Acute Coronary Syndrome

Pathophysiology

Acute coronary syndrome (ACS) is almost always due to rupture of an atherosclerotic plaque with subsequent partial or complete thrombosis of a coronary artery.1  Acute coronary syndrome can also result from artery dissection, catecholamine surge (Takotsubo cardiomyopathy), aortic valve disease, sympathomimetic agents (cocaine).

Classification of presentation

Angina – exercise or stress related chest pain or pressure that resolves with rest or by removing the offending stimulus, or with nitrate therapy

Unstable angina –  chest pain or pressure that begins at rest or during only minimal exertion and does not resolve with rest or with the use of nitrate therapy

Acute myocardial infarction – significant interruption of one or more coronary arteries resulting in cardiac cell damage / necrosis.  Some patients may develop ECG changes (STEMI) while others may not (non-STEMI)

Clinical Presentation

Classic (patients often present with several/all of the following)

  • Male
  • > 60 years of age
  • Left sided chest pain or pressure
  • Radiation to left arm, neck, jaw
  • Nausea / vomiting
  • Diaphoresis

Atypical (patients often present with one of the following; vague presentation)

  • Female
  • < 55 years of age
  • No chest pain or pressure
  • Dyspnea
  • Unexplained diaphoresis
  • Nausea / vomiting
  • Syncope / near syncope

Assessment

History – symptoms that favor ACS

    • Pressure
    • Burning
    • Indigestion
    • Similar / worse than previous AMI
    • Radiation
    • Exertional
    • Longer duration

History – symptoms that favor something other than ACS

    • Stabbing
    • Sharp
    • Pleuritic
    • Positional
    • Brief episode of pain

Physical

Diagnostic tests

ECG – record a 3-lead and 12-lead ECG tracing.

Management

Goals of prehospital therapy

Therapy

Endpoint of therapy

Transport destination

Transport destination decision tool

Pearls and Pitfalls

  • Don’t rule out ACS solely based on the history.  Patients experiencing ACS can present with right-sided, sharp, stabbing chest pain.
  • Coronary artery disease risk factors are not predictive of ACS
  • Severity of pain is not predictive of ACS versus something non-cardiac
  • Beware of your personal race, gender, and socioeconomic status bias! Cardiovascular disease does not discriminate!
  • A normal, non-diagnostic, or non-STEMI ECG does not rule out ACS

Reference

  1. http://emedicine.medscape.com/article/1910735-overview
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