摘要
目的通过对快速心房起搏犬的电生理特性、收缩功能及超微结构的研究,观察短时间快速心房电活动是否可引起心房重构,并探讨其在房颤持续中的作用。方法健康杂种犬17只。实验组12只,经右心耳起搏450次/min,持续5小时。快速心房刺激前后分别测量 P 波时程及心房有效不应期,并用多普勒超声评价二尖瓣前向血流变化。实验结束后取左心耳及梳状肌组织观察其超微结构。对照组5只,插入电极但不起搏,与实验组同步行各项检查。结果持续快速刺激5小时后,实验组心房有效不应期降低,P 波时程增加;二尖瓣心房收缩期血流速度降低了17%;检查发现部分心肌细胞出现肌原纤维的损失、糖原累积及线粒体大小及形状的改变;而对照组均未发现明显变化。结论短时间快速心房电活动可导致犬心房发生电重构、收缩重构及结构重构,而心房结构重构可能是心房发生电重构和收缩重构的原因之一。
Objective To evaluate atrial remodeling induced by short term pacing in a canine model. Methods Transvenous lead was inserted into the fight atrial appendage of anesthetized mongrel dogs and paced for 5 hours at 450 bpm （ n = 12）. Effective refractory period （ERP） and P-wave duration were measured before and post pacing and left ventricular pressure was monitored during the procedure. Echocardiography was performed to observe the presence or absence of spontaneous echo contrast and to assess the effect of rapid atrial pacing on atrial function. All measurements were obtained in sinus rhythm. Histology of the myocardium in left atrial trabeculae and appendages was examined by electron microscopy. Results Compared to pre-pacing status, ERP was significantly reduced [ （87. 27 ± 16.35） ms vs. （113. 27 ± 11.99）ms, P 〈0. 01 ] at a cycle length of 300 ms, P-wave duration significantly increased [ （56. 09 ± 8. 62 ） ms vs. （ 52. 09 ± 7. 63 ） ms, P 〈 0. 01 ], the peak velocity of atrial contraction significantly decreased [ （48.92 ± 10. 80） cm/s vs. （59. 25± 9.37 ） cm/s, P 〈 0. 05 ] while heart rates and left ventricular pressure were not affected post five hours rapid atrial pacing. Pacing also induced significantly cellular ultrastructures changes including myofibrils loss, glycogen accumulation, mitocondria loss and swelling. Conclusion Short term pacing resulted in atrial electrical, contractile and structural remodeling.
出处
《中华心血管病杂志》
CAS
CSCD
北大核心
2007年第2期137-140,共4页
Chinese Journal of Cardiology
基金
国家973课题(2005CB523300)
关键词
心房颤动
心脏起搏
人工
电生理学
心房
重构
Atrial fibrillation
Cardiac pacing, artificial
Electrophysiology
Heart atrium
Remodeling
