超声监测呼吸对风湿性心脏病患者二尖瓣血流速度的影响及对相关力学机制的分析

Effects of respiration on mitral inflow velocity by ultrasound in patients with rheumatic heart disease and its mechanics

目的探讨呼吸对风湿性心脏病单纯二尖瓣狭窄患者二尖瓣血流速度的影响及其力学机制的研究。方法选取32例风湿性心脏病单纯二尖瓣狭窄患者(风湿性心脏病组)和30例正常成人(对照组),应用经胸超声心动图检查分别获取吸气相与呼气相时二尖瓣和三尖瓣彩色多普勒血流频谱,测量舒张早期血流速度峰值(E、Et)及舒张晚期血流速度峰值(A、At),并比较吸气相与呼气相各参数之间的差异。结果对照组吸气相较呼气相E值减低,Et值增大,差异有统计学意义(P<0.01),风湿性心脏病组吸气相较呼气相E和Et值增大,差异有统计学意义(P<0.01),两组A和At值均无变化。结论呼吸对正常人成与风湿性心脏病单纯二尖瓣狭窄患者二尖瓣血流速度的影响不同。吸气时胸内负压的直接力学作用与左室舒张方向相同,有利于左室舒张,可能是风湿性心脏病单纯二尖瓣狭窄患者二尖瓣血流速度E峰值增大的原因。

Objective To explore the effects of respiration on mitral inflow velocity by ultrasound in patients with rheumatic heart disease and its potential mechanics.Methods Thirty-two patients with rheumatic mitral stenosisand（rheumatic heart disease group） and thirty healthy subjects（control group） were underwent echocardiography in apical four-chamber heart view.The inspiratory and expiratory phase of mitral Doppler spectrum,early diastolic flow velocity E（E,Et） and late diastolic flow velocity A（A,At） were obtained respectively,the parameters between inspiratory phase and expiratory phase were compared. Results For control group,compared with expiratory phase,E in inspiratory phase was decreased,Et was increased,there was significant difference（P〈0.01）. For rheumatic heart disease group,compared with expiratory phase,E and Et in inspiratory phase were increased,there was significant difference（P〈0.01）,A and At did not change in the both two group.Conclusion Breathing has different effects on mitral in flow velocity in normal people and rheumatic heart disease patients with pure mitral stenosis. Direct mechanical effect of increasing negative intrathoracic pressure during inspiratory phase has the same movement direction as left ventricular diastole,in favor of left ventricular relaxation,which may be the reason that lead to the increases of mitral in flow velocity E in patients with rheumatic mitral stenosis.