平静呼吸对室间隔缺损左向右分流影响的超声心动图研究

Echocardiographic study on the effects of respiration on left to right shunt in ventricular septal defect

目的应用超声心动图检测室间隔缺损（VSD）患者平静呼吸过程中室水平左向右分流血流速度随呼吸的变化,探讨平静呼吸对VSD患者心功能影响的机制及其临床意义。方法超声记录28例VSD患者平静呼吸时室水平左向右分流的血流速度,同步记录心电图和呼吸曲线。结果平静呼吸时,VSD患者室水平左向右分流的血流速度均于吸气相低于呼气相。结论VSD患者平静呼吸时室水平左向右分流的血流速度随呼吸时相波动而规律性变化,证明了呼吸性胸压变化是导致室间隔缺损分流速度波动性变化的主要原因。

Objective To study the velocity variation of the left to right shunt during quiet respiration and to investigate the mechanism and clinical importance of quiet respiration on cardiac function in the patients with ventricular septal defect （VSD）. Methods Pulsed-wave Doppler spectra of the velocity of the left to right shunt on ventricular level were recorded by color Doppler ultrasonography in 28 VSD patients. Electrocardiogram and respiratory tracing by a nasal thermistor were recorded simultaneously. Results The blood velocity of the shunt on ventricular level was lower in inspiration than that in expiration during quiet respiration in VSD patients. Conclusions The velocity of the left to right shunt on the ventricular level of the VSD changes along with the respiration phase, proving that the respiratory intrathoracic pressure change might be one of the reasons that causes the variation of the shunt velocity. This study provided more evidence for the new hypothesis of the mechanism of respiration effects on cardiac function.