engleski

Kinetics of glycogen phosphorylase BB after stress testing‑induced myocardial ischemia

Introduction: Glycogen phosphorylase BB (GPBB) is a potentially valuable biochemical marker in myocardial ischemia. The aim of our study was to define the kinetics and diagnostic value of GPBB in diagnosing myocardial ischemia using a model of transient ischemia induced by ergometric stress testing. Methods: The study included 30 subjects with a positive ergometric test result and coronary artery disease confirmed by coronary angiography (ischemic group), and 15 healthy volunteers with a negative ergometric test result (control group). Plasma GPBB concentration was measured basally at one point, prior to the stress test, and at 9 points after the stress test for the next 6 h. Results: The kinetics of GPBB was significantly different between the ischemic group and the control group (p < 0.001). Analysis of the GPBB dynamics curve in the ischemic group shows a statistically significant difference in comparison with the basal concentration in the measurement taken after 0.5 h, and is also observed in the measurements taken 1 and 1.5 h after ergometric stress testing, while disappearing in the measurement taken after 2 h (Fig. 1). Analysis of GPBB increase in the ischemic group showed that the median of the highest absolute GPBB concentrations was statistically significantly higher in comparison with the control group (9.34 ng/ml in the ischemic group ; 5.90 ng/ml in the control group). Therefore, a GPBB concentration of 6.775 ng/ml was determined as the optimal cut-off value for predicting myocardial ischemia, with 83% sensitivity and 87% specificity. Conclusions: GPBB is a valuable biochemical marker in myocardial ischemia, with high sensitivity and specificity. The optimal timeframe for sampling and predicting recent myocardial ischemia by means of determining GPBB concentration is between 0.5 and 1.5 h after the onset of ischemia.

glycogen phosphorylase BB ; ergometric test ; myocardial ischemia

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