CHRONIC RAPID ATRIAL-PACING - STRUCTURAL, FUNCTIONAL, AND ELECTROPHYSIOLOGICAL CHARACTERISTICS OF A NEW MODEL OF SUSTAINED ATRIAL-FIBRILLATION
CHRONIC RAPID ATRIAL-PACING - STRUCTURAL, FUNCTIONAL, AND ELECTROPHYSIOLOGICAL CHARACTERISTICS OF A NEW MODEL OF SUSTAINED ATRIAL-FIBRILLATION
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DOI：
10.1161/01.cir.91.5.1588
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发表时间：
1995-03-01
期刊：
影响因子：
37.8
通讯作者：
GUIRAUDON, CM
中科院分区：
文献类型：
--
作者：
MORILLO, CA;KLEIN, GJ;GUIRAUDON, CM
背景：尽管心房颤动（AF）的临床重要性，慢性非瓣膜性房颤模型的开发一直很困难。持续性房颤的动物模型主要是在短期内建立的。最近，慢性心室肌病和纤维性颤动的模型在连续几周的心室快速起搏后被开发出来。我们假设慢性快速心房起搏会导致心房肌病，并建立了一个可重复的持续心房颤动模型。方法和结果22只麻醉的杂种狗在右心房附耳插入经静脉导联，连续6周以每分钟400次的速度起搏。对11只犬进行二维超声心动图检查，评价快速心房起搏对心房大小的影响。心房易感性被定义为在程序性电刺激期间诱发持续重复心房反应的能力，并通过外刺激和突发起搏技术进行评估。在右心房两个心内膜部位测量有效不应期（ERP）。持续AF定义为AF大于或等于15分钟。在患有持续性房颤的动物中，10个四极心外膜电极通过手术连接到左右心房。在20秒窗内测量局部心房纤颤周期长度（AFCL），并测量每个部位的平均AFCL。双房明显增大；连续快速心房起搏6周后，左心房在基线时为7.8+/-1 cm(2)，起搏后为11.3+/-1 cm(2)；右心房在基线时为4.3+/-0.7 cm(2)，起搏后为7.2+/-1.3 cm(2)。心房面积至少增加40%是诱发持续性房颤的必要条件，且与房颤的诱发性密切相关（r= 0.87）。心房组织的电子显微镜显示结构变化，其特征是线粒体大小和数量的增加以及肌浆网的破坏。连续快速心房起搏6周后，18只狗（82%）诱发持续性房颤，2只狗（9%）诱发非持续性房颤。4只犬（18%）发生房颤。在基线周期长度为400和300毫秒时测量的右心房ERP，起搏后显著缩短，分别从150+/-8毫秒缩短至127+/-10毫秒，从147+/-11毫秒缩短至123+/-12毫秒
Background Despite the clinical importance of atrial fibrillation (AF), the development of chronic nonvalvular AF models has been difficult. Animal models of sustained AF have been developed primarily in the short-term setting. Recently, models of chronic ventricular myopathy and fibrillation have been developed after several weeks of continuous rapid ventricular pacing. We hypothesized that chronic rapid atrial pacing would lead to atrial myopathy, yielding a reproducible model of sustained AF.Methods and Results Twenty-two halothane-anesthetized mongrel dogs underwent insertion of a transvenous lead at the right atrial appendage that was continuously paced at 400 beats per minute for 6 weeks. Two-dimensional echocardiography was performed in 11 dogs to assess the effects of rapid atrial pacing on atrial size. Atrial vulnerability was defined as the ability to induce sustained repetitive atrial responses during programmed electrical stimulation and was assessed by extrastimulus and burst-pacing techniques. Effective refractory period (ERP) was measured at two endocardial sites in the right atrium. Sustained AF was defined as AF greater than or equal to 15 minutes. In animals with sustained AF, 10 quadripolar epicardial electrodes were surgically attached to the right and left atria. The local atrial fibrillatory cycle length (AFCL) was measured in a 20-second window, and the mean AFCL was measured at each site. Marked biatrial enlargement was documented; after 6 weeks of continuous rapid atrial pacing, the left atrium was 7.8+/-1 cm(2) at baseline versus 11.3+/-1 cm(2) after pacing, and the right atrium was 4.3+/-0.7 cm(2) at baseline versus 7.2+/-1.3 cm(2) after pacing. An increase in atrial area of at least 40% was necessary to induce sustained AF and was strongly correlated with the inducibility of AF (r=.87). Electron microscopy of atrial tissue demonstrated structural changes that were characterized by an increase in mitochondrial size and number and by disruption of the sarcoplasmic reticulum. After 6 weeks of continuous rapid atrial pacing, sustained AF was induced in 18 dogs (82%) and nonsustained AF was induced in 2 dogs (9%). AF occurred spontaneously in 4 dogs (18%). Right atrial ERP, measured at cycle lengths of 400 and 300 milliseconds at baseline, was significantly shortened after pacing, from 150+/-8 to 127+/-10 milliseconds and from 147+/-11 to 123+/-12 milliseconds, respectively (P