室性早搏对左心功能影响的实验研究

本文应用心室起搏方法,在12只清醒犬研究了不同刺激部位(左室前、后壁及右室流出道)和连结间隔的室性早搏对左室功能的影响。发现,室性早搏与对照比较,左室收缩压峰值(LVSP)在各刺激部位和连结间隔基本上没有变化;左室压变化速率(LV dp/dt)和每搏输出量(SV)在各部位短连结间隔显著降低;左室舒张期末压(LVEDP)仅在刺激左室前、后壁的短连结间隔显著减少。室性早搏与早搏后代偿收缩相比,LVSP 在各剌激部位的短连结间隔显著降低;LVEDP和 dp/dt,在各刺激部位和连结间隔都显著降低;SV,除右室流出道的长连结间隔外,均显著降低。并且,这些变化与刺激部位和连结间隔密切相关。总之,实验证明,室性早搏可使左室心肌收缩性能和泵功能降低,而且,右室功能状态也可影响左室机能。

EXPERIMENT STUDIES OF THE EFFECT OF PREMATURE VENTRICULAR CONTRACTION ON LEFT VENTRICULAR FUNCTION

The effect of premature ventricular contraction (PVC) in different stimulation sites,including the left ventricular anter- ior wall (LVAW),the left ventricular po- sterior wall (LVPW) and the right ventri- cular outflow tract (RVO),and the cou- pling intervals induced by the ventricular pacing on the left ventricular function were studied in 12 conscious dogs,The ven- tricular pacing produced no significant changes in the left ventricular systolic pr- essure (LVSP) in different intervals and sites an obvious reduction in peak dp/dt and stroke volume (SV) in short coupling intervals at each site,as well as an evid- ent reduction in the left ventricular end- diastolic pressure (LVEDP) at LVAW and LVPW stimulation,compared with the con- trol group.However,LVEDP and peak dp/dt in different intervals at each site, LVSP in short intervals at each site and SV in all intervals and sites except long intervals at RVO were all reduced signifi- cantly in PVC than in.postextrasystolic contraction.Moreover,these changes highly related to the stimulation site and coupling intervals,suggesting that PVC produced a significant reduction in the myocardial contraction and pump function of LV.The disturbance of the right ventricular func- tion also may affect the left ventricular function.