Luisada A A, Coleman B, Wallick D, Bhat P K
Jpn Heart J. 1977 Jan;18(1):81-91. doi: 10.1536/ihj.18.81.
Studies are reported on the exact timing of the aortic component of the second sound in relationship to aortic pressure and flow velocity, and also to aortic valve closure. These studies were performed in animals by means of catheter-tip probes and an electric contact introduced into the aortic valve. They were supplemented by echocardiographic stuides of the aortic valve, and impedance cardiograms in man. Opening of the aortic valve and its relationship to the first heart sound were also studied. It was observed that the second component of the first heart sound grossly coincides with the opening of the aortic valve. The aortic component of the second sound starts a few milliseconds after aortic valve closure. It starts after the incisura of the aortic pressure tracing and the drop of the velocity curve to the zero line; it then increases attaining its maximum at the peak of the rapid rebound of the aortic pressure, which coincides with the trough of the velocity tracing. The final interpretation on the mechanism of the second sound agrees in principle with the studies of Luciani, Wiggers, and Rushmer attributing the sound vibrations to release of the energy stored in the aortic wall, which accelerates the flow and causes deceleration of numerous structures (aortic and valvar) as well as of the blood. Studies of the rate of change of acceleration of pressure confirm this interpretation.
报告了关于第二心音主动脉成分相对于主动脉压力、流速以及主动脉瓣关闭的确切时间的研究。这些研究是通过导管尖端探头和插入主动脉瓣的电触点在动物身上进行的。通过对主动脉瓣的超声心动图研究以及人体的阻抗心动图对这些研究进行了补充。还研究了主动脉瓣的开放及其与第一心音的关系。观察到第一心音的第二成分与主动脉瓣开放大致同时出现。第二心音的主动脉成分在主动脉瓣关闭后几毫秒开始。它在主动脉压力曲线的切迹和速度曲线降至零线之后开始；然后增加，在主动脉压力快速反弹的峰值处达到最大值，这与速度曲线的波谷一致。关于第二心音机制的最终解释在原则上与卢西亚尼、威格斯和拉什默的研究一致，即将声音振动归因于主动脉壁中储存能量的释放，这加速了血流并导致许多结构（主动脉和瓣膜）以及血液减速。压力加速度变化率的研究证实了这一解释。
