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Heart Attack

Coronary Arteries Completely Blocked

A heart attack occurs when the coronary arteries become completely blocked by plaque rupture and thrombosis (blood clot formation), impeding blood flow to the heart muscle beyond this blockage.

Heart Muscle Can Become Damaged and Die

If the flow of blood isn't restored quickly, the section of heart muscle becomes damaged from lack of oxygen and begins to die.

Heart Attack


Symptoms of a heart attack include:

  • Crushing pressure in your chest
  • Pain in your shoulder or arm
  • Shortness of breath
  • Sweating

Two Forms of Myocardial Infarctions

Heart attacks are also known as myocardial infarctions (MI). Heart attacks come in two forms.

Non-ST Segment Elevation Myocardial Infarction

Non-ST segment elevation myocardial infarction (NSTEMI) or "non-Q-wave MI" does not cause typical changes on an electrocardiogram (ECG) test. But chemical markers in the blood show that damage has been done to the heart muscle.

ST Segment Elevation Myocardial Infarction

ST segment elevation myocardial infarction (STEMI) or "Q-wave MI" is caused by a more prolonged period of blocked blood supply. It affects a larger area of the heart muscle and causes changes on the ECG as well as in chemical markers in the blood. Patients with ST segment elevation heart attacks have a worse prognosis, as these are more severe.

Call 911 Immediately

If you suspect you are having a heart attack, call 911 immediately.

Contact Information

Cardiovascular Medicine
Division of the CardioVascular Institute
Beth Israel Deaconess Medical Center
330 Brookline Avenue
Boston, MA 02215