增龄对房颤犬心房有效不应期的影响

The influence of aging on atrial effective refractory period in dogs with atrial fibrillation

目的探讨增龄对房颤犬心房有效不应期(AERP)的影响。方法 24只健康比格犬,按年龄及是否采用起搏器造成房颤模型分为老龄房颤组、成年房颤组、老龄窦律组及成年窦律组。在基础刺激分别为400、350、300及250ms时测定左房AERP及AERP频率自适应性。关闭起搏器或通过期前程序刺激和高频刺激进行诱发测定房颤持续时间。结果成年房颤组较成年窦律组AERP呈缩短趋势,除400ms周长外,随着Sl刺激周长的缩短,AERP缩短越发明显(P<0.05);老龄房颤组较老龄窦律组左房的AERP逐渐延长,差异均有统计学意义(P<0.05);不同基础S1起搏时老龄房颤组AERP均较成年房颤组延长(P<0.05)。老龄房颤组在300、250ms周长起搏时左房AERP频率自适应性较成年窦律组、成年房颤组、老龄窦律组差值更加明显(P<0.05)。老龄房颤组负荷也明显增加(P<0.05)。结论增龄性房颤时AERP延长、AERP频率自适应性不良可导致房颤的易感性和持续性增加。

Objective To investigate the effect of aging on atrial effective refractory period（AERP）in atrial fibrillation dogs.Methods Twenty-four healthy dogs were divided into atrial fibrillation group,adult atrial fibrillation group,old age sinus rhythm group and adult sinus rhythm group according to age and whether the pacemaker was used.The left atrial AERP and AERP frequency self-adaptability were measured when the basic pacing cycle length（BCLs）were 400 ms,350 ms,300 ms,and 250 ms,respectively.Atrial fibrillation persistent time was measured at the same time.Results Compared with the adult control group,the AERP of the adult AF group showed a trend of shortening.With Sl stimulus length shortening,the AERP shortened significantly（P〈0.05）.However,in the elderly AF group,AERP of the left atrium was gradually prolonged compared with the old control group.Compared with the adult controls,adult atrial fibrillation and older controls,the self-adaptiveness of left atrial AERP in the elderly dogs was significantly longer at 300 ms and 250 ms pacing of CLs（P〈0.05）.The duration of atrial fibrillation was significantly longer in the elderly AF group（P〈0.05）.Conclusion AERP prolongs in age-related atrial fibrillation,and self-adaptation of AERP frequency is poor,which may lead to increased susceptibility and duration of atrial fibrillation.