微伏级T波电交替对晕厥患者发生恶性室性心律失常的预测价值

Prognostic value of microvolt level T wave alternans for malignant ventricular arrhythmia in syncope patients

目的探讨Holter时域法微伏级T波电交替(MTWA)检测对晕厥患者发生恶性室性心律失常(MVA)及心脏性猝死(SCD)的预测价值。方法选取199例晕厥患者行MTWA检测,其中102例诊断为迷走反射性晕厥并排除有器质性心脏病,设为迷走晕厥组;97例既往有MVA发作史或确诊为心源性晕厥,设为心源性晕厥组;105例健康体检者设为对照组。晕厥两组均检测MTWA、左室射血分数(LVEF)、心率变异性(HRV)及Q-T离散度(Q-Tc)及室性心动过速(VT)等指标,随访并比较不同组间各指标的差异及相关性。结果 MTWA95%正常值参考范围<36 V;心源性晕厥组与对照组、迷走晕厥组的MTWA均值、阳性率差异有统计学意义(均<0.05),而对照组与迷走晕厥组差异无统计学意义(均>0.05);随访发现迷走晕厥组与心源性晕厥组各指标差异均有统计学意义(均<0.05);MTWA阴性组与阳性组MTWA、LEVF、Q-Tc及MVA差异有统计学意义,其他指标差异均无统计学意义;且MTWA的敏感性及预测价值均比其他指标高。结论国人时域法MTWA正常参考值为<36 V,MTWA对迷走反射性晕厥患者预测MVA和SCD无价值;对心源性晕厥预测MVA和SCD具有独立预测价值,联合LVEF可进一步提高预测价值。

Objective To explore the predictive value of Holter time-domain microvolt level T-wave alternans（MTWA） for malignant ventricular arrhythmia（MVA） and sudden cardiac death（SCD） in syncope patients.Results One hundred and ninety-nine patients with symptoms of syncope were enrolled as syncope group.Among them,102 cases were excluded of structural heart disease and diagnosed vasovagal syncope;the other 97 cases of previous MVA or had cardiac syncope history were diagnosed cardiac syncope.One hundred and five healthy subjects were enrolled as control group.MTWA values,LVEF,HRV,Q-Tc and VT were detected and analyzed during the followup period.Results The 95% normal reference value of MTWA was defined as 36？ V.Mean value and positive rate of MTWA in cardiac syncope group were significantly higher than those of vasovagal syncope group and control group（ 0.05）,but they did not reach significant difference between syncope group and control group（ 0.05）.All the parameters detected during the follow-up had significant difference between vasovagal syncope group and cardiac syncope group（ 0.05）.MTWA,LEVF,Q-Tc and MVA had significant difference between MTWA positive group and MTWA negative group（ 0.05）,while the other parameters had no significant difference between the two groups.The sensitivity and predictive value of MTWA were higher than other parameters.Conclusions The normal MTWA reference value of Chinese time-domain method was less than 36？ V.MTWA has no predictive value on MVA and SCD of vasovagal syncope,while has independent predictive value on MVA and SCD of cardiac syncope.The combination of MTWA and LVEF can further improve the predictive value.