Originalni ~lanci/ Original articles GLYCOGEN PHOSPHORYLASE ISOENZYME BB AS A MARKER OF MYOCARDIAL STUNNING IN WATER POLO PLAYERS GLIKOGEN FOSFORILAZA TIP BB KAO MARKER OŠAMU)ENJA MIOKARDA KOD VATERPOLISTA

Background: In past years, several studies have suggested myocardial damage after extreme exercise due to increased post exercise levels of cardiac markers which return to baseline levels within 24 hours. Recently, the importance of the process labeled as myocardial “stunning” caused by ischemia or coronary vasospasm which is transient in nature and does not result in necrosis and permanent cellular damage has been emphasized. This study was performed to test if this extremely strenuous sport is hazardous to cardiovascular health of adolescent male water polo players. To this end, we measured serum concentration of the early marker of myocardial ischemia glycogen phosphorylase isoenzyme BB (GP-BB). Methods: Total of 20 water polo players was studied. They were randomly divided in two groups: exercise group and non-exercise that served as a control group. GP-BB concentration was measured at different time points: basaline, and 1, 30 and 60 minutes following. exercise. Results: Increased GP-BB concentration was found in 40% of water polo players in 1 and 30 minutes post exercise, but in only 10% one hour later. Obtained concentration 1 and 30 minutes following exercise significantly positively correlated (r=0.895;p<0.001) as well as concentrations at 30 and 60 minutes (r=0.697; p<0.03). Conclusion: Glycogen phosphorylase isoenzyme BB could be a good marker of myocardial stunning caused by ischemia or coronary vasospasm which is transient in nature and does not result in necrosis and permanent cellular damage in water polo players.