What is the next step in managing an adult patient with squeezing chest pain, normal electrocardiogram (EKG), and normal laboratory results, possibly with a history of cardiovascular risk factors such as hypertension, diabetes, or hyperlipidemia?

Management of Squeezing Chest Pain with Normal EKG and Labs

Proceed immediately with serial cardiac troponin measurements at 10-12 hours from symptom onset and perform serial ECGs, as a single normal troponin and ECG do not exclude acute coronary syndrome (ACS), particularly in patients with cardiovascular risk factors. 1, 2

Immediate Next Steps

Serial Cardiac Biomarker Testing

• Obtain repeat high-sensitivity troponin at 10-12 hours after the onset of chest pain symptoms, as initial normal troponin does not rule out myocardial infarction 1
• A single normal troponin measurement is insufficient—up to 6% of patients with evolving ACS are discharged from the ED with a normal initial ECG 1
• Blood samples for CK-MB mass and troponin should be drawn on admission and again at 10-12 hours after symptom onset for both diagnosis and risk assessment 1

Serial Electrocardiographic Monitoring

• Perform repeat ECGs every 15-30 minutes if symptoms persist or recur, as ischemic changes may evolve over time 1
• Compare new ECGs with previous tracings if available, as a normal or unchanged ECG is useful but not sufficient to rule out ACS 1
• Consider supplemental leads V7-V9 to evaluate for posterior myocardial infarction, which may not be evident on standard 12-lead ECG 1

Risk Stratification During Observation Period

Chest Pain Unit Observation

• Observe patients for 10-12 hours in a chest pain unit or emergency department rather than immediate discharge, as the risk of missed ACS is unacceptably high without proper observation 1
• This observation period allows time for serial troponin measurements and detection of evolving ECG changes 1, 3
• In the pre-aspirin and pre-heparin era, 20-30% of patients with missed ACS either died or had complications—proper observation mitigates this risk 1

High-Risk Features to Monitor

• Recurrent chest pain during observation warrants immediate repeat ECG and consideration for urgent cardiology consultation 1, 2
• Development of hemodynamic instability, new arrhythmias, or signs of heart failure indicate high-risk features requiring immediate invasive evaluation 1
• Elevated troponin on repeat testing (>0.1 μg/L) significantly changes management and indicates need for antiplatelet therapy and heparin 1

Disposition Algorithm Based on Serial Testing Results

If Serial Troponins Remain Normal and No ECG Changes

• Proceed with stress testing before discharge or as outpatient to evaluate for inducible ischemia 1, 3
• Exercise stress testing is appropriate for patients who can exercise and have interpretable baseline ECG 1, 3
• Stress imaging (nuclear or echocardiographic) should be used for patients with baseline ECG abnormalities that preclude interpretation, such as left bundle branch block or left ventricular hypertrophy 1
• An exercise test before discharge can reveal severe myocardial ischemia at low workload 1

If Troponin Becomes Positive or ECG Changes Develop

• Admit to hospital for invasive strategy within 24-48 hours for patients with positive troponin without ongoing high-risk features 2, 3
• Immediate cardiac catheterization is indicated for ongoing chest pain with ischemic ECG changes, elevated troponin with recurrent ischemia, hemodynamic instability, or major arrhythmias 2, 3
• Initiate aspirin (250-500 mg chewable), clopidogrel, and low-molecular-weight heparin if ACS is confirmed 1, 2

Critical Caveats and Common Pitfalls

Do Not Rely on Single Normal Results

• A normal ECG occurs in more than 50% of patients with chronic stable angina and does not exclude significant coronary artery disease 1
• Left ventricular hypertrophy, bundle branch blocks, and ventricular pacing may mask signs of ischemia or injury on ECG 1
• The combination of normal initial troponin and normal ECG still requires serial testing over 10-12 hours 1

Consider Alternative Life-Threatening Diagnoses

• Aortic dissection must be considered in hypertensive patients, particularly if pain is sudden, severe, ripping, or radiating to the back 1, 2
• Pulmonary embolism should be evaluated if clinical suspicion exists, even with normal cardiac workup 1
• Obtain chest X-ray to evaluate for pneumothorax, pneumonia, or intrathoracic tumors if cardiac causes are excluded 1

Special Populations Requiring Heightened Vigilance

• Patients with diabetes mellitus may present with atypical symptoms including isolated dyspnea without chest pain and require lower threshold for testing 1, 3
• Women are at higher risk for underdiagnosis and commonly present with accompanying symptoms such as nausea, fatigue, jaw/neck/back pain, and palpitations in addition to chest pain 1, 4
• Traditional risk assessment tools often underestimate risk in women and may misclassify them as having nonischemic chest pain 1

Avoid Premature Discharge

• The risk of discharging patients without correctly diagnosing ACS is unacceptably high without proper 10-12 hour observation and serial testing 1
• Patients admitted to coronary care units had 30-day mortality of 6.8% compared to 10.9% for those treated in general internal medicine wards, highlighting the importance of appropriate triage 1