犬快速心房起搏心房颤动模型全心房心外膜标测以及静脉胺碘酮对其心电的影响

Atrial Mapping of Sustained Atrial Fibrillation and Effects of Amiodarone on Electrophysiological Charactaristics in A Rapid Atrial Pacing Canine Model

探讨快速心房起搏心房颤动(简称房颤)模型房颤发作时肺静脉、左右心房各部位激动频率的差异以及胺碘酮对其电生理特性的影响。选健康雄性杂种犬10只,以400次/分的固定频率进行右心耳起搏,建立快速心房起搏房颤模型。10周后终止起搏,行64道全心房心外膜标测。标测部位分别为左右心房游离壁、左右心房顶部、左上肺静脉、左下肺静脉、右上肺静脉和右下肺静脉。记录以上部位的心外膜电图,测量各标测部位的平均房颤波周长(AFCL),并对不同部位心外膜标测电图进行频谱分析。静脉注射胺碘酮300mg,分析胺碘酮治疗前后各部位有效不应期(ERP)和AFCL的变化。结果:8只犬完成整个实验。在所有8只犬中,最短AFCL/ERP位于Marshall韧带的有2只,位于左下肺静脉的有6只;AFCL/ERP在心房的分布呈明显的梯度分布,自短至长依次为:肺静脉或Marshall韧带、左房游离壁和左侧Bachmann束、右侧Bachmann束和右房游离壁;频谱分析结果与AFCL分析结果一致;胺碘酮虽然可延长肺静脉和心房各部位ERP和AFCL,但是不能终止房颤的发作。结论:局灶机制可能是快速心房起搏房颤模型的发生和维持机制。

To investigate thesources of rapid activation, active rate gradient between left atrium（ LA）, right atrium（RA） and effects of amiodarone on electrophysiological characteristics in a canine model, rapid atrial pacing with a rate of 400 beats per minites was performed in 10 mongrel dogs. After 10 weeks rapid pacing. Computerized mapping of atrium for 64 electrodes was performed. The mapping areas included LA free wall, RA free wall, top of LA and RA, and 4 pulmonary veins（PVs）. Atrial fibrillation cycle length （AFCL） from different regions were measured and Fast Fourier transforms were performed. Effective refractory period（ERP） and AFCL were measured before and after venous amiodarone injection . Results： The experiment was successfully performed in 8 dogs. During sustained AF, the shortest AFCL/ERP was ligament of Marshall （LOM） in 2 dogs and the left inferior PV in 6 dogs. There was also an AFCL/ERP gradient ： AFCL/ERP in the LA free wall and the left side Bachmann＇s bundle（LBB） was significantly shorter than that in the right side Bachmann＇s （RBB） and the RA free wall（ P 〈 0.05 ）. Spectrum analysis also shown left-to-right frequency gradient and the highest frequency was always seen in the LOM or PV. Although amiodarone could prolong atrium and pulmonary veins ERP and AFCL, atrial fibrillation could not be terminated. Conclusions ： Focus mechanism may be the sources of rapid activation in this sustained AF model.