心房间传导延迟对猪左心房血流动力学及机械功能的影响

Cardiac hemodynamics and mechanical function of left atrium in swine with interatrial conduction delay

目的探讨心房间传导延迟对小型猪的左心房血流动力学及机械运动功能的影响。方法8只巴马猪在三维电解剖标测系统指引下,在右心房内膜面尝试进行经导管射频消融Bachmann传导束,建立心房间传导延迟模型(消融建模不成功设立为对照组)。通过超声心动图记录左心房机械功能参数,使用Swan-Ganz导管测定血流动力学参数,对比消融建模后即刻(急性期)以及消融后3个月(慢性期)与消融前左心房最大容积、左心房扩大指数、肺毛细血管楔压及心排出量等参数的变化。结果5只猪心房间传导延迟模型建模成功(延迟组),P波宽度从消融术前(69.4±2.9)ms延长至术后(113.4±4.5)ms及术后3个月(115.8±3.9)ms(P<0.001);另外3只猪P波未见明显改变(P=0.47)。延迟组肺毛细血管楔压在消融术后慢性期较消融前明显增加[(18.0±1.8)mmHg(1mmHg=0.133kPa)对(11.2±1.3)mmHg;P<0.001],对照组肺毛细血管楔压则未发生显著变化[(12.3±0.5)mmHg对(12.0±1.0)mmHg;P=0.79]。两组左心房机械运动功能参数改变差异无统计学意义(P均>0.05)。结论心房间传导延迟可导致肺毛细血管楔压显著升高,此可能是射血分数保留心力衰竭的发病原因之一。

Objective To explore the impact of interatrial conduction delay(IACD)on the cardiac hemodynamics and mechanical function of left atrium(LA)in swine.Methods Eight swine underwent radiofrequency catheter ablation for the Bachmann bundle on the right atrial endocardium.Echocardiogram and invasive Swan-Ganz were performed to measure the parameters of cardiac hemodynamics and mechanical function of LA before and instantly after the ablation.Three months later,all these parameters were measured again and compared,respectively.Results Five swine were successfully modulated as IACD(delay group)and the others were assigned to the control group.P-wave duration(PD)prolonged either instantly after the ablation or three months later[(69.4±2.9)ms vs.(113.4±4.5)ms vs.(115.8±3.9)ms,respectively;P<0.001]in the delay group.However,PD failed to prolong remarkably(P=0.47)in the control group.Pulmonary capillary wedge pressure(PCWP)increased greatly[(18.0±1.8)mmHg vs.(11.2±1.3)mmHg;P<0.001]three months later in the delay group but at remained at the same level as before in the control group[(12.3±0.5)mmHg vs.(12.0±1.0)mmHg,P=0.79].There was no significant difference in LA mechanical motion between the two groups(P>0.05).Conclusion IACD could lead to PCWP increasing in the chronic phase,which might be partly the pathogenesis of heart failure with preserved ejection fraction.