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States in which there is painful acute ischaemia of the heart muscle (myocardium). The ischaemia occurs when the coronary arteries cannot supply the heart with sufficient blood and oxygen, because they are narrowed by atherosclerosis. If a thrombus (clot) occludes an artery completely, interruption to the blood supply causes tissue death (a myocardial infarction, MI) and severe, prolonged pain. The distinction between unstable angina (threatened MI) and actual MI is not always clear cut in primary care, which is why the term ACS is preferred. Diagnosis is based on clinical presentation, ECG findings, and blood results. See also Angina pectoris

Symptoms of ACS are:

  • Chest pain (typically crushing central chest pain, sometimes radiating down the inside of the left arm or up to the jaw), which may be accompanied by sweating, nausea, vomiting
  • Sudden onset of breathlessness
  • Clammy skin.

 ! Chest pain is a medical emergency when it is:

  • sustained (lasts at least 20 min)

  • occurring after minimal or no exertion, or at rest (including at night)

  • rapidly worsening, and  not relieved by sublingual GTN (glyceryl trinitrate, prescribed to relieve angina)



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