Schieken R M, Patel M R, Falsetti H L, Barnes R W, Lauer R M
Br Heart J. 1978 Sep;40(9):958-63. doi: 10.1136/hrt.40.9.958.
The first derivative thoracic impedance cardiogram, phonocardiogram, and electrocardiogram were recorded in three groups of 22 subjects each. In Group 1 (control), simultaneous impedance cardiogram, phonocardiogram, and aortic valve echocardiograms showed that the X point of the impedance cardiogram occurred synchronously with the aortic second heart sound and with echocardiographic aortic valve closure. In group 2 (clinical diagnosis of aortic regurgitation) the scalar magnitude of the impedance cardiogram O wave and the ratios of the impedance cardiogram wave form X/dz/dtmax and O/dz/dtmax were different from control. In addition, the early diastolic (X) and systolic portions (S) of the impedance cardiogram wave form of group 3 patients were planimetered and expressed as the ratio X/S, called the impedance cardiographic aortic regurgitant fraction (aortic RFI). The aortic RFI was increased by handgrip, a manoeuvre which acutely increases the magnitude of aortic regurgitation. The difference between Fick cardiac output and left ventricular angiographic output was used to calculate aortic valvular regurgitant fraction, which related closely to the impedance cardiogram. These data suggest that it is useful in the noninvasive assessment of aortic regurgitation.
对三组每组22名受试者记录了一阶导数胸阻抗心动图、心音图和心电图。在第1组（对照组）中，同步的阻抗心动图、心音图和主动脉瓣超声心动图显示，阻抗心动图的X点与主动脉第二心音以及超声心动图的主动脉瓣关闭同步出现。在第2组（主动脉反流临床诊断组）中，阻抗心动图O波的标量大小以及阻抗心动图波形X/dz/dtmax和O/dz/dtmax的比值与对照组不同。此外，对第3组患者阻抗心动图波形的舒张早期（X）和收缩期部分（S）进行求积，并表示为X/S比值，称为阻抗心动图主动脉反流分数（主动脉RFI）。通过握力动作可使主动脉RFI增加，握力动作会急性增加主动脉反流的程度。用Fick心输出量与左心室血管造影输出量之间的差值来计算主动脉瓣反流分数，其与阻抗心动图密切相关。这些数据表明，它在主动脉反流的无创评估中是有用的。
