What is the next step in evaluating a patient with chest pain and a normal electrocardiogram (ECG) and negative troponin?

Management of Chest Pain with Normal ECG and Negative Troponin

A single normal ECG and negative troponin are insufficient to exclude acute coronary syndrome (ACS)—perform serial ECGs and repeat troponin measurements, especially if symptoms persist or clinical suspicion remains intermediate-to-high. 1, 2

Critical First Principle: Never Rely on Single Testing

• Up to 6% of patients with evolving ACS are discharged from the emergency department with a normal initial ECG, making serial testing mandatory rather than optional. 1, 2

• A normal or nondiagnostic ECG is reasonably useful but never sufficient to rule out ACS when used alone—decision-making must incorporate serial testing and clinical context. 1

• Left ventricular hypertrophy, bundle branch blocks, and ventricular pacing can mask ischemic changes, further limiting the reliability of a single ECG. 1

Immediate Next Steps

Serial ECG Monitoring (Class I Recommendation)

• Perform repeat ECGs immediately if chest pain recurs, persists, or if the patient's clinical condition deteriorates (including new dyspnea, diaphoresis, hemodynamic instability, or arrhythmias). 1, 2, 3

• Continue serial ECGs until other diagnostic testing definitively rules out ACS—timing should be symptom-driven rather than scheduled at fixed intervals. 1, 2

• When clinical suspicion for ACS remains intermediate-to-high, perform serial ECGs even if symptoms have temporarily resolved. 2

Serial Troponin Measurements

• Measure high-sensitivity cardiac troponin (cTn) as soon as possible if not already obtained, as troponin is the most sensitive test for diagnosing acute myocardial injury. 1, 2, 3

• Repeat troponin measurement at 6-12 hours from symptom onset to detect rising or falling patterns that indicate myocardial injury. 2, 3

• Serial troponin measurements are necessary to identify abnormal values and dynamic patterns that may not be evident on initial testing. 2

Supplemental ECG Leads

• Consider posterior leads (V7-V9) in patients with intermediate-to-high ACS suspicion and nondiagnostic standard ECG (Class IIa recommendation), as left circumflex or right coronary artery occlusions causing posterior wall ischemia are often "electrically silent" on standard 12-lead ECG. 1, 2

• Always compare the current ECG with previous ECGs if available, as subtle new changes may reveal evolving ischemia. 1, 2

Additional Diagnostic Testing

Chest Radiography

• Obtain a chest radiograph to evaluate for alternative cardiac, pulmonary, and thoracic causes of symptoms (pneumonia, pneumothorax, aortic dissection with widened mediastinum, pleural effusion suggesting pulmonary embolism). 1, 2

• This should not delay urgent revascularization if indicated but helps identify non-ACS life-threatening conditions. 1

Advanced Cardiac Testing (After Serial Negative Testing)

• For patients with negative serial ECGs and troponins but intermediate-to-high clinical suspicion, coronary CT angiography (CCTA) demonstrates superior diagnostic performance compared to stress testing, with sensitivity of 96.9% versus 51.6% for dobutamine stress echocardiography. 4

• CCTA showing <50% stenosis, negative ECG stress test, stress echocardiography, or myocardial perfusion scan within the past 12 months allows discharge without further risk stratification if ECG and troponin remain reassuring, given MACE rates of 0.09-0.16% at 1-12 months. 5

• Stress testing and CCTA may allow prognostication but do not predict ACS risk beyond what ECG and troponin already provide in truly low-risk patients. 6

Risk Stratification and Disposition

High-Risk Features Requiring Admission

• Recurrent or persistent ischemic chest pain despite medical therapy 2, 3
• Dynamic ECG changes on serial tracings 2, 3
• Positive second troponin measurement or rising pattern 2, 3
• Hemodynamic instability or life-threatening arrhythmias 2, 3
• New or worsening heart failure 2, 3

Admit these patients with continuous cardiac monitoring and consider urgent coronary angiography. 2, 3

Intermediate-Risk Patients

• Continue observation in chest pain unit or ED with serial ECGs and troponins until the 6-12 hour mark from symptom onset. 2, 3
• Consider anatomic (CCTA) or functional testing (stress test) before discharge. 2, 3

Low-Risk Criteria Allowing Potential Discharge

• No recurrent chest pain after 6-12 hours of observation 2, 3
• Normal or unchanged ECG on serial testing 2, 3
• Two negative troponin measurements 2, 3
• No high-risk features present 2, 3

Consider early stress test or CCTA before discharge with outpatient follow-up within 72 hours. 2, 6

Critical Pitfalls to Avoid

• Never discharge a patient with ongoing chest pain or high clinical suspicion for ACS based solely on a single normal ECG—this is the most dangerous error in chest pain evaluation. 2

• Do not delay repeat ECGs waiting for scheduled intervals if symptoms change—symptom-driven timing takes priority over fixed protocols. 2

• Avoid delayed transfer to the ED for troponin testing from office settings, as this worsens outcomes. 1, 2

• Do not use creatine kinase MB isoenzyme or myoglobin when troponin is available, as these are inferior markers. 2