Age-associated changes in electrophysiologic remodeling: a potential contributor to initiation of atrial fibrillation
Age-associated changes in electrophysiologic remodeling: a potential contributor to initiation of atrial fibrillation
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DOI：
10.1016/j.cardiores.2004.10.033
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发表时间：
2005-05-01
影响因子：
10.8
通讯作者：
Rosen, MR
中科院分区：
文献类型：
--
作者：
Anyukhovsky, EP;Sosunov, EA;Rosen, MR
目的：虽然心房颤动(房颤)的发生率随着年龄的增长而增加，但使老年人的心房更容易发生房颤的细胞电生理变化仍然知之甚少。我们假设心房复极离散度随着年龄的增长而增加，为房颤的发生创造了底物。方法：实验分为4组：正常窦性心律(SR)的成年和老年犬和快速心房起搏诱发的成年和老年慢性房颤(CAF)犬。用微电极记录犬右心房四区和左心房三区心内膜分离标本的动作电位。通过计算标准差(SD)和变异系数(COV[SD/Mean]x 100%)，获得每只犬AP时程异质性的两个指标。结果：在SR组中，老年组各部位AP时程的平均值明显长于成人组织。与成年犬相比，老年犬的两个动作电位异质性指数均较高。在这两个年龄段，CAF与显著的时程缩短和时程适应性降低有关。CAF显著增加成年犬的两个时程异质性指标，显著降低老年犬的时程异质性。结论：老年犬心房复极的空间变异性增加可能参与了老年房颤的发生。CAF诱发的时程缩短和时程适应性的降低对于维持成人和老年房颤的持续性是很重要的。CAF引起的复极离散度的增加对成人房颤的稳定可能是重要的，而先前报道的纤维化和早搏传导减慢可能是老年人在SR期间启动房颤和随后的房颤稳定的重要因素。(C)2004年欧洲心脏病学会。爱思唯尔出版，版权所有。
Objective: Although the incidence of atrial fibrillation (AF) increases with age, the cellular electrophysiological changes that render the atria of aged individuals more susceptible to AF remain poorly understood. We hypothesized that dispersion of atrial repolarization increases with aging, creating a substrate for initiation of AF.Methods: Four groups of dogs were studied: adult and old dogs in normal sinus rhythm (SR) and adult and old dogs with chronic AF (CAF) induced by rapid atrial pacing. In each dog, action potentials (AP) were recorded with microelectrodes from isolated endocardial preparations of four regions of right atrium and three regions of left atrium. Two indices of AP duration (APD) heterogeneity were obtained in each dog by calculating standard deviation (SD) and the coefficient of variation (COV [SD/mean] x 100%).Results: In SR groups, APD averaged across all regions was significantly longer in old than in adult tissues. Both indices of APD heterogeneity were higher in old dogs in comparison to adult. At both ages, CAF was associated with significant APD shortening and a decrease in APD adaptation to rate. While CAF significantly increased both indices of APD heterogeneity in adult dogs, it significantly decreased them in old dogs.Conclusions: The increase of spatial variability in repolarization in old atria may contribute to the initiation of AF in the aged. CAF-induced APD shortening and a decrease in APD adaptation appear to be important for the maintenance of sustained AF in both adult and old atria. The CAF-induced increase in dispersion of repolarization may be important for AF stabilization in adults, while previously reported fibrosis and slowed conduction of premature beats may be important in the old for both AF initiation during SR and subsequent stabilization of AF. (c) 2004 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.