Patients presenting with chest pain concerning for ischemia, but non-specific or normal ECG findings should be treated for pain and given chewable aspirin. Further assessment is required to determine the next steps in management. Patients who progress, whether with instability or characteristic ECG changes or cardiac biomarkers, will then be managed as in non-STEMI patients. Invasive treatment is usually the next step unless there is a reason not to pursue this treatment. If conservative treatment is provided, patients should have pain treated and remain stable for at least 24 hours before proceeding with functional tests.  

Additional therapies and ECG evaluation

Developing ST elevation will require reperfusion.  In patients suspected of ACS but with nonspecific ECG and negative cardiac biomarkers, rapid evaluation for ischemia can be done non-invasively. Options include CT angiogram, stress echocardiogram, myocardial perfusion image, and cardiac magnetic resonance imaging. Patients with negative tests may be suitable for discharge and can also be predictive for individual future risk of ACS. Evaluation must be continuous as symptoms and signs may change. If a non-cardiac cause is found, the patient should be treated according to the best practices for that disease state. Some notes to remember:

• While normal EKGs make ACS unlikely, it does not rule it out. If pain persists, obtain a repeat ECG to ensure it has not evolved. Ensure a repeat ECG before discharge or hospital admission, and try to obtain it before administering nitroglycerin
• Elevation in cardiac biomarkers can take hours. A follow-up test should be done if the initial test is negative. Typically, this is done 6-8 hours following admission to allow enough time for biomarkers to rise. Also, be aware that presentation at ED does not necessarily indicate time 0 but may be hours or longer since symptom onset. 
• Non-invasive testing such as myocardial perfusion imaging and CT can be useful in diagnosing patients with low to moderate risk of ACS based on findings. Negative results can allow safe discharge. 
• Follow the protocol of your institution in regards to which test should be obtained at what times. Low-risk patients may be discharged with planned follow up in 2-3 days for stress testing, assuming normal EKG, negative cardiac biomarkers, and resolution of pain. High-risk patients should be managed urgently and not subjugated to stress testing. The decision to pursue stress testing in intermediate-risk patients is nuance and requires careful consideration. 

Discharging Patients

Discharge can be acceptable when pain has resolved, or it has been deemed that there is a non-ACS etiology. IF the pain persists, the patient is intermediate in risk and should not be discharged. Typically, patients at low risk should also have two normal EKGs or negative biomarkers separated by at least 6 hours. In this case, discharge can occur with close outpatient follow up. 

Follow up should be within 3 days. Ensure the patient is amenable to follow up and document anticipated compliance and recommendations in the medical record. Additionally, communicate this information to the patient’s outpatient care team if possible.

Alert the patient to activate EMS for symptom recurrence

Hospitals and providers can participate in quality reviews to evaluate the outcomes or complications associated with the management of patients after discharge.