The significance of cardiomyocytes glutamate concentration in cardiac dysfunction after cardiopulmonary resuscitation

doi:10.3969/j.issn.1002-1949.2015.03.020

Abstract：Objective To observe the concentration of myocardial glutamate changes after cardiopulmonary resuscitation ( CPR ) by the micro -infiltration techniques and its correlation with cardiac dysfunction.Methods Six adult New Zealand rabbits were implanted the micro-dialysis tubes in the cerebral cortex and myocardium to set up cardiac arrest models.When ventricular fibrillation for 5minutes and then restoration of spontaneous circulation (ROSC), we collected dialysate to detected the glutamate concentration, evaluated the left ventricular systolic function by ultrasound and the cerebral cortex and myocardial cell damage by electron microscopy.Results Before ventricular fibrillation, the concentration of glutamate in the cerebral cortex was (76.07 ±8.50)μmmol/L, but it rapidly increased to (107.70 ±7.17)μmmol/L 30 minutes after ROSC and peaked at (139.62 ±15.64)μmmol/L in 2 hours, then followed by a decline and decreased to ( 68.86 ±3.78 )μmmol/L in 3 hours.The concentration of glutamate in myocardium was (87.26 ±14.14)μmmol/L 30 minutes after ROSC, which was significantly increased compared with before ventricular fibrillation (40.33 ±5.39)μmmol/L ( P<0.001).The trend sustained for 1 hour and then declined gradually.After ROSC for 90 min, the concentration fell to ( 47.82 ±6.72 )μmmol/L.Sixty minutes after ROSC, the value of fractional shortening ( FS ) was ( 39.00 ±1.79 )%, left ventricular ejection fraction ( EF ) was ( 47.00 ± 3.90)%, which were both lower than the baseline of (44.83 ±3.25)%and (53.17 ±4.58)%( P=0.001 and 0.008), respcetively.Four hours after ROSC, we saw the mitochondria of rabbit cortex cells swelling obviously, mitochondria ridge blur or even disappear or blank, formation of apoptotic bodies around nuclear and no apoptotic body formation in myocardial cells. Conclusion After rabbit ventricular fibrillation for 6 min and then ROSC, high concentrations of glutamate may have some correlation with cardiac dysfunction.