应用自制复合电极同步记录兔左心室游离壁三层心肌的单相动作电位

应用自制复合电极同步记录家兔在体三层心肌的单相动作电位 (MAP) ,并与经典的心内膜电极、心外膜吸附电极和三层独立电极记录结果进行比较。结果显示 :①应用自制复合电极同步记录家兔在体的三层心肌MAP形态及时程与经典的记录结果相近 ;②在心动周期 (CL)为 30 0ms时 ,三层心肌的MAP复极达 90 %的时程 (MAPD90 )无显著差异 ,当CL为 80 0ms时 ,家兔心外膜心肌 (Epi)、中层心肌 (M)和心内膜心肌 (Endo)的MAPD90 分别为 2 15± 18,2 6 2± 16 ,2 16± 12ms,M与Epi及Endo相比 ,差异有显著性 (P <0 .0 5 ,n =8) ,跨室壁复极离散度为 34± 3ms。结论 :应用复合电极同步记录在体心肌跨室壁三层MAP是可行的 ,家兔心脏跨室壁心肌电生理在正常心率时无明显差异 ,而当心率减慢时则异质性增加。

Recording of Monophasic Action Potential Across the Left Ventricular Free Wall in Vivo With Composite Electrodes.

Monophasic action potentials(MAPs) of epicardium(Epi),midmyocardium(M),and endocardium(Endo) were recorded simultaneously with composite electrodes across the left ventricular myocardium in open-chest rabbits,compared with those recorded with classic endocardial electrode,epicardial suction electrode and isolated three layer electrodes.Results:①Shape characters and parameters of MAPs recorded with composite electrodes were similar to those of classic recording fashions.②At a cycle length(CL) of 300 ms,monophasic action potential duration(MAPD) recorded at three transmural sites were similar.When CL was increased to 800 ms,MAPDs were prolonged in all three layers.MAPD 90 in Epi,M and Endo were respectively 215±18,262±16,216±12 ms.MAPD 90 prolonged remarkably in M but only modestly in Epi and Endo(P<0.05,n=8).Transmural dispersion of repolarzation among three myocardial layers was 34±3 ms.The results suggest that composite electrodes is capable of recording MAPs across the left ventricular myocardium in vivo simulataneously.MAPD 90 were similar at CL of 300 ms in three layers but different at CL of 800 ms significantly.