自主神经干预对心房恢复性质的影响

Effects of autonomic interventions on atrial restitution properties

目的 研究心脏自主神经干预对心房恢复性质的影响.方法 正常成年杂种犬10只,开胸后将多极电生理导管缝置于肺静脉、左右心耳和左右心房处,应用Ag-AgCl电极记录标测部位单相动作电位,在基础状态和颈部迷走神经刺激条件下构建标测部位恢复曲线,分别对标测部位进行快速电刺激,记录心房颤动（房颤）诱发时的起搏周长和持续时间.心脏自主神经节（GP）消融后重复上述步骤.结果 GP消融前迷走神经刺激同基础状态相比显著缩短动作电位时限（APD）,降低恢复曲线最大斜率（Smax）,抑制APD电交替,但房颤容易发生（P＜0.05）.GP消融后,APD较消融前显著延长,恢复曲线Smax增大,APD电交替提前,但房颤不易诱发（P＜0.05）;GP消融后迷走神经刺激效应明显减弱.GP消融前迷走神经刺激能显著增加APD恢复曲线Smax离散度（0.5±0.2对0.3±0.1,P＜0.05）,而GP消融能显著降低APD恢复曲线Smax离散度（0.2±0.1对0.3±0.1,P＜0.05）.结论 恢复曲线的斜率并不能完全解释房颤的诱发和维持,心房APD电交替可能对房颤的诱发并无预测作用,恢复性质的离散可能是诱发房颤的重要因素.

Objective This study aimed to investigate the effects of autonomic interventions on the restitution properties on the atria. Methods In 10 open-chest dogs,multiple electrode catheters were sutured at multiple pulmonary vein（PV） and atrial sites. The monophasic action potential was recorded by an AgAgCl catheter. The restitution curve at each site was constructed before and after vagal stimulation or ganglionated plexi（GP） ablation. The atrial fibrillation（AF） inducibility and duration induced by burst pacing were measured at each site before and after ipsolateral vagal stimulation or GP ablation. Results Before GP ablation, vagal stimulation markedly shortened the action potential duration （APD）, decreased the slope of the restitution curves and the APD alternans cycle length, while increased the AF inducibility and duration once induced at each site（ P 〈 0. 05 ）. These effects were eliminated by GP ablation. Compared to baseline,GP ablation significantly increased the APD, steepened the restitution curves and facilitated the APD alternans while decreased the AF inducibility and duration （ P 〈 0. 05 ）. VNS significantly increased （ 0. 5 ± 0. 2 vs. 0. 3 ±0. 1 ,P 〈 0. 05 ） and GP ablation decreased （0. 2 ± 0. 1 vs. 0. 3 ± 0. 1, P 〈 0. 05 ） the spatial dispersion of the slopes of APD restitution curves, respectively. Conclusions The maximal slope of APD restitution curve alone does not fully account for the changes of AF inducibility and duration induced by autonomic interventions; instead, the spatial dispersion of the APD restitution curves of Smax may be an important determinant for susceptibility of AF.