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目的探讨左房快速起搏对肺静脉口、左右心耳电重构的影响。方法运用快速起搏左心耳的方法建立心房颤动(AF)模型,在起搏前及起搏后的第1,3,5,7d对左、右心耳;左上、左下肺静脉口;右上、右下肺静脉口的有效不应期(ERP)、ERP频率适应性、ERP离散度及心房间的传导时间进行测定。采用S1S2程序刺激,基础起搏周长(PCL)分别为400,300,200ms,S2为200ms,以5ms的步长递减。程序刺激结合Burst刺激对上述心房部位进行AF的诱发,记录AF的发生率。在第8天关闭起搏器,采用上述相同方法对起搏停止后即刻;2,4,6,24h的上述各部位的ERP进行测定。结果起搏1d后各个基础起搏周长下各部位的ERP明显缩短,ERP频率适应性降低,ERP离散度增大(P<0.05),而心房间传导时间无明显变化(P>0.05);起搏终止后各部位的ERP逐渐延长,但起搏终止后6hERP与快速起搏前相比仍有明显缩短(P<0.05);24h后ERP基本恢复到起搏前水平,两者相比无明显差异(p>0.05);随着起搏时间的延长各部位AF的诱发率逐渐增高(P<0.05)。结论快速心房起搏不仅引起心房肌电重构,亦引起肺静脉电重构。
Objective To investigate the effect of rapid atrial pacing in left atrium on pulmonary vein ostial remodeling. Methods Atrial fibrillation (AF) model was established by rapid pacing left atrial appendage. Left and right atrial appendage were collected before pacing and 1, 3, 5 and 7 days after pacing. Left and right lower pulmonary veins were opened. Right upper and lower right The effective refractory period (ERP) of the pulmonary veins, ERP frequency adaptability, ERP dispersion and atrial conduction time were measured. Stimulated by S1S2 program, basal pacing circumference (PCL) were 400,300,200 ms, S2 was 200 ms, decreasing in steps of 5 ms. Procedural stimulation combined with Burst stimulation of the atrial parts of the AF induced by the record of the incidence of AF. The pacemaker was switched off on day 8 and immediately after pacing was stopped in the same manner as described above. The ERP at each of these sites was measured at 2, 4, 6, 24 hours. Results After 1 day of pacing, the ERP of each part under each basic pacing circumference was significantly shortened, the adaptability of ERP frequency was reduced, ERP dispersion was increased (P <0.05), and there was no significant change in the conduction time between the two groups (P> 0.05). After the termination of pacing, the ERP of each site gradually extended, but 6 hERP after pacing termination was still significantly shorter than that before rapid pacing (P <0.05); ERP recovered to pre-pacing level after 24 h (P> 0.05). With the extension of pacing time, the induction rate of AF increased gradually (P <0.05). Conclusions Rapid atrial pacing not only causes atrial myoelectrical remodeling but also induces pulmonary venous remodeling.