本研究探讨了四氢巴马汀(L-THP)对跨室壁复极离散度(TDR)的影响和L-THP抗异丙肾上腺素诱发的室性心律失常(VA)作用及其机制。采用跨室壁单向动作电位记录技术研究L-THP对在体犬三层心肌动作电位时程(APD90、APD50)、有效不应期(ERP)和跨室壁复极离散度(TDR)的影响;局部心肌给予异丙肾上腺素(Iso)模拟突发交感神经张力增加;观察L-THP对程序电刺激(PES)所致的VA发生率和诱发VA所需的最低Iso浓度的影响。L-THP延长三层心肌的APD90 、APD50 和ERP,减少TDR(18.78±3.19ms vs 10.78±2.11ms,P<0.01);降低PES对VA的诱发率(21.61% vs 6.17%,χ2=14.8645,P<0.005);增加诱发VA所需要的最低Iso浓度(4.64×10^(-6)mg/ml vs 3.59×***/ ml,P<0.001)。L-THP降低TDR抑制折返的形成;抑制局部Iso引起的早期后除极和触发活动所致的VA;对APD、ERP和TDR的影响类似于胺碘酮,为一有开发应用前景的抗心律失常中药。四氢巴马汀降低TDR抑制折返的形成;抑制局部Iso引起的早期后除极和触发活动所致的VA;对APD、ERP和TDR的影响类似于胺碘酮,为一有开发应用前景的抗心律失常中药。
Studies have shown an association between left ventricular(LV) geometry and complex ventricular ectopic activity. Increased transmural dispersion of repolarization(TDR), which correlates to the interval from the peak ...
详细信息
Studies have shown an association between left ventricular(LV) geometry and complex ventricular ectopic activity. Increased transmural dispersion of repolarization(TDR), which correlates to the interval from the peak to the end of the T wave(Tpe) on the surface electrocardiogram, is linked to ventricular tachyarrhythmias. The relation between LV geometry and TDR is unknown. The mean Tpe interval, measured from leads V1 to V3 of the surface electrocardiogram,was assessed in 300 patients(50% men)who had normal LV systolic function and QRS duration and were categorized into 3 equal groups, which were matched by age and gender, according to echocardiographically determined LV geometry(normal structure, concentric remodeling, and LV hypertrophy). The Tpe interval was corrected for the QT interval using Tpe/QTc and was compared among the 3 groups. Compared with those who had normal LV structure, the Tpe interval was significantly prolonged in those who had LV hypertrophy and significantly shortened in those who had concentric remodeling(p=< 0.0001 for the 2 comparisons). Correcting for the QT interval using Tpe/QTc yielded similar results. Thus, TDR was increased in patients who had LV hypertrophy but decreased in concentric remodeling compared with those who had normal cardiac structure. Although LV hypertrophy represents a maladaptive geometric process that results in an unfavorable electrical substrate, concentric remodeling may represent a structural adaptation that has a more favorable electrical milieu.
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