Acute Coronary Syndrome

Acute Coronary Syndrome,

Acute Coronary Syndrome (ACS) comprises a range of thrombotic coronary artery diseases. It includes unstable angina, and both ST segment elevation and non-ST segment elevation myocardial infarction.[1]


Unstable Angina

Although there is no universally accepted definition of unstable angina,[2] it can be characterized by unexpected and irregular chest pain, and usually occurs while resting.  The most common cause of unstable angina is reduced blood flow to the heart muscle.[3] The reduced blood flow is caused by a blood clot that block an artery either partially or totally.[5]


Myocardial Infarction

A myocardial infarction (heart attack) typically occurs when the blood supply to the heart is blocked for an extended period of time causing the heart muscle to become damaged or die. The blockage may be complete or partial.

A complete blockage of a coronary artery means you suffered from a ‘STEMI’ heart attack. This stands for ST-elevation myocardial infarction.[4]

A partial blockage of a coronary artery means you suffered from an ‘NSTEMI’ heart attack. This stands for non-ST-elevation myocardial infarction.[4]



Chest pain or discomfort may immediately signal to you that something is wrong with your heart. Below are some common signs of an acute coronary syndrome:

  • Shortness of breath
  • Feeling lightheaded or dizzy
  • Nausea
  • Sweating
  • Chest pain or discomfort, which may involve pressure, tightness or fullness
  • Pain or discomfort in one or both arms, the jaw, neck, back or stomach

These symptoms should be taken seriously. If you experience chest pain or other symptoms, please call 9-1-1 immediately.[4]



Treatment for unstable angina requires your healthcare provider to find the blocked part(s) of your arteries. The next step is for your doctor to discuss treatment options with you. Treatment options include:

  • Percutaneous coronary intervention (PCI), which requires using a cardiac catheter with a small inflatable balloon at the tip. The balloon is inflated, squeezing open the fatty plaque deposit located in your artery.[5]
  • Coronary artery bypass surgery, which may be used depending on the extent of your artery blockage and medical history. This treatment option involves using a blood vessel to route blood around the blocked part of your artery, forming a detour.[5]

Treatment for a heart attack will depend on what type of myocardial infarction you experienced. You might receive medicine that helps to dissolve blood clots, have a balloon angioplasty (special tubing with a deflated balloon attached, which is threaded up to your coronary arteries), have surgery, or receive a combination of treatments.[4]

If the hospital determines you had an NSTEMI heart attack, your doctor will typically use one of two treatment strategies:

  • An ischemia-guided strategy, which uses various drugs to inhibit blood clot formation;
  • An early invasive strategy, which starts with the use of various drugs to inhibit blood clot formation, but might also proceed to a medical therapy, a PCI, or coronary artery bypass surgery, followed by certain types of post-hospital care.[4]







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