双道超声心动图对正常人等容舒张期时相划分的研究

目的：通过观察分析正常人左室等容舒张期内的结构和血流变化，明确其各时相及相应的时间周期，为应用心脏同步化治疗提供依据。方法：选取60例健康体检者，通过常规二维左心室血流脉冲多普勒（PW）和组织多普勒（TDI）检查，录取左心室PW、TDI和双声道超声心动图（DCE）图像，将所有受检者等容舒张时间（WRT）分为等容舒张早期（IVRTe）和等容舒张后期（IVRTl）并测量各时相时间间期，测量指标包括：①等容舒张期时间间期（IVRT）；②等容舒张早期时间间期（IVRTe）；③等容舒张后期时间间期（IVRTl）；④IVRTl／IVRT；并计算心率校正后数值：⑤cfVRT；⑥cIVRTe；⑦cIVRTl；⑧cIVRTl／clVRT；⑨测量DCE上二尖瓣血流变化与组织运动时间差（TE-6）。结果：观察分析入选的45例图像，PW曲线上均观测到IVRT内i波存在，i波约占IVRT的1／2，平均值为（49．17±5．37）ms，以i波下降支转折点为t点，可将IVRT划分为IVRTe和IVRTl。84％TDI曲线上观测到IVRT内j波存在，j波约占IVRT的1／2，平均值为（43．13±4．83）ms，以j波形成点为t点，可将IVRT划分为IVRTe和IVRTl。PW、TDI、DCE三组测量指标进行比较，仅有常规PW与TDI所测量的IVRT、IVRTe、IVRTl数值有统计学差异（P〈0．05）；常规PW和TDI测量数值分别与DCE所测数值比较，均无统计学差异。校正心率后，三组之间两两比较，其所测数值差异均无统计学意义。三组所测IVRTl／IVRT、cIVRTl／cIVRT差异均无统计学意义，所测数值的平均值为（0．50±0．12）ms。经重复性检验证实．DCE测量IVRT各时相时间间期的测量误差较小，有较好的一致性。结论：研究发现IVRT可进一步划分为两个时相即IVRTe和IVRTl，IVRTe内有i波存在，IVRTl内有i波存在，划分点t点大致为IVRT中点。

Analysis of the phase of left ventricular isovolumic relaxation time in healthy people using dual-channel echocardiography

Objective： To exacted analysis each time interval in isovolumic relaxation time （IVRT） of normal subjects through observing the changes of cardiac structure and hemodynmnics during the IVRT. Then to provide the evidence of cardiac resynchronization therapy. Methods： Quantitative analysis was performed for 60 subjects. The dual-channel echocardiography（DCE） , pulse wave doppler（PW） and tissue wave dapper（TDI） examination of all the subjects were recorded, and IVRT was divided into two intervals, isovolumie relaxation time of early intervals （IVRTe） and isovolumic relaxation time of late interval （IVRT1）.Then measured the time of each interval. Indicators were used including： （1）IVRT; （2）IVRTe; （3）IVRT1; （4）WRTl/IVRT; calculating the data after heart rate corrected; （5）cIVRT; （6）cIVRTe; （7）cIVRTl; （8）cIVRTl/cIVRT; （9）measuring the time difference in mitral blood and tissue （TE-6） of DCE group. Results： The i-wave within IVRT in PW images was found in 45 subjects, and the i-wave was about 1/2 of IVRT（49.17 ± 5.37）ms. WRT was divided into IVRTe and IVRTl by a turning point at descending branch of i-wave as t-point. The j-wave was observed in 84% TDI images, and the j-wave was about 1/2 of IVRT （43.13 ± 4.83）ms. 1VRT was divided into IVRTe and IVRTl by a turning point of the onset of j-wave as t-point. A significant difference was found between PW and TDI with measurement of IVRT, IVRTe, 1VRTI（ P 〈 0.05）. There were no significant differences between the common group and DCE group （ P 〉 0.05）. After heart rate corrected, the data showed no significant difference using pairwise comparisons among the three groups （ P 〉 0.05）. The mean and standard deviation of IVRT1/IVRT, clVRTI/clVRT were（0.50 ± 0.12）ms. There were little difference of time intervals and good consistenc using DCE measured IVRT with multiple tests confirmed. Conclusion： The study found that IVRT might be divided into WRTe and IVRTl phases. There were i-wave in IVRTe and j-wave in IVRTl. The t-point was nearly midpoint inisovolumic relaxation time.