What are the next steps if an electrocardiogram (EKG) is normal and cardiac auscultation is normal?

Next Steps with Normal EKG and Normal Cardiac Auscultation

If the EKG is normal and cardiac auscultation is normal, you must obtain serial cardiac troponins at presentation and 3-6 hours after symptom onset to exclude acute coronary syndrome, as 1-6% of patients with ACS present with a normal EKG. 1

Critical Understanding

• A normal EKG does not exclude acute coronary syndrome—approximately 5-40% of patients with evolving acute myocardial infarction have a normal initial EKG 1
• Among patients with normal EKG and no history of coronary artery disease, 2% will still develop acute myocardial infarction 1
• Normal cardiac auscultation similarly does not rule out life-threatening cardiac conditions 1

Immediate Management Algorithm

Step 1: Serial Cardiac Biomarkers (Mandatory)

• Obtain cardiac troponin I or T at presentation and repeat at 3-6 hours after symptom onset 1
• If symptom onset time is unclear, obtain additional troponin levels beyond 6 hours when clinical suspicion remains intermediate or high 1
• A negative troponin with high-sensitivity assays confers >99% negative predictive value for MI 1

Step 2: Serial EKGs

• Repeat EKG at 15-30 minute intervals during the first hour if the patient remains symptomatic 1
• This detects evolving ischemic changes that may not be present initially 1
• A normal EKG may mask left circumflex or right coronary artery occlusions, which can be electrically silent 1

Step 3: Risk Stratification

• Apply validated risk scores (e.g., TIMI score) to assess prognosis 1
• Consider observation in a chest pain unit for 10-12 hours after symptom onset 1
• The risk of discharging patients without proper observation is equivalent to the pre-aspirin/pre-heparin era: 20-30% mortality or reinfarction 1

Low-Risk Patient Pathway

If after observation the patient has:

• No recurrence of chest pain 1
• Negative serial troponins at 6-12 hours 1
• No new EKG changes 1

Then proceed with:

• Stress testing before discharge to detect severe myocardial ischemia at low workload 1
• If stress test shows significant ischemia at low workload, proceed to coronary angiography 1
• If stress test is inconclusive, consider stress echocardiography or myocardial perfusion scintigraphy 1

Additional Diagnostic Considerations

Chest X-Ray

• Obtain chest X-ray to exclude non-cardiac causes: pleuritis, pneumonia, pneumothorax, intrathoracic tumors 1
• May reveal widened mediastinum suggesting aortic dissection 1

Other Life-Threatening Conditions to Exclude

When EKG and cardiac exam are normal but clinical suspicion remains high, consider:

• Pulmonary embolism 1
• Aortic dissection 1
• Acute pericarditis 1
• Pneumothorax 1

These conditions are rare compared to acute coronary syndromes but are life-threatening 1

Common Pitfalls to Avoid

• Never discharge a patient with chest pain based solely on normal EKG and exam—serial troponins and observation are mandatory 1
• Do not obtain only a single troponin measurement—the rising and/or falling pattern over 3-6 hours is essential for diagnosis 1
• Do not skip stress testing in low-risk patients—it confirms or excludes coronary artery disease and assesses future event risk 1
• Do not assume normal EKG means normal coronary arteries—posterior leads (V7-V9) may be needed for posterior MI 1

Medication Considerations During Observation

For patients under observation with suspected but unconfirmed ACS:

• Aspirin should be given as soon as possible if ACS is suspected 1
• Low-molecular-weight heparin may be started in the emergency department 1
• These can be discontinued if serial troponins remain negative and no EKG changes develop 1