The mechanisms of an increased dominant frequency in the left atrial posterior wall during atrial fibrillation in acute atrial dilatation
The mechanisms of an increased dominant frequency in the left atrial posterior wall during atrial fibrillation in acute atrial dilatation
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DOI：
10.1111/j.1540-8167.2005.00297.x
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发表时间：
2006-02-01
影响因子：
2.7
通讯作者：
Chen, SA
中科院分区：
文献类型：
--
作者：
Huang, JL;Tai, CT;Chen, SA
背景：既往研究表明，起搏诱发心房颤动（AF）时，最高主导频率（DF）位于左心房（LA）。然而，急性心房扩张时房颤DF升高的机制研究较少。本研究的目的是探讨急性心房扩张期间起搏诱导AF最大DF （max DF）增加的机制。方法：8只langendorff灌注犬心脏（26 +/- 2 kg），分别将非接触球囊导管置入右心房（RA）和左心房（LA）。心房扩张前和扩张后（分别为0和15 cm H2O）的超刺激诱导心房颤动。采用快速傅立叶变换分析心房颤动时双房单极虚电图的最大DF和谐波指数（HI），得到不同心房部位的颤动周期长度。分析心房颤动期间的波前数，区域分裂频率定义为心房颤动期间不同心房区域每秒波前分裂的次数。低压区（< 0.5 mV）的百分比定义为低压区面积占心房总面积的比例。结果：心房颤动时测得心房纤颤周期，最短的纤颤周期位于左心房后壁，在急性心房扩张时变短。最大DF位于左心房后壁，在急性心房扩张期间增加（7.1 +/- 0.8 vs 8.8 +/- 2.1, P = 0.02）。LA的最大DF与波前数相关（r = 0.797, P < 0.001; r = 0.860, P < 0.001）。波前的分裂促进了新波前的形成。急性期心房低压区占比（r = 0.876, P < 0.001）。此外，与其他部位相比，后壁的低电压区比例更高。结论：急性心房扩张时，低电压区比例增加，尤其是在左心房后壁，这与房颤波前的区域分裂有关。劈裂的增加促进了新波阵面形成，导致急性心房扩张时最大DF升高。
Background: Previous studies have shown that the highest dominant frequency (DF) is located in the left atrium (LA) during atrial fibrillation (AF) in pacing-induced AF. However, there have been few studies on the mechanisms of the increased DF of AF during acute atrial dilatation. The purpose of this study was to investigate the mechanisms of the increased maximal DF (max DF) in pacing-induced AF during acute atrial dilatation.Methods: In eight Langendorff-perfused canine hearts (26 +/- 2 kg), noncontact balloon catheters were placed into the right atrium (RA) and LA, respectively. AF was induced by extrastimulation pre- and postdilatation in the atrium (0 and 15 cm H2O, respectively). Fast Fourier transformation analysis was performed to analyze the max DF and harmonic index (HI) from the bi-atrial unipolar virtual electrograms during AF. The fibrillation cycle lengths were obtained from different atrial sites. The number of wavefronts was analyzed during AF. The frequency of regional splitting was defined as the number of wavefront splits per second in different atrial regions during AF. The percentage of the low-voltage zones (< 0.5 mV) was defined as the ratio of the area of the low-voltage zones to the total atrial surface area.Results: The DF was measured during AF. The shortest fibrillation cycle length was located in the LA posterior wall and became shorter during acute atrial dilatation. The max DF was located in the LA posterior wall and increased during acute atrial dilatation (7.1 +/- 0.8 vs 8.8 +/- 2.1, P = 0.02). The max DF of the LA correlated with the wavefront number (r = 0.797, P < 0.001 predilatation; r = 0.860, P < 0.001 postdilatation). The splitting of wavefronts facilitated the formation of new wavefronts. During acute atrial percentage of the low-voltage zones (r = 0.876, P < 0.001). Furthermore, the LA posterior wall had a higher percentage of the low-voltage zones than the other sites.Conclusion: In acute atrial dilatation, the percentage of the low-voltage zones increased, especially in the LA posterior wall, which correlated with the regional splitting of the AF wavefronts. The increase in the splitting facilitated the formation of new wavefronts and resulted in a higher max DF during acute atrial dilatation.