慢-快综合征心房电重构和逆向电重构现象的实验研究

Experimental study on atrial electrical remodefing and reverse electrical remodeling in canine model of slow-fast syndrome

目的：建立犬窦房结功能不良（SND）下心房快速刺激心房颤动（房颤）的模型，探讨缓慢心律失常下慢-快综合征发生的心房电重构和逆向电重构现象。方法：12只健康成年犬用甲醛损伤犬窦房结建立SND模型，于左、右心房外膜7个部位自身前后对照观察心房有效不应期（AERP）变化及离散度、房颤的诱发率及AERP的恢复过程。结果：SND和心房快速刺激可导致犬心房各部位AERP缩短，AERP离散度增高。心房快速刺激终止后，AERP逐渐恢复，且左心耳AERP恢复过程慢于右心耳。低位右心房及左心耳部位的期前兴奋更易诱发房颤。结论：SND可致心房各部位AERP缩短且程度不同，是SND时易发生房颤的电生理基础，SND本身引起的心房电重构是慢-快综合征发生的重要机制，心脏电学顿抑是重要的电生理学现象。

Objective To study electrical remodeling （ER） and reverse electrical remodeling （RER） in sinus node dysfunction （SND） after rapid atrial pacing. Methods Model of SND was established by contact cotton with formaldehyde to surface area of sinus node in 12 dogs. Atrial effective refractory （AERP） and dispersion of AERP, inducible rate of AF, and recovery of shortened AERP were observed in 7 epicardium sites in left and right atria before and after rapid atrial pacing. Results AERPs in 7 sites were shortened and dispersions of AERP were increased in model of SND and after rapid atrial pacing. Shortened AERPs were recovered after termination of rapid atrial pacing, but the recovery in right appendage was earlier than that in left appendage. Atrial fibrillations were easy to be induced by extra-stimulus （S1S2） in low right atrium and left appendage. Conclusion SND and rapid atrial stimulation could produce ER in atrium with different degree and may be the substrate in precipitating AF. Cardiac electrical stunning is a common electrophysiological characteristic.