改变左心室后负荷和离体兔心脏对阈下条件串刺激引起的心室不应期变化的影响

目的:探讨改变左心室后负荷和兔离体灌注心脏对阈下条件串刺激引起的心室不应期变化的影响。方法:采用阈下条件刺激(S_t)法心室不应期测定技术,测定改变左心室后负荷和去除神经,体液因素作用时,S_t法心室不应期强度间期关系特征。结果:减小左室后负荷,可使S_t法测定的心室不应期延长(P＜ 0.05, P＜ 0.01);且在各刺激强度的S_t,S_t(200 Hz,100 ms)和S_t(50 ms, 100 Hz)测定的心室不应期最长(P＜ 0.05,P＜0.01)。结论:改变左心室后负荷和去除神经体液因素作用可使S_t法心室不应期强度间期关系特征发生改变。

Effect of changing left ventricular afterload and isolated perfused rabbit heart on ventricular refractory period measured by subthreshold conditioning train stimulation

AIM: To study the effect of changing left ventricular afterload and isolated perfused rabbit heart on ventricular refractory period measured by subhthreshold conditioning train stimulation (St).METHODS:Ventricu- lar refractory pened strength- interval relation was measured by St method under the condition of changine left ven- tricular afterload and elimination action of nervous and body fluid.RESULTS: Reducing left ventricular afterload pro -longed ventricular refractory period measured by St method (P < 0.05, P < 0.01). and St(200 Hz, 100 ms) and St(50 ms, 100 Hz) caused maximal prolongation of ventricular refractory period (P < 0 .05, P < 0. 01 ).CONCLU- SION: Changing left ventricular afterload and eliminating action of nervous and body fluid could cause alteration of characteristic of ventricular refractory period strength-interveal relation measured by S1 method.