阈下条件电刺激对患者心脏不应期和起搏节律的影响

目的研究阈下条件电刺激对心脏不应期的影响。方法通过右心电极导管法,在24例心律失常患者中,观察阈下条件单个刺激（Ss）和串刺激（St）对心房或心室不应期和心房或心室起搏节律的影响。结果在SlS2间期中加发St,可使人心房及心室相对不应期和有效不应期延长;且随St强度的增加,不应期延长量增加。在SlS2间期中加发Ss,只有6/18例,心房相对不应期延长;另6/18例,心室相对及有效不应期延长。另外,St和Ss可抑制心房及心室起搏节律。结论阈下条件电刺激具有抑制心肌兴奋性的作用。

Effect of subthreshold conditioning stimulation on refractory period and pacing rhythm in human heart

AIM:To study effect of subthreshold conditioning stimulation on refractory period and pacing rhythm in human heart.METHODS: Effects of subthreshold conditioning single stimulation(S_s ) and train stimulation(S_t ) on atrial or ventricular refractory period and atrial or ventricular pacing rhythm were observed by the mothod of right heart electrode catheter in 24 cases. RESULTS: That S_t introduced into S_1 -S_2 interval(refractory period) could prolong atrial and ventricular relative refractory period(RRP) and effective refractory period(ERP).Increase of voltage strength of S_t was followed by increase of prolongated value of atrial and ventriclar refractory period.That S_s introduced into S_1 -S_2 interval could cause prolongation of atrial relative RRP in only 6/18 cases and prolongation of ventricular RRP and ERP in only 6/18 cases respectively.On the other hand,S_t and S_s could also inhibit atrial and ventricular pacing rhythm.CONCLUSION: Subthreshold conditioning stimulation may have inhibitive effect on myocardial excitability.