4种多普勒组织成像方式确定室性异位起搏点部位的比较性研究

The accuracy of different Doppler tissue imaging modes localizing ventricular premature site

目的分别探讨二维速度、加速度、M型及脉冲多普勒组织成像(DTI)模式对定位室性异位起搏点的价值及特征,为心内电生理标测提供重要信息。方法采用DTI不同模式对50例室性早搏(VP)、部分伴有室性心动过速(VT)的患者及10例行右室心尖部起搏患者进行研究。取胸骨旁左、右心室长轴、短轴观;心尖四腔、二腔观;右室流入道、流出道长轴观等各标准二维图像,分别采用二维、加速度DTI模式寻找与心电图所示的心室起搏或VP对应出现的最早激动亮点;采用M型及脉冲DTI速度模式测量心电图QRS波起点或刺激信号至局部心肌收缩带(波)起始的时间间期(△T),即电-机械兴奋间期,确定最短△T的部位,初步确定最早心室激动点即室性异位起搏点位置。部分病例以心内膜靶点准确定位标测或起搏点作对照。结果上述4种成像方式单独及联合运用后预测VP或心室起搏点的准确性分别为64%、77%、68%、73%和86%,各种方式间定位准确率无显著性差异,但联合运用与单独运用定位准确率间有显著性差异。结论二维、加速度DTI模式较直观;M型、脉冲DTI速度模式对时间、空间分辨力较强,对影像条件的依赖性较小。实际检查时联合运用可取长补短,从而有助于提高DTI预测VP起源或起搏点位置的准确性。该技术无创、安全、重复性良好,可与心内电生理标测技术相互补充,因此具有一定的临床应用价值。

Objective To investigate and compare the feasibility and accuracy of different Doppler Tissue Imaging （DTI） modes for predicting ventricular premature or pacing site. Methods The long-axis, and short-axis views of the left and right ventricles were observed. 50 VP patients with/without VT and 10 patients with permanent pacemakers were studied with DTI. 2D-DTV and DTA were used for localizing the earliest activation bright spot appearing on the endocardial side. M-DTV and PW-DTV were used for the evaluation of the shortest electromechanieal time interval （△T）. △T was measured from the onset of the QRS wave or pacing signal to the beginning of the ventricular systolic motion. The earliest contraction or VP site was defined as the site demonstrating the shortest AT and the earliest bright spot. Then the earliest contraction site was compared with the earliest activated site determined by the successful ablation site or pacing site in some patients. Results The shortest mean AT and the earliest bright spot were found at the right ventricular apical in patients with permanent pacemakers and at the VP . site in ventricular arrhythmia patients. The mean△T was observed during the sinus rhythm （76.9 ± 12.8 ms） and during the VP or abnormal pacing（42.3 ± 15.6 ms） by PW-DTV. The correlation of M-DTV and PW-DTV was good. The VP or abnormal pacing could be precisely localized in 64% patients by 2D-DTV, in 77% by 2D-DTA, in 68% by M-DTV, in 73% by PW-DTV and in 86% by a combination of the four modes. After the successful radiofrequency catheter ablation （RFCA） or during the sinus rhythm restoring, the bright spots and the time difference were found to disappear by DTI in all patients. Conclusion 2D-DTV and DTA were more directly viewed, while M-DTV and PWDTV were more accurate and special for time and space. DTI-determined earliest contraction sites coincided well with the sites of the VP determined by the EPS. The DTI, especially in combina- tion with the four modes, is helpful to localize the VP or pacing catheter and to evaluate the results after RFCA objectively, accurately and non-invasively.