左室和双心室起搏对犬心电及血流动力学的影响

目的探讨左室和双心室起搏对QRS波时限（QRSd）及血流动力学的影响。方法12只犬，开胸后于心外膜随机行右室心尖部、左室及双心室起搏，起搏频率为150次／min，起搏稳定15min后测定QRSd、平均肺动脉压（mPAP）、肺毛细血管楔压（PCWP）、心指数（CI）。结果与右室心尖部起搏相比：左室起搏时QRS波时限缩短不明显（P〉0．05），而双心室起搏时QRS波缩短明显（P〈0．05）；左室及双心室起搏时心指数显著增加，两种方式间差异无统计学意义。结论双心室起搏可同步改善心室的电活动及机械活动，而左室起搏不同，没有实现电同步但仍可获得近似于双心室起搏的血流动力学效果。

Effects of Cardiac Electrophysiology and Hemodynamics during the left ventricular and bi-ventricular Pacing in Dogs

Objective To study the effects of the left ventricular and bi-ventricular Pacing in dogs on QRS duration （QRSd） and hemodynamics. Methods After thoracotomy, the fight ventricular apical, the left ventricular and the bi-ventricular pacing were random performed on the epicardium among 12 dogs. The pacing frequency was at 150 beats per minute and the results were measured after 15 minutes when the pacing became stable, the measurement parameters included QRSd, mean pulmonary artery pressure （mPAP）, pulmonary capillary wedge pressure （PCWP） and cardiac index （CI）. Results Compared with the right ventricular apical pacing dogs, no significant QRS duration decreased in the left ventricular pacing dogs （ P 〉 0. 05）. In the bi-ventricular Pacing, there was an obvious QRS duration change （ P 〈 0. 05 ）. A significant increase appeared in CI in the left ventricular and bi-ventricular Pacing, but there was no obvious statistical difference between the two methods. Conclusion Bi-ventricular pacing could lead to a synchronous improvement in the cardiac electrophysiology and hemodynamics and it was different in the left ventricular pacing, which could not realize the cardiac electrophysiology synchronization and did not effect similar to hemodynamics as bi-ventricular Pacing.