardia and dyspnea present in >90% of patients, pain with inspiration, accentuated P2 1
• Esophageal rupture: painful tympanic abdomen, subcutaneous emphysema, pneumothorax in 20% 1

Other Cardiac Causes

• Pericarditis: fever, friction rub, pain worsens when supine and improves sitting forward 1, 3
• Aortic stenosis: systolic murmur, delayed/diminished carotid pulse 1
• Aortic regurgitation: diastolic murmur at right sternal border, rapid carotid upstroke 1

Noncardiac Causes That Reduce ACS Probability

• Costochondritis: tenderness to palpation of costochondral joints—markedly reduces probability of ACS 1
• Pleuritic pain: pain with inspiration—markedly reduces probability of ACS 1
• Pneumothorax: unilateral absence of breath sounds, dyspnea 1
• Pneumonia: fever, localized pain, dullness to percussion, egophony 1

ECG Interpretation and Action

STEMI Criteria

• ST-segment elevation or new left bundle branch block: immediate activation of STEMI protocol, do not delay for further testing 1, 2
• ST-depression in leads V1-V3: obtain posterior leads to evaluate for posterior STEMI 1

NSTE-ACS Findings

• ST-segment depression, T-wave inversions, or transient ST-elevation (high-risk finding): manage according to NSTE-ACS guidelines 1, 2
• Normal ECG does not exclude ACS—integrate with troponin results and clinical picture 1

Risk Stratification and Disposition

Office Setting Protocol

• If ECG is unavailable in the office and noncardiac cause is not evident, refer patient to emergency department 1
• Do not perform office-based troponin testing if it will delay transfer to the ED in suspected ACS 2

Emergency Department Protocol

• Use clinical decision pathways incorporating hs-cTn at 0 and 1-2 hours to identify very low-risk patients (negative predictive value >99.5%) 1, 3
• Low-risk patients with negative serial troponins and ECGs can undergo outpatient stress testing or coronary CT angiography 3, 4
• Intermediate-risk patients benefit most from cardiac imaging and testing 3

Critical Pitfalls to Avoid

• Do not rely on nitroglycerin response as diagnostic of myocardial ischemia—this is not a reliable test 2
• Do not use the term "atypical chest pain"—it is misleading and can be misinterpreted as benign; use "cardiac," "possibly cardiac," or "noncardiac" instead 3
• Do not be falsely reassured by a normal examination—uncomplicated AMI frequently has no abnormal physical findings 1
• Do not delay ECG interpretation—this directly delays critical interventions 2
• Address language barriers with formal translation services in non-English speaking patients to obtain accurate history 1