摘要：
Objective To explore the mechanisms of ligament of Marshall (LOM) initiat and sustain atrial fibrillation (AF).Methods The electrophysiologic properties of canine LOM were investigated using multipolar catheter mapping(normal canines,n =4,group A;AF canines,n =5,group B).The programmed stimulation were performed in the LOM,PV-left atrium(LA)junction and LA,respectively.Activations maps of LOM were analyzed from episodes of spontaneous onset of AF and initiation of induced AF by a single extrastimulus.The effectives refractory period of each part was compared and statistically analyzed among three parts in each group and between the two groups.LOM were cutted with surgical incision technology.The inducing rate of AF and the mapping rate of double potential and fragmented electrocardiogram were compared and statistically analyzed pro and post isolation of LOM.Results The incidence of abnormal potential of LOM in the two groups was significantly different(P ＜0.01),re-entry cycle(group A 25％ vs.B group 80％),tachycardia(group A 25％ vs.B 100％),double potential(group A 25％ vs.group B 80％),fragmentation potential(group A 25％ vs.group 80％).There was a significant difference in the rate of LOM tachycardia induction before and after LOM intervention in group B (P ＜ 0.05,before 100％ vs.after 20％).Conclusion There are two possible mechanisms of LOM involved in the occurrence and maintenance of AF:one is that LOM induces AF through spontaneous excitation,the other is that LOM participates in the reentry of left atrium and pulmonary vein in the form of bypass to induce and maintain AF.%目的 探讨Marshall韧带(LOM)在心房颤动(房颤)中的作用机制.方法 对9只健康杂种雄犬行电生理学检查,其中健康杂种犬4只(A组),持续性房颤犬5只(B组).测定两组犬LOM电生理学及组织学特征,标测是否存在折返环特征,对比并作统计学处理.外科干预LOM,对比干预前、后两组犬的电生理学特性变化.结果 两组LOM异常电位发生比例有显著性差异(P＜0.01):折返环发生比例(A组25％,B组80％),心动过速(A组25％,B组100％),双电位(A组25％,B组80％),碎裂电位(A组25％,B组80％).干预前、后B组LOM心动过速诱发比例差异有统计学意义(P ＜0.05,干预前100％,干预后20％).结论 LOM参与房颤发生和维持的两种可能机制:一是LOM通过自发激动诱发房颤;二是以旁路形式参与左心房与肺静脉之间的折返,诱发和维持房颤.
