KN-93, A CaMKII inhibitor, suppresses ventricular arrhythmia induced by LQT2 without decreasing TDR


Abnormal enhanced transmural dispersion of repolarization (TDR) plays an important role in the maintaining of the severe ventricular arrhythmias such as torsades de pointes (TDP) which can be induced in long-QT (LQT) syndrome. Taking advantage of an in vitro rabbit model of LQT2, we detected the effects of KN-93, a CaM-dependent kinase (CaMK) II inhibitor on repolarization heterogeneity of ventricular myocardium. Using the monophasic action potential recording technique, the action potentials of epicardium and endocardium were recorded in rabbit cardiac wedge infused with hypokalemic, hypomagnesaemic Tyrode’s solution. At a basic length (BCL) of 2000 ms, LQT2 model was successfully mimicked with the perfusion of 0.5 μmol/L E-4031, QT intervals and the interval from the peak of T wave to the end of T wave (Tp-e) were prolonged, and Tp-e/QT increased. Besides, TDR was increased and the occurrence rate of arrhythmias like EAD, R-on-T extrasystole, and TDP increased under the above condition. Pretreatment with KN-93 (0.5 μmol/L) could inhibit EAD, R-on-T extrasystole, and TDP induced by E-4031 without affecting QT interval, Tp-e, and Tp-e/QT. This study demonstrated KN-93, a CaMKII inhibitor, can inhibit EADs which are the triggers of TDP, resulting in the suppression of TDP induced by LQT2 without affecting TDR.

DOI: 10.1007/s11596-013-1172-1

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@article{2013KN93AC, title={KN-93, A CaMKII inhibitor, suppresses ventricular arrhythmia induced by LQT2 without decreasing TDR}, author={Wen-long Wang 王文隆 and Shuang-shuang Zhang 张双双 and Jie Deng 邓 洁 and Jun-yan Zhao 赵俊燕 and Chong-qiang Zhao 赵崇强 and Li Lin 林 立 and Cun-tai Zhang 张存泰 and Jia-gao Lv 吕家高}, journal={Journal of Huazhong University of Science and Technology [Medical Sciences]}, year={2013}, volume={33}, pages={636-639} }