Effect of down-regulation of IKs repolarization-reserve on ventricular arrhythmogenesis in a guinea pig model of cardiac hypertrophy
10.11817/j.issn.1672-7347.2018.04.015
- VernacularTitle:IKs复极储备下调对心肌肥厚豚鼠室性心律失常发生的影响
- Author:
Hegui WANG
1
;
Ting HUANG
;
Zheng WANG
;
Nannan GE
;
Yongsheng KE
Author Information
1. 皖南医学院附属弋矶山医院心血管内科
- Keywords:
cardiac hypertrophy;
rapidly activated delayed rectifier potassium channel;
slowly activated delayed rectifier potassium channel;
repolarization reserve;
ventricular arrhythmias
- From:
Journal of Central South University(Medical Sciences)
2018;43(4):428-433
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To observe the changes of rapidly activated delayed rectifier potassium channel (IKs) and slowly activated delayed rectifier potassium channel (IKs) in cardiac hypertrophy and to evaluate the effects of IKs and IKs blocker on the incidence ofventricular arrhythmias in guinea pigs with left ventricular hypertrophy (LVH).Methods:Guinea pigs were divided into a sham operation group and a left ventricular hypertrophy (LVH) group.LVH model was prepared.Whole cell patch-clamp technique was used to record IKr and IKs tail currents in a guinea pig model with LVH.The changes of QTc and the incidence rate of ventricular arrhythmias in LVH guinea pigs were observed by using the IKr and IKs blockers.Results:Compared with cardiac cells in the control group,the interventricular septal thickness at end systole (IVSs),left ventricular posterior wall thickness at end systole (LVPWs),QTc interval and cell capacitance in guinea pigs with LVH were significantly increased (P＜0.05);while IKs densities were significantly reduced [+60 mV:(0.36±0.03) pA/pF vs (0.58±0.05) pA/pF,P＜0.01].However,LVH exerted no significant effect on IKr densities.IKr blocker markedly prolonged the QTc interval (P＜0.01) and increased the incidence of ventricular arrhythmias in guinea pigs with LVH compared with the control guinea pigs.In contrast,IKs blocker produced modest increase in QTc interval in guinea pigs of control group with no increase in LVH animals.IKs blocker did not induce ventricular arrhythmias incidence in either control or LVH animals.Conclusion:The cardiac hypertrophy-induced arrhythmogenesis is due to the down-regulation of IKs.
