Markers of myocardial injury will continue to play an essential role in the
assessment and management of patients presenting within the spectrum of ac
ute coronary syndromes, a term representing the continuum of acute myocardi
al ischemia ranging from angina through Q-wave myocardial infarction. Coron
ary artery lesion instability can be detected by markers of plaque inflamma
tion and disruption, platelets reactivity, and thrombosis. When myocardial
injury occurs with severe impairment of coronary blood flow, several marker
s are released from the damaged myocyte. For many years, creatine kinase-MB
isoenzyme has been the conventional marker for myocardial infarction. Desp
ite its inadequate sensitivity and specificity for myocardial injury, creat
ine kinase-MB remains an essential component in assessing reinfarction or i
nfarct extension, as well as in monitoring reperfusion after thrombolytic t
herapy when combined with myoglobin. Among the many cardiac markers for myo
cardial necrosis, cardiac troponins possess superior sensitivity and specif
icity for the detection of myocardial injury. In addition to their superior
performance in detecting minor myocardial damage, cardiac troponins can be
useful in detecting perioperative myocardial infarction, infarct size, imp
roving risk stratification, and facilitating therapeutic decision making in
patients with acute coronary syndromes.