Effects of hypothermia combined with dexmedetomidine on myocardial monophasic action potentials in isolated rabbit hearts
10.3760/cma.j.issn.0254-1416.2015.04.007
- VernacularTitle:低温联合右美托咪定对兔心肌单相动作电位的影响
- Author:
Hui LI
;
Hong GAO
;
Yan ZHAO
;
Juan LONG
;
Kaiqiang ZHANG
;
Yanqiu LIU
- Publication Type:Journal Article
- Keywords:
Hypothermia,induced;
Dexmedetomidine;
Action potentials;
Intraoperative complications
- From:
Chinese Journal of Anesthesiology
2015;35(4):419-422
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effects of hypothermia combined with dexmedetomidine on myocardial monophasic action potentials (MAPs) in isolated rabbit hearts.Methods Adult rabbits,weighing 2.0-2.5 kg,were heparinized and anesthetized with pentobarbital sodium 30 mg/kg.Their hearts were rapidly removed and retrogradely perfused in a Langendorff apparatus at 37 ℃.Eighteen hearts were randomly divided into 3 groups (n =6 each) using a random number table:control group (group C),hypothermia group (group H),and hypothermia+dexmedetomidine group (group HD).The hearts were continuously perfused for 60 min with 37 ℃ K-H solution in group C,with 32 ℃ K-H solution in group H,or with 32 ℃ K-H solution containing dexmedetomidine 25 ng/ml in group HD.At the end of equilibration (T0) and at 15,30 and 60 min of perfusion with K-H solution,HR and MAPs of left ventricular epicardium,mid-myocardium and endocardium were recorded.MAP duration at 50％ repolarization (MAPD50) and at 90％ repolarization (MAPD90),monophasic action potential amplitude (MAPA) and maximal velocity (Vmax) were calculated.Results Compared with group C,HR was significantly decreased,and MAPD50 and MAPD90 were prolonged at each time of perfusion with K-H solution in H and HD groups.There was no significant difference in HR,MAPD50 and MAPD90 between H group and HD group.There was no significant difference in MAPA and Vmax between the three groups.Conclusion Hypothermia combined with dexmedetomidine can lead to prolongation of myocardial repolarization,and dexmedetomidine exerts no effect on hypothermia-induced change in MAPs in isolated rabbit hearts.
