Low Risk Acute Coronary Syndrome Management

Aka: Low Risk Acute Coronary Syndrome Management, Non-diagnostic Electrocardiogram Protocol, Non-diagnostic EKG Protocol, Atypical Chest Pain

1. See Also
   1. Immediate MI Management
2. Indications: Immediate MI Management in low risk cases
   1. ST Depression 0.5 to 1.0 mm
   2. T Wave inversion or flattening
      1. Leads with dominant R Wave
   3. Normal Electrocardiogram
3. Contraindications: Moderate Risk patient
   1. See Moderate Risk Acute Coronary Syndrome Management
   2. Criteria
      1. Unstable Angina
      2. New Onset Angina
      3. Troponin Increased
4. Management: Low Risk
   1. Aspirin 325 mg PO qd
   2. Initial Evaluation
      1. Serum Cardiac Markers
         1. Troponin (consider repeat in 6 hours)
         2. CK-MB
      2. Repeat Electrocardiogram
      3. Continuous ST segment monitoring
      4. Assess Angina Diagnosis likelihood
      5. Consider Chest Pain differential diagnosis
   3. Signs of Myocardial Ischemia or Myocardial Infarction
      1. See Myocardial Ischemia Protocol
      2. Consider MI Adjunctive Therapy
      3. Continuous Cardiac Monitoring (follow ST segment)
      4. Serial Cardiac Markers
         1. Consider Troponin 6 hours after first Troponin
            1. Troponin I over 1.0 suggests Acute MI
         2. Serial Creatine Phosphokinase every 6 hours x3
            1. Fractionate to CK-MB only if CPK increased
            2. CK-MB over 5% of total CPK suggests Acute MI
      5. Imaging studies
         1. Stress Echocardiogram
         2. Perfusion Radionuclide scan
   4. No Signs Myocardial Ischemia or Myocardial Infarction
      1. Assess adverse event risk (see Unstable Angina Risk)
      2. Low risk patients do not require telemetry
         1. Goldman risk score <8% and
         2. Troponin I <0.3 ng/ml and
         3. CK-MB <5 ng/ml
         4. Hollander (2004) Ann Emerg Med 43:71-6
      3. Disposition based on Unstable Angina Risk
         1. High risk for adverse event in near future
            1. See Myocardial Inschemia Protocol
            2. Treat same as signs of Myocardial Ischemia above
         2. Intermediate risk for adverse event in near future
            1. Continuous Cardiac Monitoring (follow ST segment)
            2. Troponin 6 hours after first Troponin
               1. Troponin I over 1.0 suggests Acute MI
            3. Exercise Stress Test if Troponin negative
               1. Positive test treated as high risk above
               2. Negative test treated as low risk below
         3. Low risk for adverse event in near future
            1. Discharge from Emergency Department
            2. Close follow-up with primary physician
            3. Discuss warning signs
            4. Outpatient Exercise Stress Testing