Identify patients with a possible acute coronary syndrome (ACS) (i.e., ST-elevation myocardial infarction (STEMI), non-ST-elevation myocardial infarction (NSTEMI), or unstable angina).

Stable patients with IHD may experience sudden or acute changes in their clinical status. (i.e., ST-elevation myocardial infarction (STEMI), non-ST-elevation myocardial infarction (NSTEMI), or unstable angina).
The diagnosis of ACS may be suspected on the basis of a compelling clinical history, specific ECG findings and/or elevations in serum markers of cardiac necrosis (e.g., CPK-MB, troponin I, or troponin T). Patients with symptoms that are new, acute, changed or inadequately controlled should be evaluated according to the CORE Module

Symptoms that may represent ischemia

New or worsening symptoms suggestive of myocardial ischemia should prompt consideration of a possible ACS.

• New onset or worsening chest pain, discomfort, pressure, tightness, or heaviness
• "New onset" is defined as chest pain or discomfort being evaluated for the first time or the patient with a complaint of chest pain is new to the clinic.
• "Worsening" is defined as at least a one-class increase (Canadian Cardiovascular Society angina classification) in a patient with known previous symptoms attributed to myocardial ischemia.
• Radiating pain to the neck, jaw, arms, shoulders, or upper back
• Unexplained or persistent shortness of breath
• Unexplained epigastric pain
• Unexplained indigestion, nausea, or vomiting
• Unexplained diaphoresis
• Unexplained weakness, dizziness, or loss of consciousness

Patients with evidence of acute changes in symptoms (within 2 weeks) should be evaluated using the Core Module.

Symptom characteristics that suggest noncardiac pain, (but do not exclude the diagnosis of CAD) include the following:

• Pleuritic pain (i.e., sharp or knife-like pain brought on by respiratory movements or cough)
  
• Primary or sole location of discomfort in the middle or lower abdominal regions
  
• Pain that may be localized at the tip of one finger, particularly over costochondral junctions or the LV apex
  
• Pain reproduced with movement or palpation of the chest wall or arms
  
• Constant pain that lasts for many hours
  
• Very brief episodes of pain that last a few seconds or less
  
• Pain that radiates into the lower extremities

Are Stable Angina Symptoms Adequately Controlled?

The level of symptoms that constitute “adequate control” is highly dependent on several factors:

1. The stage of the CAD
2. Whether or not revascularization is feasible, at an acceptable risk
3. The patient's tolerance or intolerance of anti-anginal drugs
4. Patient preference.

Changes in exercise tolerance and symptoms, over time, are particularly useful in assessing adequacy of control of symptoms of myocardial ischemia. The Canadian Cardiovascular Society (CCS) classification (see Core Module,) is useful for the serial assessment of exercise tolerance and anginal symptoms . Indications for altering therapy and the therapeutic details are presented in Module C, Stable Angina.