钙瞬变交替在房颤形成中的作用

摘要

[Objective] To study the effect of calcium transient alternan on the atria] fibrillation by rapid atrial pacing in canine. [Methods] Rapid atrial pacing group (RAP group) and control group were involved. Atrial myocytes were isolated. The calcium transient in different frequent stimulation was studied using laser scan confocal microscope (LSCM). The time parameters of calcium transient and the threshold stimulative frequency of calcium transient alternan were measured. [Results] Comparing to control group, the threshold stimulative frequency (min-1) of calcium transient alteman in RAP group was significantly lower (86±17 vs l23± 11, P < 0.01). And the atrial myocytes in RAP group more easily develop to subcellular disconcordant calcium transient alteman. Under the condition of 30 min-1 stimulation, the time to peak (ms) of calcium transient was significantly longer in RAP group (123 ± 1 vs 1110± 13 ,P = 0.001) , but the 90% decay time (ms) was not different (451 ± 79 vs 466 ± 81, P = 0.514). [Conclusions] Calcium transint alternan is correlated with rapid atrial pacing which is prone to atrial fibrillation. Calcium transient alternan may play an role in the formation of atrial fibrillation and may be determinated by L-type calcium channel (LCC), ryanodine receptor (RyR) or their coupling.%[目的]观察钙瞬变交替在快速心房起搏的犬心房肌细胞中的变化情况，探讨钙瞬变交替在房颤形成中的作用。[方法]制成快速心房起搏的致房颤犬动物模型，分成快速心房起搏组与对照组。分离心房肌细胞，使用激光扫描共聚焦显微镜测定在不同频率的电场刺激下，心房肌细胞的钙瞬变及钙瞬变交替出现的阈值频率。[结果]快速心房起搏组心房肌细胞钙瞬变交替的阈值频率(min-1)明显低于对照组(86±17 vs 123±11，P＜0.01)，同时易产生亚细胞非同步性钙瞬变交替。在30 min-1的频率刺激下，快速起搏的心房肌细胞钙瞬变的达峰时间(ms)明显延长(123±1 vs 110±13，P=0.001)，但90％的恢复时间(ms)则无统计学差异(451±79 vs 466±81，P=0.514)。[结论]快速心房起搏的心房肌细胞易发生钙瞬变交替，钙瞬变交替可能参与了房颤的形成,钙瞬变交替的时间可能与LCC、RyR或其耦联异常有关。