跨室壁复极离散变化及其对心电图T波影响的在体实验研究

为探讨在体情况下心肌跨室壁复极离散变化及其对心电图T波影响的可能机制。运用单相动作电位 (MAP)记录技术 ,同步记录 2 1只开胸兔的左室心肌心外膜层 (Epi) ,中层 (Mid) ,内膜层 (Endo)的MAP ,分别予以减慢心率、静脉注射索他洛尔 (dl sotalol)、海葵毒素 (ATX Ⅱ )后 ,观察跨室壁复极离散的变化以及心电图T波的相应改变。结果 :①慢频率导致Mid层细胞MAP复极时间 (RT)显著延长 (从 2 0 2± 19ms到 370± 34ms,P <0 .0 5 ) ,跨壁复极离散度 (TDR)增大 (从 11± 4ms到 40± 2 1ms,P <0 .0 5 ) ,QT间期延长 (从 2 0 5± 2 1ms到 371± 30ms,P <0 .0 5 ) ,T波增宽。②dl sotalol导致Mid层细胞MAP的RT显著的延长 (从 2 0 2± 19ms到 395± 34ms,P <0 .0 5 ) ,TDR增大 (从 10± 3ms到 75± 2 5ms ,P <0 .0 5 ) ,QT间期延长 (从 2 0 8± 16ms到 397± 33ms,P <0 .0 5 ) ,三层心肌MAP的 3相复极不同程度的延长 ,使复极电位梯度变化 ,产生增宽、低幅有切迹的T波。③ATX Ⅱ导致Mid层细胞MAP的RT显著的延长 (从370± 34ms到 473± 35ms,P <0 .0 5 ) ,TDR增大 (从 40± 2 1ms到 6 2± 19ms,P <0 .0 5 ) ,QT间期延长 (从 372± 33ms到 479± 33ms,P <0 .0 5 ) ,三层心肌MAP的 2相平台期不同程度延长 ,使复极电位梯

The Research of The Variation in Transmural Dispersion of Repolarization and Its Effect on T-Wave in ECG in Vivo.

To investigate the variation in transmural dispersion of repolarization(TdR) and its effect on T-wave in ECG in vivo.With the monophasic action potential(MAP) recording technique,epicardium(Epi),midmyocardium(Mid) and endocardium(Endo) were recorded by specially designed plung-needle electrodes at the left ventricular myocardium in 21 openchest rabbits.After intravenous injection of dl-sotalol,ATX-Ⅱ and slowing-rates separately,Variation of TdR among three myocardial layers as well as T-wave in ECG were investigated.Results:①slowing-rates caused a preferential prolongation of the Mid-cell repolarization time(RT) of MAP (from 202±19 ms to 370±34 ms,P<0.05),increased TdR(from 11±4 ms to 40±21 ms,P<0.05) and QT interval (from 205±121 ms to 371±30 ms,P<0.05),broad ened T waves.②dl-sotalol caused a preferential prolongation of the Mid-cell RT (from 203±18 ms to 395±34 ms,P<0.05),giving rise to broad and sometimes low amplitiude bifurcated T waves and an increased TDR (from 10±3 ms to 75±25 ms,P<0.05).QT interval increased from 208±16 ms to 397±33 ms,P<0.05.③ATX-Ⅱ caused preferential prolongation of the Mid-cell RT(from 370±34 ms to 473±35 ms,P<0.05)and caused a marked delay in the onset of the T waves and a sharp rise in TDR(from 40±21 ms to 62±19 ms,P<0.05).QT interval increased from 372±33 ms to 479±33 ms,P<0.05.Conclusions:the variation in TdR of ventricular myocardium has an important effect on the T wave in ECG in vivo of the rabbit.