心室偏心性除极时复极离散度指标的应用

The application of repolarization dispersion indices during eccentric ventricular depolarization.

目的 评价显性预激综合征时心室复极离散度指标 ( QTd和 JTd)的临床价值 ,以阐明偏心性心室除极是否导致心室复极离散度异常。方法 选择 4 6例成人显性预激综合征患者行射频消融术 ,观察射频消融前后的心室复极离散度指标 ( QTd和 JTd)的变化。结果 射频消融后最大 QRS时间较消融前缩短 ( 4 6± 2 8) ms,随着预激波消失和 QRS的“正常化”,消融后的 QTd[( 3 0± 13 ) ms]和 QTcd[( 3 7± 19) ms]较消融前的 QTd[( 5 1± 2 3 ) ms]和 QTcd[( 60± 2 7) ms]明显缩短( P值均 <0 .0 5 ) ,而消融后的 JTd[( 2 5± 10 ) ms]和 JTcd[( 2 8± 10 ) ms]与消融前的 JTd[( 2 7± 12 )ms]和 JTcd[( 3 2± 12 ) ms]相比无明显变化 ( P值均 >0 .0 5 )。消融前的预激 QRS波群导致消融前后 QTd和 QTcd的差别。由于消融前后 JTd和 JTcd并无差异 ,表明心室偏心除极不导致复极离散度异常。结论 在显性预激存在时 ,测定心室复极离散度使用 JTd和 JTcd优于 QTd和 QTcd;同时 ,预激时的心室偏心除极不导致复极离散度异常 ,即心室偏心除极不是导致复极离散度异常的机制。

abstract Objective To evaluate the clinical value of indices (QTd & JTd)of ventricular repolarization dispersion, and find out if eccentric ventricular depolarization leads to abnormal ventricular repolarization dispersion.Methods The changes of repolarization dispersion indices before and after successful radiofrequency ablation in 46 adult patients with overt preexcitation were observed.Results The maximum QRS interval shortened (46±28)ms after ablation.With the disappearance of delta wave and the normalization of QRS interval,the QTd(30±13)ms and QTcd(37±19)ms after ablation become shorter than those before ablation (QTd 51±23ms; QTcd 60±27 ms)(P<0.05),whereas the JTd(25±10)ms and JTcd(28±10)ms after ablation remained unchanged compared with the JTd(27±12)ms and JTcd(32±12)ms before ablation(P>0.05).The preexcited QRS waveform before ablation caused the changes of QTd and QTcd.Because JTd and JTcd kept unchanged, the eccentric ventricular depolarization did not lead to abnormal repolarization dispersion. Conclusion When preexcitation exists, JTd and JTcd rather than QTd and QTcd should be used to know ventricular depolarization dispersion, and the eccentric ventricular depolarization does not lead to abnormal repolarization despersion.