【摘要】 目的:探讨肺静脉电保护作用的机制。方法:健康杂种犬8只,开胸,暴露心脏及左上肺静脉,把自制电极置于肺静脉外膜上,分别在起搏周长为300 m s,200 m s下测定肺静脉长轴上四个部位的有效不应期,在相同起搏周长下比较肺静脉四部位有效不应期的大小。结果:在相同起搏周长下,PV 1.8与PV 2.7,PV 2.7与PV 3.6,PV 3.6与PV 4.5的有效不应期相比差异均有统计学意义(P<0.01)。结论:肺静脉近端有效不应期较长,从肺静脉口进入肺静脉越深,有效不应期越短。肺静脉近端较长的有效不应期可能是肺静脉电保护作用的机制之一。更多还原

【Abstract】 Objective To investigate the mechanism of pulmonary vein electrical protection.Methods Eight healthy dogs received chest open operation and heart and left superior pulmonary vein exposure.The annular electrode was placed in the adventitia of the left superior pulmonary veins.Effective refractory periods at four sites of Pulmonary vein were measured with S₁S₂ programmed electrical stimulation at two different pacing cycle length 300 ms and 200 ms.Effective refractory periods at different sites were compared at the same pacing cycle length.Results At the same pacing cycle length,effective refractory period at site of PV1.8 was much longer than that at site of PV2.7（P<0.01）,effective refractory period at site of PV2.7 was much longer than that at site of PV3.6（P<0.01）,and effective refractory period at site of PV3.6 was much longer than that at site of PV4.5（P<0.01）.Conclusion effective refractory period at the proximate pulmonary vein is much longer than that at the distal pulmonary vein.From proximate pulmonary vein to distal pulmonary vein,effective refractory period becomes short gradually.The longer effective refractory period at proximate pulmonary vein is possibly one of mechanisms of pulmonary vein electrical protection.更多还原