What is the next step for a patient presenting with shortness of breath and chest pain with a normal Electrocardiogram (EKG)?

Next Steps for Chest Pain and Shortness of Breath with Normal EKG

Immediately measure cardiac troponin as soon as possible and perform serial ECGs at 15-30 minute intervals during the first hour, as a normal initial ECG does not exclude acute coronary syndrome. 1

Critical Initial Actions

Serial ECG monitoring is mandatory because up to 6% of patients with evolving ACS are discharged from the ED with a normal ECG, and a normal ECG may be associated with left circumflex or right coronary artery occlusions that are "electrically silent." 1

• Repeat ECG every 15-30 minutes during the first hour if symptoms persist or recur, especially if clinical suspicion for ACS remains intermediate-to-high 1
• Consider supplemental leads V7-V9 to rule out posterior MI in patients with intermediate-to-high clinical suspicion 1
• Compare with previous ECGs if available to detect subtle new changes 1

Cardiac Biomarker Strategy

Measure cardiac troponin immediately upon presentation, then obtain serial measurements at 3-6 hours after symptom onset using contemporary or high-sensitivity assays. 1

• If initial troponin is normal but ECG changes develop or clinical presentation suggests intermediate/high suspicion for ACS, obtain additional troponin levels beyond 6 hours 1
• High-sensitivity cardiac troponin has >95% negative predictive value for MI when negative on admission, approaching 99% with high-sensitivity assays 1
• A rising and/or falling pattern of troponin values is diagnostic for acute myocardial injury 1

Risk Stratification

Apply validated risk scores (TIMI or GRACE) to guide management intensity and disposition decisions. 1, 2

• High-risk features requiring aggressive management include: recurrent ischemia during observation, elevated troponin, hemodynamic instability, new ST-segment changes, or clinical deterioration 1, 2
• Intermediate-risk patients benefit most from cardiac imaging and further testing 2
• Low-risk patients by structured assessment with normal ECG and troponin do not require urgent diagnostic testing for suspected CAD 2

Evaluate for Alternative Life-Threatening Diagnoses

A normal ECG does not exclude other emergencies that present with chest pain and dyspnea. 1, 2

• Pulmonary embolism: Look for tachycardia (present in >90%), tachypnea, pleuritic pain, risk factors (immobility, recent surgery, malignancy), and consider ECG findings like S1Q3T3 pattern or right bundle branch block 2, 3
• Aortic dissection: Assess for sudden-onset "ripping/tearing" pain radiating to back, pulse differentials between extremities, blood pressure differential >20 mmHg, or new aortic regurgitation murmur 1, 2
• Tension pneumothorax: Examine for severe dyspnea, unilateral absent breath sounds, tracheal deviation, jugular venous distension, and hypotension 2
• Pericardial tamponade: Look for dyspnea, chest discomfort, hypotension, and consider urgent transthoracic echocardiography 2

Obtain Chest Radiography

Perform chest radiography to evaluate for cardiac, pulmonary, and thoracic causes, but do not delay urgent interventions if indicated. 1, 4

• Chest x-ray can identify pneumonia, pneumothorax, rib fractures, pleural effusions, pulmonary artery enlargement, widened mediastinum (aortic dissection), or heart size/pulmonary congestion 1
• Normal chest x-ray does not exclude PE or ACS 1

Physical Examination Priorities

Perform focused cardiovascular examination looking for specific findings that suggest serious pathology: 1, 4

• Diaphoresis, tachypnea, tachycardia, hypotension suggesting ACS 4
• Crackles, S3 gallop, new mitral regurgitation murmur indicating heart failure or ischemic complications 4
• Pulse/blood pressure differentials suggesting aortic dissection 2
• Unilateral absent breath sounds suggesting pneumothorax 2

Disposition Algorithm

Immediate transfer to ED by EMS if clinical evidence of ACS or life-threatening cause, hemodynamic instability, or high-risk features present. 1, 2, 4

Observation unit or admission if intermediate risk with abnormal initial workup, recurrent symptoms during observation, or elevated troponin. 2

Outpatient management acceptable only if low risk by structured assessment, normal ECG and troponin, and no high-risk features. 2

Critical Pitfalls to Avoid

• Do not rely on nitroglycerin response as diagnostic for myocardial ischemia—esophageal spasm and other conditions respond similarly 1, 5, 4
• Do not delay transfer for office-based troponin testing when ACS is suspected—delayed transfer is harmful 1, 5, 4
• Do not assume young age excludes ACS—it can occur even in adolescents without traditional risk factors 5
• Do not base decisions solely on a single normal ECG—left ventricular hypertrophy, bundle branch blocks, and ventricular pacing may mask ischemia 1
• Sharp, pleuritic pain does not exclude ACS—pericarditis and atypical presentations occur 5

Special Population Considerations

Women are at risk for underdiagnosis and should be asked specifically about accompanying symptoms more common in women with ACS: nausea, fatigue, dyspnea, jaw pain, and epigastric discomfort. 1, 5

Older adults ≥75 years may present with atypical symptoms like isolated dyspnea, syncope, acute delirium, or unexplained falls without classic chest pain—maintain high suspicion for ACS. 1, 5