Tang Min, Zhang Shu, Sun Qi, Huang Congxin
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, Beijing, China.
Circ J. 2007 Oct;71(10):1636-42. doi: 10.1253/circj.71.1636.
Chronic left atrial dilatation (CDLA) is associated with an increased incidence of atrial fibrillation (AF). The electrophysiological functions of the left atrial posterior wall (LAPW) are not well understood.
Eight control dogs and 8 with CDLA (developed 6 months after partial mitral valve avulsion) were studied. An electrophysiological study was performed using the noncontact mapping system. The conduction velocity was significantly decreased in the LAPW in the CDLA group. During atrial extrastimulation, a sharp curvature in the activation wavefront became apparent in the LAPW of 6 CDLA dogs, with unidirectional block in 1 dog. The effective refractory periods increased homogeneously throughout the atrium in the CDLA group. AF was much more easily inducible in the CDLA dogs than in the controls. After the onset of AF, the LAPW exhibited the earliest disorganized activity as compared with other sites in the left atrial. In the CDLA dogs, the most extensive interstitial fibrosis was observed in the LAPW.
Alterations in the electrophysiologic properties and tissue structure of the LAPW were observed in the CDLA dogs. This study supports the idea that the LAPW may play a role in the mechanism of AF induced by CDLA.
慢性左心房扩张（CDLA）与心房颤动（AF）发病率增加相关。左心房后壁（LAPW）的电生理功能尚未完全明确。
研究了8只对照犬和8只患有CDLA的犬（二尖瓣部分撕脱术后6个月形成）。使用非接触式标测系统进行电生理研究。CDLA组LAPW的传导速度显著降低。在心房额外刺激期间，6只CDLA犬的LAPW中激活波前出现明显的急剧弯曲，1只犬出现单向阻滞。CDLA组整个心房的有效不应期均匀增加。与对照组相比，CDLA犬更容易诱发AF。AF发作后，与左心房其他部位相比，LAPW表现出最早的紊乱活动。在CDLA犬中，LAPW观察到最广泛的间质纤维化。
在CDLA犬中观察到LAPW电生理特性和组织结构的改变。本研究支持LAPW可能在CDLA诱发AF的机制中起作用这一观点。
