Submitted to: American Journal of Emergency Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/1997
Publication Date: N/A
Interpretive Summary: There are currently several different diagnostic laboratory tests conducted on people who are suffering symptoms of a heart attack. Emergency room physicians typically will evaluate serum levels of the enzyme Creatinine Kinase (CK) and its isoform Creatinine Kinase - MB(CK-MB) High levels of these enzymes tend to indicate muscle injury, particularly heart muscle injury. Relative levels of the various white blood cells in a patient's blood are also used to indicate cardiac status. This research was conducted to determine enzyme and blood cell levels in healthy volunteers following strenuous exercise. Total CK, CK-MB, and differential white blood cell counts were determined following a 20 minute bench stepping exercise in 21 males, ranging in age from 30 to 45 years of age. When each different diagnostic test was evaluated individually, several results were above the cutoff indicating a heart attack. When both CK and white cell count results were combined in determining outcome, false-positive results were eliminated. These results show that if emergency room doctors utilize several tests in diagnosis they can reduce the incidence of misdiagnosis of heart attacks.
Technical Abstract: The purpose of this investigation was to determine the response of three parameters utilized in assessment of AMI, following a single bout of eccentric exercise designed to elicit skeletal muscle injury. Total CK, CK-MB, and the leukocyte differential were determined following a 20 minute bench stepping exercise in 21 males ranging in age from 30-45 years. Comparison of several criteria showed that utilization of CK-MB or the relative lymphocyte percentage alone resulted in 11% and 1.7%, respectively of data collection points exceeding cutoff values suggestive of AMI. However, the utilization of both parameters in combination completely eliminated false-positive results with no data collection points meeting the criterion. It is thus suggested that CK-MB activity in conjunction with the relative lymphocyte percentage may not only provide incremental value in the detection of AMI but reduce the incidence of misdiagnosis associated with exercise.