钙对心房肌电重构影响的实验研究

Experimental study of calcium on atrial electrical remodeling

目的 用动物试验模拟快速房律 ,观察心房电重构的电生理变化并对其机制进行初步的探讨。方法 用 8只羊自身随机对照 ,观察不同状态下和用不同药物时心房有效不应期 (AERP)的变化 ,和心房颤动 (房颤 )的诱发率。结果 (1) 80 0次 /min的快速心房刺激很快引起AERP的缩短 ,停止刺激后AERP的恢复也很快。单用维拉帕米可防止快速刺激引起AERP的缩短 ,而升高血清钙显著延缓停止刺激后的AERP的恢复 ,而且升高血清钙可消除维拉帕米对AERP的保护作用。 (2 )快速心房刺激后明显增加心房反复激动和房颤的诱发率。结论 ① 7h、80 0次 /min的快速刺激可造成心房电重构 ,电重构出现较早 (30min内 ) ,停止刺激后电重构很快恢复 (1h内 ) ;②心房电重构后容易诱发心房反复激动和房颤 ;③维拉帕米可预防心房电重构 ,升高血钙可延缓电重构的恢复。

Objective To test the phenomenon and mechanism of atrial electrical remodeling in lab animals. Methods Eight sheep, auto randomized controlled, were observed in the changes of atrial effective refractory period (AERP) under different conditions and after administered different drugs. Results 1. Changes of AERP: There was a prompt decrease in AERP as the result of rapid pacing, for the first 30 minutes, the decrease was 29-36 ms, then the AERP shortened by an average of 1-2 ms/h. The time of electrical remodeling after cessation of rapid pacing was comparable to the onset kinetics, The AERP recovered to 86% of AERP pre pacing 1 hour later. Verapamil administration completely abolished the shortening of AERP caused by rapid pacing, while increased serum calcium delayed the recovery of AERP after cessation of pacing, and it eliminated the protection of verapamil for the electrical remodeling. 2. Effects on RAF and AF inducibility: Rapid pacing significantly increased RAF and AF inducibility, which was recovered to normal after the cessation of pacing 1 hour later. Conclusions (1) 7 hours of rapid pacing (800/min) could induce atrial electrical remodeling, which might occur soon (within 30 minutes), and recover quickly after the cessation of pacing (within 1 hour); (2) Rapid pacing could increase RAF and AF inducibility; (3) Verapamil could prevent atrial electrical remodeling, while increased serum calcium could delay the recovery.