Sakamoto T, Ichiyasu H, Hayashi T, Kawaratani H, Amano K
Jpn Heart J. 1976 Mar;17(2):150-62. doi: 10.1536/ihj.17.150.
To clarify the genesis of the third heart sound (IIIS), phonoechocardiographic analysis was made in 31 cases with apparent IIIS. The mitral valve, either anterior or posterior, showed no definite movement coincided with the IIIS. At the time of IIIS, mitral valve is in the closing process, but it is still widely open, and there was no evidence of the stretch or tension of the valve apparatus. On the other hand, the endocardial echoes, either of interventricular septum or of posterior wall of the left ventricle, almost always showed definite check point (point of inflexion) during (or exactly at the end of) rapid ventricular filling as manifested by the sudden change in the diastolic dimension of the left ventricle near the apex. The IIIS seems likely to originate from the abruptly arrested momentum of the moving mass of blood at this check point and then the vibration of the relaxed cardiohemic system.
为阐明第三心音（S3）的产生机制，对31例有明显S3的患者进行了心音超声心动图分析。二尖瓣，无论是前叶还是后叶，均未显示与S3一致的明确运动。在S3出现时，二尖瓣处于关闭过程中，但仍广泛开放，且没有瓣膜装置伸展或紧张的证据。另一方面，室间隔或左心室后壁的心内膜回声，在快速心室充盈期间（或恰好在快速心室充盈结束时），几乎总是显示明确的转折点（拐点），表现为心尖附近左心室舒张期内径的突然变化。S3似乎很可能源于在此转折点处移动的血液团块突然停止的动量，然后是松弛的心血液循环系统的振动。
