家兔右心室异位激动对短时程心脏记忆的影响大于左心室

The impact of RV ectopic excitation on short-term cardiac memory is greater than that of LV in the rabbit

目的 研究家兔左、右心室异位激动对短时程心脏记忆的影响是否存在差异.方法 记录12只正常成年家兔Ⅱ导联体表心电图;将双极刺激电极分别置于左、右心室前壁游离壁心外膜下,以实现左、右心室分别起搏,模拟左、右心室异位激动;分析异位激动停止后20 min内窦性节律T波的形态和电轴偏转情况,并与起搏前的正常窦性心电图比较,以判断异位激动位置对短时程心脏记忆的影响.结果 左心室异位激动停止后,窦性T波形态基本正常,T波电轴偏转在正常范围内（14°～ 22°）.而右心室异位激动停止后,出现T波倒置,与同部位起搏前相比（P＜0.05）,这种T波倒置在所观察的20 min内持续存在.此外,右心室异位激动停止后,出现T波电轴明显右偏,与同部位起搏前相比（P＜0.05）,最大右偏角度达127.9°.结论 右心室异位激动后对短时程心脏记忆的影响较大,表现为显著T波倒置和T波电轴右偏,而左心室异位激动对短时程心脏记忆（包括T波形态和T波电轴）的影响不明显.

Objective To investigate the differential impact of right versus left ventricular ectopic excitation on the short-term cardiac memory. Methods Surface electrocardiogram （ECG） （Lead Ⅱ ） was recorded and bipolar electrode pacing was performed on the left ventricular （LV） and right ventricular （RV） anterior free walls at an open-chest condition in normal adult rabbits. Within 20 min after pacing, T wave morphology and T wave electrical axis were analyzed and compared with that of the same ventricles before pacing. Results After LV pacing, the T wave morphology was basically normal and the deflection of T axis was within normal range （14° -22°）. However, RV pacing resulted in significant T wave inversion and counter-clockwise deflection of T axis （ maximal deflection 127.9°） （P 〈 0. 05 compared with that of the same site before pacing, respectively）. Conclusions The influence of RV ectopic excitation on short-term cardiac memory is much greater than that of LV ectopic excitation： RV ectopic excitation induces serious T wave inversion and T axis counter-clockwise deflection, while LV ectopic excitation has no significant influence on T wave morphology and T axis.