Acute coronary syndrome is the name given to types of coronary disease that are associated with a sudden blockage in the blood supply to your heart. Some people have symptoms before they have acute coronary syndrome, but you may not have symptoms until the condition occurs. Some people never have any symptoms. Changes caused by acute coronary syndrome can be seen on an electrocardiogram (ECG) and in blood tests. Acute coronary syndrome is defined by the location of the blockage, length of time the artery is blocked and amount of damage and is defined as:
- Unstable angina: This may be a new symptom or can happen if you have stable angina that changes to unstable angina. You may start to have angina more often, when you are resting, or it may be worse or last longer. The condition can lead to a heart attack. If you have unstable angina, you will need medication, such as nitroglycerin or a procedure to correct the problem.
- Non-ST segment elevation myocardial infarction (NSTEMI): This is a type of heart attack (MI) that does not cause major changes on an ECG. But, a blood test will show that there is damage to your heart muscle.
- ST segment elevation myocardial infarction (STEMI): This type of heart attack (MI) is caused by a sudden blockage of the blood supply to the heart.
These are life-threatening conditions that require emergency medical care.