title: Glycogen phosphorylase isoenzyme BB plasma kinetics is not related to myocardial ischemia induced by exercise stress echo test.
abstract: BACKGROUND
  Glycogen phosphorylase BB (GPBB) is released from cardiac cells during myocyte damage. Previous studies have shown contradictory results regarding the relation of enzyme release and reversible myocardial ischemia. The aim of this study was to determine the plasma kinetics of GPBB as a response to the exercise stress echocardiographic test (ESET), and to define the relationship between myocardial ischemia and enzyme plasma concentrations.
  
  
  METHODS
  We studied 46 consecutive patients undergoing ESET, with recent coronary angiography. In all patients, a submaximal stress echo test according to Bruce protocol was performed. Concentration of GPBB was measured in peripheral blood that was sampled 5 min before and 10, 30 and 60 min after ESET.
  
  
  RESULTS
  There was significant increase of GPBB concentration after the test (p=0.021). Significant increase was detected 30 min (34.9% increase, p=0.021) and 60 min (34.5% increase, p=0.016) after ESET. There was no significant effect of myocardial ischemia on GPBB concentrations (p=0.126), and no significant interaction between sampling intervals and myocardial ischemia, suggesting a similar release profile of GPBB in ischemic and non-ischemic conditions (p=0.558). Patients in whom ESET was terminated later (stages 4 or 5 of standard Bruce protocol; n=13) had higher GPBB concentrations than patients who terminated ESET earlier (stages 1, 2 or 3; n=33) (p=0.049). Baseline GPBB concentration was not correlated to any of the patients' demographic, clinical and hemodynamic characteristics.
  
  
  CONCLUSIONS
  GPBB plasma concentration increases after ESET, and it is not related to inducible myocardial ischemia. However, it seems that GPBB release during ESET might be related to exercise load/duration.
authors.forename: Milan
authors.initials: M
authors.lastname: Dobric
authors.forename: Vojislav
authors.initials: V
authors.lastname: Giga
authors.forename: Branko
authors.initials: B
authors.lastname: Beleslin
authors.forename: Svetlana
authors.initials: S
authors.lastname: Ignjatovic
authors.forename: Ivana
authors.initials: I
authors.lastname: Paunovic
authors.forename: Jelena
authors.initials: J
authors.lastname: Stepanovic
authors.forename: Ana
authors.initials: A
authors.lastname: Djordjevic-Dikic
authors.forename: Jelena
authors.initials: J
authors.lastname: Kostic
authors.forename: Ivana
authors.initials: I
authors.lastname: Nedeljkovic
authors.forename: Milan
authors.initials: M
authors.lastname: Nedeljkovic
authors.forename: Milorad
authors.initials: M
authors.lastname: Tesic
authors.forename: Marijana
authors.initials: M
authors.lastname: Dajak
authors.forename: Miodrag
authors.initials: M
authors.lastname: Ostojic
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D025401:Echocardiography, Stress; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D024981:Glycogen Phosphorylase / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood* / Q000201:enzymology; D012107:Research Design; D013997:Time Factors
chemical_list: D024981:Glycogen Phosphorylase; C528446:glycogen phosphorylase BB, human