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Acute coronary syndrome (ACS) encompasses unstable angina, ST-segment elevation myocardial infarction (STEMI), and non–ST-segment elevation myocardial infarction (NSTEMI). It is the symptomatic cardiac end product of cardiovascular disease (CVD) resulting in reversible or irreversible cardiac injury and even death.


The diagnosis of ACS requires two of the following: ischemic symptoms, diagnostic electrocardiogram (ECG) changes, or elevated serum marker of cardiac injury.

A. Symptoms

By themselves, signs and symptoms are not enough to diagnose or rule out ACS, but they start the investigatory cascade. Having known risk factors for coronary artery disease (CAD) (Table 20–1) or prior ACS increases the likelihood of ACS. Up to one-third of people with CAD progress to ACS with chest pain. Although chest pain is the predominant symptom of ACS, it is not always present. Symptoms include the following:

Table 20–1.Risk factors for coronary artery disease (CAD).

  • Chest pain

    • Classic: substernal pain that occurs with exertion and alleviates with rest (in a person with a history of CAD, this is called “typical” or “stable” angina)

    • Dull, heavy pressure in or on the chest

    • Sensation of a heavy object on the chest

    • Initiated by stress, exercise, large meals, sex, or any activity that increases the body’s demand on the heart for blood

    • Lasting >20 minutes

    • Change in quality or quantity over the preceding 24 hours

    • Radiating to the back, neck, jaw, left arm or shoulder, or both arms

    • Accompanied by feeling clammy or sweaty

    • Associated with sensation of dry mouth (women)

    • Not affected by inspiration

    • Not reproducible with chest palpation

    • Similar to a prior myocardial infarction (MI)

    • Left arm pain without chest pain

  • Right-sided chest pain, occasionally

    • More common in African American patients

  • Pain high in the abdomen or chest, nausea, and back pain; can occur in anyone but are more common in women

  • Extreme fatigue or edema after exercise

  • Indigestion or dyspepsia

  • Shortness of breath

    • This can be the only sign in the elderly

    • More common in ...

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