A description of cardiac biomarkers and their use requires the knowledge of several terms. In Table 1, these terms and their definitions are listed.
Table 1. Terminology. | Term | Definition |
| Acute Coronary Syndrome (ACS) | This syndrome is a broader term that includes all ischemic events that can occur in the heart. Ischemia is defined simply as inadequate blood supply to an organ (in this case, the heart). These ischemic events range from angina (where there is no cell death or reversible cell injury) to an AMI with large areas of cell necrosis (dead cardiac myocytes). A continuum of events that are involved in ACS is illustrated on the page that follows this glossary of terms. |
| Angina | Angina refers to chest pain caused by an inadequate supply of oxygen to heart myocardium. It is synonymous with angina pectoris (pectoris refers to the chest). |
| Acute Myocardial Infarction (AMI) | Commonly referred to as a heart attack, an AMI is a sudden loss of blood flow, and thus oxygen, to the muscle tissue of the heart (the myocardium). This causes necrosis of myocardial tissue. It is most often caused by the narrowing of coronary arteries due to atherosclerosis, a thrombus, or dislodged plaque material. |
| Congestive Heart Failure (CHF) | CHF is usually a left ventricular dysfunction resulting from aging, hypertension, atherosclerosis, or muscle damage from an AMI or repeated AMIs. In CHF, the heart is not able to effectively pump blood through its chambers and to the rest of the body. Fluid accumulates in the lungs and tissues causing edema because less blood leaves through the arteries than enters the heart from the veins. |
| Electrocardiogram (ECG or EKG) | An ECG or EKG refers to the tracings of electrical currents that pass through the myocardium. Heart contractions are stimulated by electrical currents from the atria. In areas of myocyte necrosis, the current does not pass through normally and the tracings will reflect this with abnormal patterns. |
| Infarction | An infarction is an area of tissue death that occurs due to a lack of oxygen. Clogging of an artery will cause dead muscle tissue downstream of the blockage. Infarctions are localized areas of necrosis. |
