【作者】 侯煜；

【导师】 方丕华；

【作者基本信息】 北京协和医学院 ， 内科学， 2012， 博士

【摘要】 目的：本研究旨在评价多项无创心电学指标：T波电交替(TWA)、窦性心率震荡(HRT)、心率变异性(HRV)、非持续性室速(NSVT)、室性早搏(VPBs)、心室晚电位(VLP)、QT司期(QTc),在心肌梗死早期作为心脏性猝死(SCD)预测因子的预测价值,并探索理想的联合方案,识别心肌梗死后猝死高危人群。方法：连续入选我院CCU病房289例急性心肌梗死患者,心肌梗死急性期(2周内)给予常规12导联体表心电图、平均信号心电图及动态心电图检查。体表心电图测定QRS波宽度和QTc间期：QRS波增宽定义为QRS波宽度>110ms,QTc延长定义为QTc间期>450ms(男性)/460ms(女性)；心室晚电位(VLP)是应用正交Frank导联系统滤波后矢量值的时域测量法测定(GE公司MAC5000),阳性标准为：RMS40<20μV+f-QRS)>114ms和/或LAS40>38ms;动态心电图测定：TWA、HRT、HRV;计算机软件应用改良的修正平均心搏(modified moving average MMA)算法来识别动态心电图记录期内存在的TWA,采用TWA≥47μV为界点；HRT异常定义为TO异常或/TS异常；HRV异常定义为SDNN<70ms;同时动态心电图可以记录室性早搏(30次/小时为频发)和非持续性室速(连续3个以上室性早搏,且心率大于100次/分)；二维超声心动图测LVEF值,心功能下降定义为LVEF随访一级终点为心脏性猝死或致死性室性心律失常,全因死亡和非心律失常性心脏性死亡为二级终点。结果：平均随访11±3月,期间有15例(5%)患者发生SCD。与幸存组患者相比,SCD组患者LVEF明显低[35%(28%-52%) vs50%(33%-60%), P<0.0001], QRS波宽度明显较长[115(88-152)ms vs105(91-136)ms, P=0.022],而QTc间期无显著差异[458(416-513)ms vs450(394-493)ms, P=0.183]; COX多因素分析：显示TWA、VLP、HRT (TS)及NSVT对心脏性猝死具有预测价值,风险比分别为：15.07(95%可信区间,2.88～78.68；p=0.001)；6.49(95%可信区间,2.13～19.77；p=0.0031)、4.21(95%可信区间,1.18-14.99；p=0.026)及16.78(95%可信区间,3.68～44.41；p<0.0001)。且24小时内发生T波电交替(≥47μ V)的频次超过5次的患者发生SCD的风险更高,其风险比为18.24(95%可信区间,4.20-83.68；p=0.0004)。联合NSVT或TS可提高VLP预测能力,风险比由6.49分别提高到16.07及14.21。结论：心肌梗死急性期(2周内)出现NSVT或TWA≥47μV且发生频次≥5次/24h的患者发生SCD的风险较大；阳性VLP同时伴有异常TS或NSVT能够识别发生心脏性猝死的高危患者。更多还原

【Abstract】 OBJECTIVES:The purpose of this study was to assess a number of non-invasive cardiac electrical indicators (TWA, HRV, HRT, NSVT, VPBs, VLP, QTc) to identify AMI patients at increased risk for SCD, and designed to evaluate the value of all indicators as predictors of SCD in the early post MI period and to find the optimal way to combine and use these noninvasive techniques in clinical practice.METHODS:289consecutive post-MI patients were enrolled in the study. Body electrocardiograph, Ambulatory ECG-based measures and signal-averaged electrocardiography were performed within2weeks after AMI. The duration of QRS wave and the QTc interval were measured by body electrocardiograph. The wide QRS wave was defined as its duration longer than110ms. The extended QTc interval was defined as its value longer than450ms for male or460ms for female. The analysis of VLP is based on the quantitative time-domain measurements of the filtered vector magnitude of the orthogonal Frank X, Y, and Z leads. VLP were considered to be present when the three criteria (RMS40≤20mV+f-QRS≥114ms, and/or LAS40≥38ms) were met. We analyzed hazard ratios using the previously determined47μV TWA cutpoint. Impaired HRT was defined by abnormalities in either HRT onset (TO value of>0) or slope (TS value of<2.5ms/per normal-to-normal interval).The standard deviation of all normal-to-normal R-R intervals (SDNN) was chosen as a parameter of HRV in this study, and a value of<70ms was pre-defined as abnormal. VPBs (30or more VPBs per hour) and NSVT (≥3consecutive ventricular premature beats at a rate of100beats/min) were also recorded by an ambulatory ECG. The left ventricular dysfunction was defined as LVEF lower than35%. The primary outcome was prospectively defined as sudden cardiac death or life-threatening ventricular arrhythmic events. All cause mortality and cardiac deaths categorized as nonarrhythmic were secondary outcomes.RESULTS:The duration of follow-up was11±3months.15(5%) patients died suddenly. Compared to the patients in survived group, the patient with SCD had lower LVEF[35%(28%-52%) vs50%(33%-60%), P<0.0001], longer duration of QRS wave[115(88,152)ms vs105(91,136)ms, P=0.0222] and longer QTc interval [458(416,513)ms vs450(394,493)ms, P=0.1836]. Multivariate Cox Regression Analyses showed that an ambulatory ECG-based TWA, VLP, TS and present NSVT were predictors of the primary outcome. A hazard ratio for TWA was15.07(95%CI2.88to78.68; p=0.001), for VLP was6.49(95%CI2.13to19.77; p=0.0031), for TS was4.21(95%CI1.18to14.99; p=0.026) and for NSVT was16.78(95%CI3.68to44.41; p<0.0001). Moreover, patients with≥5TWA episodes≥47μV were at higher risk for SCD [Hazard ratio=18.24(95%CI,4.20to83.68), p=0.0004]. United TWA and TS can improve VLP predictive capability, the hazard ratio (HR), respectively, from6.49to16.07and14.21.CONCLUSIONS:TWA (≥47μV) monitored within2weeks after AMI predicted heightened risk of SCD. Prediction is improved when the frequency of TWA episodes≥47μV is analyzed. Patients were found to be at the higher risk if they met the both positive VLP and TS or TWA.更多还原