Cardiac Enzyme Tests: What You Need to Know

Cardiac enzyme tests are essential diagnostic tools used to detect heart damage, particularly in cases of suspected heart attack. These tests measure the levels of specific enzymes and proteins released into the bloodstream when the heart muscle is injured.

Key Enzymes Measured in Cardiac Enzyme Tests

Creatine Kinase (CK) and Its Isoenzymes

One of the primary markers in cardiac enzyme testing is creatine kinase (CK), particularly the CK-MB isoenzyme. This enzyme typically becomes detectable within 2 to 4 hours after heart damage occurs. Levels peak within 1 to 2 days and can remain elevated for up to 3 to 5 days. Due to its sensitivity, increased CK-MB levels often suggest myocardial injury and may prompt further cardiovascular evaluation.

Lactate Dehydrogenase (LDH)

Lactate dehydrogenase is another enzyme that can be elevated following a heart attack. However, it's not exclusive to heart damage, as increased LDH levels can also occur in conditions like hepatitis and liver cirrhosis. Doctors often use LDH in combination with other markers to improve diagnostic accuracy.

Aspartate Aminotransferase (AST)

Aspartate aminotransferase, also known as AST, is an enzyme found in both the heart and liver. Elevated levels can indicate acute myocardial infarction or liver dysfunction, such as hepatitis, cirrhosis, or general liver impairment. While not as specific as CK-MB for heart damage, AST still plays a supportive role in cardiac diagnostics.

Understanding the results of these enzyme tests is crucial for timely diagnosis and treatment of heart-related conditions. If you experience symptoms like chest pain or shortness of breath, your healthcare provider may recommend these tests to assess your heart health.