起搏周期突然改变对窦房结有效不应期的影响

The effect of abrupt changes in pacing cycle length on the sinus node effective refractorv neriod in man

目的:研究起搏周期(PCL)突然改变对窦房结有效不应期(SNERP)的影晌及临床意义。方法:对照组34例,病窦组31例,经食管心房 S_1-S_1-S_2刺激法测定 SNERP。试验起搏周期(PCLt)选择 PCLt/PCL=1.10、1.05、1.00、0.95、0.90共5个周期。结果:随着 PCLt 突然缩短,全部对照组及92.3%的病窦组 SNERP 延长;而随着 PCLt 突然延长,70%对照组与61.5%病窦组 SNERP 缩短,其余 SNERP 无变化或轻微延长。按 PCLt 与SNERP 关系的散点趋势作直线回归分折,病窦组斜率为-0.17±0.03(P<0.01),对照组斜率为-0.36±0.05(P<0.01),两组差异有显著性(P<0.01),且重叠区不明显。结论:PCLt 突然改变对 SNERP 的影响与 PCL 对SNERP 的影响相似。PCLt 与 SNERP 关系的斜率可考虑作为一项诊断窦房结兴奋性减退的临床指标。

Objective:To study the effect of abrupt changes in pacing cycle length(PCL)on the sinus node effective refractory period(SNERP)in man.Methods:65 cases(31 sick sinus syndrome group,34 control group)were measured for SNERP with S_1-S_1'-S_2 programmed extrastimulus with transesphageal atrial pacing,and 5 test pacing cycle length(PCLt)were selected(PCLt/PCL= 1.10,1.05,1.00,0.95,0.90).Results:With the abrupt decrease of PCLt,SNERP prolonged,and with the abrupt prolong of PCLt,SNERP shorted in 66% cases,had no changes or slightly prolonged in 34% cases.The results were in accordance with the properties of linear regression.The slopes((?)± s)were-0.17±0.03(P<0.01)in sick sinus syndrome group and-0.36±0.05(P<0.01)in control group.There was a significant difference in slopes in two groups(P<0.01).Conclusion: Effect of abrupt changes in PCLt on SNERP Was similar to those of changes of PCL.It may be consid- ered that the slope could be used as a clinic parameter of assessment of sinoatrial refractoriness in the diagnosis of patients with sick sinus syndrome.