右室流出道起搏现状

右室心尖部作为传统的永久心脏起搏器植入位点,主要是因为电极容易放置及电极脱位率低。但是心尖部起搏属非生理性起搏,它使心室除极和机械收缩发生异常,从而导致长期的血流动力学紊乱(心室收缩和舒张异常)和组织结构的改变。随着近年主动固定的螺旋电极及螺旋电极操作手柄的问世,使右室流出道起搏成为可能。大量动物实验和临床研究提示右室流出道靠近房室结、希氏束部位,在此部位起搏心室激动和收缩顺序趋于正常,从而能明显的改善血流动力学指标。目前右室流出道起搏尚处于临床实验阶段,且关于右室流出道解剖位点的确定,适宜患者群的筛选标准、监测和评价指标的选择尚无统一的标准。其长期效果及能否改善患者预后等还有待更深入的研究。现就目前国内外关于右室流出道起搏的研究现状综述如下。

Current Situation of Right Ventricular Outflow Tract Pacing

The right ventricular apex (RVA) has been the routine site for placement of the ventricular pacing lead because of the ease of implantation and low rate of dislodgement. However, RVA pacing is not physiological because it produces aberrant LV depolarization and, in turn, mechanical LV asynchrony with resultant long-term unfavourable hemodynamic (abnormal systolic and diastolic function) and structural changes. As the active-fixation screw-in leads, and the screw-in leads manipulation handles come out, right ventricular outflow tract (RVOT) pacing has been possible. Many animal trials and clinical studies have indicated that RVOT is near the atrial ventricular node and His bundle, where correctly ordered ventricular activation and contraction can be achieved, and improve the hemodynamic index. RVOT pacing is still in the stage of clinical experiment, and lacks anatomical definition of RVOT, screening standardization of patients, and even the suitable monitoring and evaluating index. Further studies are needed to investigate the long-term effects and prognosis. This article outlines the current studies of RVOT pacing.