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Creatine kinase and creatine kinase B-subunit in stable and unstable angina pectoris
Insights
Repetitive cardiac ischemia may cause cell damage. This study found creatine kinase (CK) levels suggest slight enzyme release after repeated ischemic attacks, but CK-B levels were inconclusive for unstable angina patients.
Area of Science:
- Cardiology
- Biochemistry
- Enzyme kinetics
Background:
- Repetitive ischemic episodes can potentially lead to cumulative myocardial cell damage and enzyme release.
- Understanding enzyme variations, specifically creatine kinase (CK) and creatine kinase B-subunit (CK-B), is crucial for assessing cardiac injury.
- Distinguishing between different cardiac conditions based on enzyme markers requires careful analysis of signal-to-noise ratios.
Purpose of the Study:
- To investigate the theory that repetitive ischemic episodes cause cumulative myocardial cell damage and enzyme release.
- To analyze plasma CK and CK-B concentrations in patients with acute chest pain but without acute myocardial infarction (AMI).
- To evaluate enzyme variations across different patient groups: non-ischaemic heart disease (non-IHD), stable angina pectoris (SAP), and unstable angina pectoris (UAP).
Main Methods:
- Studied forty-eight patients admitted with acute chest pain.
- Classified patients into four groups: non-IHD (14), SAP (17), UAP (10), and those who developed AMI (7).
- Measured plasma concentrations of creatine kinase (CK) and creatine kinase B-subunit (CK-B) to assess enzyme release and variability.
Main Results:
- Enzyme variation in non-IHD patients established a baseline 'background noise'.
- Patients with stable angina pectoris (SAP) showed enzyme signals similar to the background noise for both CK and CK-B.
- In unstable angina pectoris (UAP), CK-B levels matched background noise, while CK levels were elevated, suggesting slight enzyme release from repeated ischemia, though CK-B's poor signal-to-noise ratio limited its utility.
Conclusions:
- The behavior of CK-B did not support the theory of cumulative damage in UAP due to low analytical sensitivity and poor signal-to-noise ratio.
- Findings for CK suggest that repeated ischemic attacks result in slight enzyme release, indicating potential, albeit minor, myocardial cell damage.
- Further research with enhanced analytical sensitivity may be needed to fully elucidate the role of CK-B in diagnosing cardiac ischemia.
Abstract:
Repetitive ischaemic episodes may have a cumulative effect leading to irreversible myocardial cell damage with enzyme release. Using plasma creatine kinase (CK) and creatine kinase B-subunit (CK-B) concentrations this theory has been tested in forty-eight patients admitted with acute chest pain, but without ECG signs of acute myocardial infarction (AMI). The patients were classified into four groups: Fourteen patients with non-ischaemic heart disease (non-IHD), seventeen with stable angina pectoris (SAP), ten with unstable angina pectoris (UAP), and seven patients who developed AMI during the study period. The enzyme variation in non-IHD delineates the background noise, and the increased variability in AMI indicates the full scale of the enzyme signals in cases of irreversible cell damage. Patients with SAP have the same enzyme signal as the background noise in respect of both CK and CK-B. However, in UAP the signal of CK-B equals the background noise, whereas the CK signal is separated from the latter. The reason may be that the signal to noise ratio of CK-B is poor and the analytical sensitivity low. Therefore, the behaviour of CK-B in this study does not support the above theory although our findings for CK indicate that the consequence of repeated ischaemic attacks is slight enzyme release.