What diseases can be detected by cardiac enzyme tests?
Dec 15, 2020
Source: Cainiu Health
Dr. Liu Xiangfei
Introduction
What conditions can cardiac enzyme tests detect?
Cardiac enzyme assays are clinically used primarily to diagnose acute coronary syndrome and help determine whether a patient has experienced an acute myocardial infarction. In addition to acute myocardial infarction, abnormal cardiac enzyme levels may also occur in patients with autoimmune diseases affecting the heart.
Cardiac enzymes refer to a group of enzymes naturally present in cardiac muscle tissue, including aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and its isoenzymes, and alpha-hydroxybutyrate dehydrogenase (HBDH). During acute myocardial infarction (AMI), necrotic cardiomyocytes release multiple intracellular enzymes into the bloodstream; thus, measuring serum cardiac enzyme levels holds clinical value for diagnosing AMI and evaluating the efficacy of thrombolytic therapy.
What Diseases Can Cardiac Enzyme Testing Detect?
Cardiac enzyme assays are clinically employed primarily for diagnosing acute coronary syndrome (ACS) and helping confirm whether an acute myocardial infarction has occurred. While cardiac enzyme abnormalities most commonly occur in AMI, they may also be observed in other conditions, including autoimmune disorders, acute heart failure, hypothyroidism, skeletal muscle injury, and rhabdomyolysis.
Specific biomarkers such as cardiac troponin I (cTnI) or cardiac troponin T (cTnT) exhibit relatively high diagnostic specificity for AMI. Moreover, elevated cTnI or cTnT levels in patients with acute heart failure often indicate a poor prognosis; therefore, routine measurement of these markers is recommended in such patients. Creatine kinase-MB (CK-MB), another key cardiac enzyme, not only aids in confirming AMI but also helps estimate the extent (i.e., infarct size) of myocardial damage.
Causes of Elevated Cardiac Enzymes
1. Myocarditis: Given the numerous factors influencing cardiac enzyme profiles, many hospitals now rely on cardiac troponin measurements to assist in diagnosing myocarditis. In most pediatric cases, cardiac enzyme levels are typically 2–3 times higher than the normal reference range.
2. Myocardial Injury: Cardiac enzyme testing mainly serves to detect myocardial ischemia/necrosis or increased cardiomyocyte membrane permeability. Elevated cardiac enzyme levels suggest myocardial injury—often attributable to viral infection. Patients should undergo regular follow-up testing and ensure adequate rest.
3. Myocardial Ischemia: An elevated cardiac enzyme profile may reflect myocardial ischemia and warrants further diagnostic evaluation.
The above outlines the clinical conditions that cardiac enzyme testing can help identify. We hope this information proves helpful.
