What is the appropriate emergency evaluation and initial management for an adult presenting with acute chest pain?

Emergency Evaluation and Initial Management of Acute Chest Pain

All adults presenting with acute chest pain must have a 12-lead ECG obtained and interpreted within 10 minutes of arrival and cardiac troponin measured immediately to identify life-threatening conditions, particularly acute coronary syndrome, aortic dissection, and pulmonary embolism. 1

Immediate Actions (First 10 Minutes)

Mandatory Diagnostic Tests

• Obtain 12-lead ECG within 10 minutes to detect STEMI (ST-elevation ≥1 mm in contiguous leads), ST-depression, T-wave inversions, or other acute ischemic changes 1, 2
• Draw cardiac troponin immediately upon arrival—this is the most sensitive and specific biomarker for myocardial injury 1, 2
• Assess vital signs including heart rate, blood pressure (all four extremities to detect pulse differentials), respiratory rate, and oxygen saturation 1, 2
• Place on continuous cardiac monitoring with emergency resuscitation equipment and defibrillator at bedside 3

Initial Medical Management

• Administer aspirin 160-325 mg (chewed, not swallowed) immediately unless contraindicated by active bleeding or known allergy 2, 3, 4
• Give sublingual nitroglycerin 0.3 mg every 5 minutes for up to 3 doses if systolic BP >90 mmHg and heart rate 50-100 bpm 2, 3
• Provide IV morphine 4-8 mg with additional 2 mg doses every 5 minutes for pain relief, as pain increases sympathetic activation and myocardial oxygen demand 2, 4
• Administer oxygen 2-4 L/min if patient is dyspneic, has heart failure features, or oxygen saturation is low 4

Critical History Elements to Document

Pain Characteristics That Predict High Likelihood of ACS

• Quality: Pressure, squeezing, gripping, heaviness, tightness, or constriction (patients rarely use the word "pain" itself) 2
• Onset: Gradual build over several minutes, not instantaneous 1, 2
• Location: Retrosternal with radiation to left arm, neck, jaw, or between shoulder blades 1, 2
• Duration: Several minutes of sustained discomfort, not fleeting seconds 1, 2
• Precipitating factors: Physical exertion or emotional stress 2

Associated Symptoms That Increase ACS Probability

• Dyspnea or shortness of breath 1, 2
• Diaphoresis 1, 2
• Nausea or vomiting 1, 2
• Lightheadedness, presyncope, or syncope 1, 2

Cardiovascular Risk Factors to Assess

• Age and sex (women typically present 8-10 years older than men) 2
• Diabetes mellitus, hypertension, hyperlipidemia 1, 2
• Smoking history 1
• Family history of premature coronary artery disease 1, 2

Physical Examination Findings Requiring Immediate Escalation

High-Risk Cardiovascular Signs

• Hemodynamic instability: Systolic BP <100 mmHg, heart rate >100 or <50 bpm 2, 4
• Heart failure signs: Crackles, S3 gallop, elevated jugular venous pressure 1, 2
• New murmurs: Mitral regurgitation (papillary muscle dysfunction) or aortic regurgitation (dissection) 1, 2
• Pulse differential: Asymmetry between all four extremities suggests aortic dissection 2

Signs of Alternative Life-Threatening Diagnoses

• Unilateral absent breath sounds + tracheal deviation + hypotension: Tension pneumothorax 2
• Subcutaneous emphysema: Esophageal rupture or pneumomediastinum 2
• Pericardial friction rub + positional pain: Pericarditis or tamponade 1, 2

Serial Testing Protocol

Troponin Measurement Strategy

• High-sensitivity troponin: Repeat at 1-3 hours after initial sample 2, 4
• Conventional troponin: Repeat at 3-6 hours after initial sample 2, 4
• Single-sample rule-out: If symptom onset ≥3 hours before ED arrival, normal ECG, and high-sensitivity troponin below limit of detection, myocardial injury is excluded 2
• Use sex-specific thresholds (>16 ng/L for women vs >34 ng/L for men) to avoid missing 30% of women with STEMI 2

Serial ECG Monitoring

• Repeat ECG every 15-30 minutes during the first hour if symptoms persist or clinical suspicion remains intermediate-to-high 4
• Obtain supplemental leads V7-V9 to exclude posterior MI if initial ECG is nondiagnostic 3, 4
• Compare with previous ECGs if available to detect subtle changes 4
• A normal initial ECG does not exclude ACS—up to 6% of patients with evolving ACS are discharged with normal ECGs 4

Life-Threatening Differential Diagnoses

Acute Coronary Syndrome

• Retrosternal pressure building over minutes with radiation to left arm/neck/jaw, associated with diaphoresis, dyspnea, nausea 1, 2
• Only 5.1% of ED chest pain patients have ACS, but it remains the leading cause of death 1

Acute Aortic Dissection

• Sudden-onset severe tearing or ripping pain radiating to back 1, 2
• Pulse differential occurs in ~30% (more common in type A) 2
• Combination of severe pain + pulse differential + widened mediastinum on chest X-ray predicts >80% probability 2
• Syncope in >10%; aortic regurgitation in 40-75% of type A dissections 2

Pulmonary Embolism

• Sudden dyspnea with pleuritic chest pain worsening on inspiration 1, 2
• Tachycardia and dyspnea present in >90% of patients 2
• Right ventricular strain pattern may appear on ECG 1

Tension Pneumothorax

• Dyspnea with inspiratory chest pain 2
• Unilateral absent breath sounds, tracheal deviation, hypotension 2

Esophageal Rupture (Boerhaave Syndrome)

• History of forceful vomiting preceding chest pain 2
• Subcutaneous emphysema, pneumothorax in ~20% 2

Pericardial Tamponade

• Pleuritic chest pain worsening when supine 2
• Fever, pericardial friction rub, hemodynamic compromise 2

Special Population Considerations

Women

• Women are at high risk for underdiagnosis and should be assumed to have cardiac etiology until proven otherwise 1, 2
• Emphasize accompanying symptoms: Nausea (32% vs 23% in men), jaw/neck pain (10% vs 4%), fatigue, dyspnea, epigastric discomfort, back pain 1, 2
• Women present ~1 hour later after symptom onset (median 300 vs 238 minutes) 2
• Women undergo coronary angiography less often (73.8% vs 84.3%) and receive less aggressive therapy 2

Older Adults (≥75 Years)

• Consider ACS when accompanying symptoms include: Isolated dyspnea, syncope, acute delirium, or unexplained falls—even without classic chest pain 1, 2, 4
• Patients with diabetes are more likely to present with vague abdominal symptoms, confusion, or isolated dyspnea 2

Risk Stratification and Disposition

High-Risk Features Requiring Immediate CCU Admission

• Prolonged ongoing rest pain with ischemic ECG changes 1, 4
• Positive troponin (>99th percentile) 4
• Hemodynamic instability or left ventricular failure 4
• Age >75 years with accompanying symptoms 1, 2

Intermediate-Risk Features

• Prior MI or coronary artery disease 4
• Diabetes mellitus 4
• Rest angina >20 minutes that has resolved 4

Low-Risk Patients

• For low-risk patients with normal ECG and negative troponin: Urgent diagnostic testing for suspected CAD is not needed 1
• Observation unit management (10-12 hours) with continuous cardiac monitoring, resuscitation equipment, and ST-segment surveillance is preferred over direct discharge 4
• Historical data show 20-30% of unstable angina patients experienced death or MI within four weeks without proper observation 4

Critical Pitfalls to Avoid

Terminology

• Never use "atypical chest pain"—this term is misleading and can cause symptoms to be misinterpreted as benign 1, 2
• Use "cardiac," "possibly cardiac," or "noncardiac" instead for accurate risk stratification 1, 2

Diagnostic Errors

• Do not rely on nitroglycerin response to differentiate cardiac from esophageal pain—esophageal spasm also responds 2
• Do not assume young age excludes ACS—it can occur in adolescents without risk factors 5
• Do not delay transfer from office settings for additional testing when ACS is suspected—transport urgently by EMS 1, 2
• Sharp, pleuritic pain does not exclude ACS—13% of patients with pleuritic features still have acute myocardial ischemia 2

Transport Decisions

• Patients with clinical evidence of ACS or life-threatening causes must be transported by EMS, not personal automobile 1, 2
• EMS allows pre-hospital ECG acquisition (reduces mortality), intervention for complications en route, defibrillation capability, and shorter travel times 2

Additional Laboratory Testing

• CK-MB mass: Obtain on admission and at 10-12 hours after symptom onset (though troponin is preferred) 4
• Low-molecular-weight heparin: Initiate in ED for suspected ACS 4
• Coagulation studies (INR/PTT): Essential given anticoagulation requirements 3
• Chest radiograph: Evaluate for cardiomegaly, pulmonary edema, widened mediastinum, pneumothorax 3, 4
• Basic metabolic panel and electrolytes 3

Clinical Decision Pathways

• Use structured clinical decision pathways routinely in ED and outpatient settings 1
• Apply validated risk scores (TIMI or GRACE) to guide therapy intensity and disposition 4
• Patients at intermediate risk or intermediate-to-high pretest probability of obstructive CAD benefit most from cardiac imaging and testing 1