Lu Yen-Yu, Cheng Chen-Chuan, Tsai Chin-Feng, Lin Yung-Kuo, Lee Ting-I, Chen Yao-Chang, Chen Shih-Ann, Chen Yi-Jen
Division of Cardiology, Sijhih Cathay General Hospital, New Taipei City, Taiwan.
School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan.
Clin Sci (Lond). 2017 Jun 7;131(12):1317-1327. doi: 10.1042/CS20170121. Print 2017 Jun 1.
Ventricular arrhythmias commonly arise from the right (RVOT) and left ventricular outflow tracts (LVOT) in patients without structural heart disease. Heart failure (HF) significantly increases the risk of ventricular arrhythmias. The regional differences and how HF affects the electrophysiological characteristics of RVOT and LVOT cardiomyocytes remain unclear. The whole-cell patch-clamp technique was used to investigate the action potentials and ionic currents in isolated single RVOT and LVOT cardiomyocytes from control rabbits and rabbits with HF induced by rapid ventricular pacing. Comparison with control LVOT cardiomyocytes showed that control RVOT cardiomyocytes have a shorter action potential duration (APD), smaller late Na currents (), larger transient outward () and larger delayed rectifier K currents (), but had similar L-type Ca currents () and Na/Ca exchanger (NCX) current. HF increased APD, and NCX, but decreased and in RVOT cardiomyocytes. In contrast with this, HF decreased APD and , but increased and in LVOT cardiomyocytes. In conclusion, RVOT and LVOT cardiomyocytes had distinctive electrophysiological characteristics. HF differentially modulates action potential morphology and ionic currents in RVOT and LVOT cardiomyocytes.
在无结构性心脏病的患者中，室性心律失常通常起源于右心室流出道（RVOT）和左心室流出道（LVOT）。心力衰竭（HF）会显著增加室性心律失常的风险。区域差异以及HF如何影响RVOT和LVOT心肌细胞的电生理特性仍不清楚。采用全细胞膜片钳技术研究了来自对照兔和快速心室起搏诱导的HF兔的离体单个RVOT和LVOT心肌细胞的动作电位和离子电流。与对照LVOT心肌细胞相比，对照RVOT心肌细胞的动作电位时程（APD）较短，晚期钠电流（）较小，瞬时外向电流（）较大，延迟整流钾电流（）较大，但L型钙电流（）和钠/钙交换体（NCX）电流相似。HF增加了RVOT心肌细胞的APD、和NCX，但降低了和。与此相反，HF降低了LVOT心肌细胞的APD和，但增加了和。总之，RVOT和LVOT心肌细胞具有独特的电生理特性。HF对RVOT和LVOT心肌细胞的动作电位形态和离子电流有不同的调节作用。
