Clinical Update: Acute Coronary Syndromes
Acute Coronary Syndrome (ACS) is the term used to describe a variety of cardiac conditions including unstable angina, and myocardial infarction. Unstable angina is a condition characterized by chest pain (angina) and shortness of breath (SOB) that resolves with rest or nitroglycerine administration. Myocardial infarction includes a number of conditions that describe the extent of myocardial damage.
Myocardial infarction is described by the EKG changes and enzyme elevations that occur. There are three major findings that are evaluated:
- ST-segment elevation
- Q-waves
- Blood enzyme levels of CPK-MB and Troponin
Damage to myocardium is classified by the EKG changes that occur. For example, ST-segment elevation MI (STEMI), non-ST-segment elevation MI (NSTEMI), or a Q-wave MI. Injury is confirmed by elevations in Troponin or CPK-MB.
Non-ST-segment elevation MI (NSTEMI) is verified by enzyme elevation, since there are no acute changes. STEMI and Q-wave infarcts are diagnosed by the EKG changes. Q-waves are not an acute finding unless they were not present on a previous EKG.
