双心室绝对不应期电刺激对心力衰竭兔心功能的影响

目的观察双心室绝对不应期电刺激对慢性心力衰竭兔心功能和心室重构的影响,探讨绝对不应期电刺激,即心脏收缩调节(CCM)信号治疗慢性心力衰竭的最佳模式和安全性。方法 30只新西兰大白兔分为假手术组、左心室刺激组和双心室刺激组各10只,通过升主动脉根部套扎法建立慢性心力衰竭模型,之后对左心室刺激组和双心室刺激组发放CCM信号,每天刺激6 h,连续刺激7 d,于电刺激前后观察心室结构、心脏功能及CCM信号刺激的心电学方面变化。结果与假手术组相比,左心室刺激组和双心室刺激组心脏质量、心脏质量指数、左心室收缩末内径、左心室舒张末内径和血浆脑利钠肽水平均下降(5.23±0.56)g和(4.41±0.36)g比(6.72±0.82)g;(1.41±0.27)g/kg和(1.18±0.17)g/kg比(1.82±0.25)g/kg;(10.26±0.49)mm和(8.95±0.41)mm比(11.76±0.49)mm;(13.54±0.53)mm和(12.50±0.71)mm比(14.32±0.71)mm;(52.9±13.7)ng/ml和(41.3±13.4)ng/ml比(66.3±12.5)ng/ml,均为P<0.05],以双心室刺激组下降更明显;而左心室射血分数和左心室短轴缩短率明显升高(46.50%±4.31%和55.75%±4.53%比37.00%±3.10%;24.21%±2.94%和28.20%±2.67%比17.90%±1.69%,均为P<0.05),以双心室刺激组升高更明显。各组刺激前后室间隔厚度、左心室后壁厚度、E峰、A峰和E/A比值未见明显变化;24 h动态心电图显示,左心室刺激组和双心室刺激组发放CCM信号时与关闭信号时相比未见心率变化,而与假手术组相比,未见室性心律失常增加。结论双心室绝对不应期电刺激可增加慢性心力衰竭者的心肌收缩力,改善心功能,逆转心室重构,且不增加室性心律失常的发生,较单心室电刺激有更大优势。

Effects of biventricular electric stimulations during absolute refractory period on cardiac function of rabbits with heart failure

Objective To investigate the effects of biventricular electric stimulations during absolute refractory period(ARP) on cardiac function and ventricular remodeling of rabbits with chronic heart failure,and to explore the best pattern and the safety of Cardiac Contractility Modulation(CCM).Methods Thirty rabbits were divided into three groups:sham-operation group,LV cardiac contractility modulation(LV-CCM) group,biventricular cardiac contractility modulation(BV-CCM) group.Rabbit models of chronic heart failure were made by ligating ascending aortic root.Then electrical stimulations during the absolute refractory period were delivered on the anterior wall of left ventricle in LV-CCM group and on the anterior wall of both left ventricle and right ventricle in BV-CCM group lasting six hours everyday for seven days.Changes in ventricular structure,cardiac function and electrocardiology were observed before and after CCM stimulation.Results Compared with sham-operation group,heart weight,heart weight index,LVESD,LVEDD and Plasma BNP levels in LV-CCM and BV-CCM group were significantly decreased (5.23±0.56)g and(4.41±0.36)g vs.(6.72±0.82)g;(1.41±0.27) g/kg and(1.18±0.17) g/kg vs.(1.82±0.25) g/kg;(10.26±0.49) mm and(8.95±0.41) mm vs.(11.76±0.49) mm;(13.54±0.53) mm and(12.50±0.71) mm vs.(14.32±0.71) mm;(52.9± 13.7)ng/ml and(41.3±13.4) ng/ml vs.(66.31±12.46) ng/ml,all P<0.05],and LVEF and FS were significantly increased (46.50%±4.31%) and(55.75%±4.53%) vs.(37.00%±3.10%);(24.21%±2.94%) and(28.20%±2.67%) vs.(17.90%±1.69%),all P<0.05],especially in BV-CCM.IVS,LVPM,E wave,A wave and E/A ratio were similar before and after CCM delivered among three groups(P>0.05).Compared with sham-operation group,heart rate had no change and there was no increase in ventricular arrhythmias in LV-CCM and BV-CCM group.Conclusions Biventricular electric stimulations delivered during the ARP is safe and can significantly enhance the contractility of myocardium,improve cardiac function and reverse ventricular remodeling.