Effects of different concentrations of sevoflurane on monophasic action potential of myocardium of ische-mia-reperfusion / 临床麻醉学杂志

ABSTRACT

Objective To study the effects of different concentrations of sevoflurane on monophasic action potentials (MAPs)of three-layer myocardium of ischemia reperfusion in isolated rat hearts.Methods Thirty-two healthy SD male rats,weighing 280-320 g,were randomly divided into four groups after successful preparation of langendorff isolated heart perfusion model and 1 5 min perfusion and balance of K-H fluid.In the ischemia-reperfusion group(group IR),K-H fluid perfusion was stopped and balanced for 15 min and cardiac arrest was induced for 60 min with the injection of Thomas solution (4℃,20 ml/kg)while the heart was protected by the low temperature Thomas so-lution (4℃)around it.Reperfusion of Thomas solution (4℃,10 ml/kg)was performed for 30 min and the heart was resuscitated by the perfusion of K-H fluid for 60 min.In the 0.5 MAC sevoflurane group (group Sev0.5 ),K-H fluid contained 0.5 MAC sevoflurane and other procedures were the same as in group IR.1.0 MAC sevoflurane group (group Sev1.0 ),K-H fluid contained 1.0 MAC sevoflurane and other procedures were the same as in group IR.2.0 MAC sevoflurane group (group Sev2.0),K-H fluid contained 2.0 MAC sevoflurane and other procedures were same as in group IR. HR,MAPs including time course (MAPD50,MAPD90)and MAP amplitude of endocardium,mid-layer myodardium and epicardium was recorded at the time of continuous balance perfusion for 1 5 min (T0),continuous perfusion for 15 min (T1),reperfusion for 15 min (T2)and 30 min (T3). Results Compared with T0and T1,HR was slower at T2and T3(P<0.05);Compared with group IR at T2and T3,HR in group Sev0.5 and group Sev1.0 was higher,that in group Sev2.0 was slower P<0.05);At T2,arrhythmia was observed in 6 rats in group IR,while arrhythmia was observed in 1 rats in group Sev0.5 ,and arrhythmia was observed in 2 rats in group Sev1.0 and arrhythmia was observed in 1 rats in group Sev2.0;Compared with group IR at T3,MAPD50in group Sev0.5 was shorter in three sites(P<0.05);Compared with group IR at T3,MAPD90in other three groups was shorter.Conclusion Different concentrations of sevoflurane can shorten MAPD90of MAPs,and the effects don＇t depend on the concertrations of sevoflurane when it changes from 0.5 MAC to 2.0 MAC;which may be the mechanism of decreased arrhythmias risk caused by sevoflurane.