Contributed by Sanja Dacic, MD, PhD and Mohamed A Virji, MD, PhD
Published on line in January 1999
Clinical decisions for potential acute myocardial infarction (AMI) patients traditionally rest primarily on a patient's presenting symptoms and electrocardiogram (ECG) findings, with the subsequent diagnosis depending on serial results for enzymes drawn over a 24-hour period. The diagnosis of AMI is particularly difficult in the elderly and diabetics. The sensitivity of initial ECG is about 50% for detecting myocardial damage, thus the use of biochemical markers may contribute to the early diagnosis and treatment. At the same time, it is recognized that there is often no need at all for the use of any biochemical marker when the clinical diagnosis is unequivocal, other than for confirmation of clinically suspected diagnosis, prognosis, monitoring thrombolytic therapy, or diagnosing reinfarction.
At this time there is no consensus as to which biochemical markers should be used universally in patients with myocardial ischemia. Rational use of various currently available biochemical markers should be guided by the clinical situation. Use of those laboratory tests in various clinical settings is illustrated by the two clinical cases that are presented here.