Elevated Cardiac Enzymes: Common Causes and What You Need to Know

Cardiac enzymes are a group of proteins that include creatine kinase (CK), creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST). When these enzyme levels rise in the bloodstream, it typically indicates some form of tissue damage. Here are the most common reasons behind elevated cardiac enzyme levels.

Heart-Related Causes of Elevated Cardiac Enzymes

Significantly elevated levels of all four enzymes—especially CK-MB—combined with increased troponin levels, often point to serious heart damage. This pattern is most commonly seen in cases of myocardial infarction (heart attack) or severe viral myocarditis. In these situations, a large number of heart muscle cells die, releasing these enzymes into the blood. Doctors rely heavily on these markers to diagnose acute cardiac events.

Non-Cardiac Causes of High Cardiac Enzymes

Skeletal Muscle Damage and Rhabdomyolysis

When only creatine kinase is elevated and other markers like CK-MB and troponin remain normal, the cause is likely related to skeletal muscle damage rather than heart injury. A growing number of cases are linked to rhabdomyolysis—a condition where muscle fibers break down rapidly. One known risk factor is the consumption of certain foods like crawfish, which have been associated with this syndrome in rare cases. When skeletal muscles are damaged, they release large amounts of CK into the bloodstream, mimicking a cardiac event.

It's important to distinguish between cardiac and non-cardiac causes of enzyme elevation to ensure proper treatment. Physicians often use a combination of blood tests, patient history, and imaging studies to determine the true source of the problem.