24小时快速起搏右心房对兔心房单向动作电位的影响

目的应用心内电生理技术研究心房快速起搏(RAP)对兔心房单向动作电位(MAP)的影响。方法成年新西兰兔20只随机分为二组:假手术组、模型组各10只。经颈内静脉将电极置入右心房。以600次/分行RAP,同时分析在0、4、8、12和24h的单向动作电位时程(MAPD)。结果假手术组在实验的时间段内右房游离壁MAP复极90%时程(MAPD90)无明显差别。RAP8h,起搏组右房游离壁MAPD90较P0有明显缩短,从起搏前(112.50±9.57)ms至起搏8h分别缩短到(51.25±4.79)ms,分别缩短了61.25ms。结论房颤(AF)时心房MAPD90缩短。MAP技术可安全地用于研究AF时的电重构(ER),能提供准确的电生理改变的信息。

Effect of 24 Hours Rapid Atrial Pacing on Atrial Monophasic Action Potential in Rabbits

Objective To study the effect of 24 hours rapid atrial pacing on atrial monophasic action potential （MAP） and atrial electrical remodeling （ ER） in rabbits. Methods Twenty New Zealand white rabbits of either sex （weight 2. 5 to 3. 0 kg,n = 20） were randomly divided into 2 groups： sham operated group （n = 10） and model group （n = 10）. All animals were euthanized with pentobarbital （30 mg/kg followed by 5 mg/kg/h,i. v. ）. Atrial effective refraction period （AERP） was measured by programmed electrical stimulation before pacing and from 0 to 24 hours after the onset of the pacing. Results In the sham operated group,monophasic action potential duration 90% （MAPD90 ） was not changed at all experimental intervals. In the model group,MAPD90 was shortened in P8 through the pacing process compared with those before pacing （P〈0. 05）. Conclusion The MAPD90 is shortened by rapid atrial pacing in rabbits. MAP technique is safe for studying electrical remodeling of atrial fabrillation（AF） and may provide accurate information of electrophysiological changes.