心室不同部位起搏对正常犬和扩张型心肌病心力衰竭犬模型在体心肌跨室壁复极离散的影响  

Influence of pacing site on myocardial transmural dispersion of repolarization in intact normal and dilated cardiomyopathy dogs

作　　者：白融[1] 卜军[1] 刘念[1] 吕加高[1] 周强[1] 阮燕菲[1] 牛惠燕[1] 王琳[1] 

机构地区：[1]华中科技大学同济医学院附属同济医院心内科,武汉430030

出　　处：《生理学报》2003年第6期722-730,共9页Acta Physiologica Sinica

摘　　要：实验以正常犬和扩张型心肌病心力衰竭犬(dilated cardiomyopathy congestive heart failure,DCM-CHF)模型为对象、以心肌跨室壁复极离散的相关参数为指标,研究左心室心外膜起搏、双心室起搏(模拟临床上心室再同步治疗的方法)后的心肌电生理特性变化。实验以快速右心室起搏的方法制备DCM-CHF犬模型;正常犬和DCM-CHF犬均经射频消融希氏束制备三度房室传导阻滞模型;采用同步记录犬体表心电图和内膜下、中层、外膜下三层心肌单相动作电位(monophasic action potentials,MAP)的方法,测定不同部位起搏时的QT间期、Tpeak-Tend(Tp-Te)间期和三层心肌的单相动作电位时程(MAP duration,MAPD)、跨室壁复极离散度(transmural dispersion of repolaization,TDR)。结果显示:在正常犬,左室心外膜与双心室起搏后三层心肌的MAPD均延长,同时TDR增大(左室心外膜起搏47.16 ms、双心室起搏37.54 ms、右室心内膜起搏26.75 ms,P<0.001),体表心电图Tp-Te间期的变化与之平行;在DCM-CHF犬较正常犬已表现出中层心肌MAPD延长(276.30 ms vs 257.35 ms,P<0.0001)和TDR(33.8 ms vs 27.58 ms,P=0.002)增大的基础上,左室心外膜参与起搏后仍进一步使三层心肌的MAPD延长和TDR增大。研究结果提示,左室心外膜起搏和双心室起搏后使内膜下。In order to verify the hypothesis that left ventricular epicardial (LV-Epi) pacing and biventricu-lar (BiV) pacing unavoidably influence the myocardial electrophysiological characters and may result in high risk of malignant ventricular arrhythmia, we calculated, in both normal mongrel dogs and dog models with rapid-right-ventricular-pacing induced dilated cardiomyopathy congestive heart failure ( DCM-CHF) , the monophasic action potential duration (MAPD) and the transmural dispersion of repolarization (TDR) in int-racardiac electrogram together with the QT interval and Tpeak-Tend(Tp-Te) interval in surface electrocardiogram (ECG) during LV-Epi and BiV pacing, compared with those during right ventricular endocardial (RV-Endo) pacing. To prepare the DCM-CHF dog model, rapid right ventricular pacing (250 bpm) was performed for 23. 6 ±2.57 days to the dog. All the normal and DCM-CHF dogs were given radio frequency catheter ablation ( RFC A) to His bundle with the guide of X-ray fluoroscopy. After the RFC A procedures, the animals were under the situation of complete atrioventricular block so that the canine heart rates could be voluntarily controlled in the following experiments. After a thoracotomy, ECG and monophasic action potentials (MAP) of subendocardial, subepicardial and mid-layer myocardium were recorded synchronously in 8 normal and 5 DCM-CHF dogs during pacing from endocardium of RV apex (RV-Endo) , epicardium of LV anterior wall (LV-Epi) and simultaneously both of the above ( biventricular, BiV) , the later was similar to the ventricular resynchronization therapy to congestive heart failure patients in clinic. The Tp-Te meant the interval from the peak to the end of T wave, which was a representative index of TDR in surface ECG. The TDR was defined as the difference between the longest and the shortest MAPD of subendocardial, subepicardial and mid-layer myocardium. Our results showed that in normal dogs, pacing participating of LV ( LV-Epi, BiV) prolonged MAPD of all the three layers of the myocardium (

关 键 词：电生理学 充血性心力衰竭 起搏 动作电位 跨室壁复极离散 

分 类 号：R541.6[医药卫生—心血管疾病]