双心室起搏心电图的额面心电轴分析

目的 分析行心脏再同步治疗（CRT）的患者在不同起搏模式下的心电图QRS波电轴的分布特点,以及与左心室导线位置、左心室逆重构的关系.比较12导联同步心电图机自动分析与手动测量的心电轴的差异.方法 入选2012年11月到2013年6月在上海复旦大学附属中山医院行CRT植入的41例患者,分别记录患者术后3个月在单纯左心室起搏,左心室提前60ms、40ms、20ms、0ms,右心室提前20ms、40ms,单纯右心室起搏的12导联同步心电图共326份,记录12导联同步心电图机自动分析得出的心电轴,同时手动测量I和aVF导联QRS波的净振幅,代入公式：心电轴=57.3＆#215;ATAN（aVF/I）,计算相应的心电轴.比较术前、术后6个月超声心动图结果左心室收缩未期内径（LVESD）],明确有无左心室逆重构发生.左心室逆重构定义为术后6个月LVESD减小≥15％.根据手术中左前斜位、后前位X线透视片明确左心室导线位置.结果 ①随着右心室起搏成分的减少,左心室成分的增加,QRS波额面电轴逐渐由左偏转为右偏（r,=0.412,P＜0.001）,不同的VV间期之间,QRS波额面电轴的分布不全相同（Pearson x2=68.7,P＜0.001）;②左心室导线植入部位与心电轴分布之间无明显的相关性（rs=0.08,P=0.149）;③在双心室同步起搏模式下,不同QRS波电轴分布范围,左心室逆重构的发生率差异无统计学意义（P=0.115）;④12导联同步心电图机自动分析与手动测量的QRS波额面电轴一致性程度一般（ICC=0.563,95％ CI：0.483～ 0.635,F=3.58,P＜0.001）.结论 VV间期的改变可使QRS波电轴产生迁移,起搏成分从右心室主导转移为左心室主导时,QRS波额面电轴出现顺时针偏移的现象.QRS波心电轴与左心室导线位置相关性差,仅根据心电轴难以判断左心室导线的位置.单一时间点双心室同步起搏QRS波电轴对于左心室逆重构无预测价值.12导联同步心电图机自动分析出的QRS波额面电?

Analysis of the QRS frontal axis of biventricular pacing electrocardiogram

Objective To analyze the distribution characteristics of QRS frontal axis of patients with cardiac resynchronization therapy（CRT） in the electrocardiograms（ECGs） under different pacing modes and its relationship with left ventricular（LV） lead position,and to assess the value of the QRS axis under simultaneously biventricular pacing mode to predict LV remodeling.Methods Fourty-one patients with complete left bundle branch block were enrolled consecutively at cardiac pacemaker clinic of Zhongshan Hospital between November 2012 and June 2013.Three hundreds and twenty-six ECGs were obtained at the 3-month follow-up after CRT under different settings：single LV output,LV pre-excitation with 60 ms,40 ms and 20 ms,respectively,simultaneous biventricular output,right ventricle pre-excitation with 20 ms and 40 ms,respectively,and single right ventricle output,from 41 CRT patients with complete left bundle branch block before CRT.QRS axis was measured automatically and manually for each ECG.LV remodeling was determined as ≥ 15% reduction in left ventricular end-systolic diemeter（LVESD） at 6 months.The positions of LV lead were ascertained by fluoroscopies in the postero-anterior and left anterior oblique view during the implantation.Results QRS frontal axis shifted from left to right in accordance with increasing LV pre-excitation interval（rs =0.412,P〈0.001）.QRS axis distributions under different interventricular intervals were significantly different（Pearson x2 =68.7,P〈0.001）.Distribution of QRS axis was poorly related to the LV lead position（rs =0.08,P=0.149）.No difference of the prevalence of LV remodeling was observed among different QRS axis under simultaneous biventricular pacing.The intra-class correlation coefficient of QRS axis measured automatically vs.manually was 0.563 （95% CI：0.483 ～ 0.635,F=3.58,P〈0.001）.Conclusion QRS axis changed when pacing with different interventricular intervals.In general,QRS axis shifted clockwise with gradually increased LV pre-excitation