O'Toole J D, Reddy S P, Curtiss E I, Griff F W, Shaver J A
Circulation. 1976 May;53(5):752-8. doi: 10.1161/01.cir.53.5.752.
The sound-pressure correlates of the second high frequency component of a split first heart sound (S1) were investigated in 27 patients. An external phonocardiogram was recorded with high fidelity sound and pressure from the left and right atria in 21 patients, from the pulmonary artery in 14 of these, and from the central aorta in 11. In the remaining six patients, high fidelity recordings from the central aorta and right-sided chambers were obtained with an external phonocardiogram. The external component of S1 that coincided with a left atrial C wave and "internal sound" was defined as M1. In those cases where the left atrial pressure was not recorded, this component could be identified by a low frequency transient in the central aortic pressure trace. The other external high frequency component of S1 that was synchronous with a separate right atrial C wave and "internal sound" was defined as T1; with two exceptions, M1 preceded T1. The two exceptions which caused reversal of this order, so that T1 preceded M1, were due to chronic left bundle branch block and mitral stenosis. In both cases, T1 was shown to be distinctly separated from the upstroke of pressure rise in the central aorta. This finding was also demonstrated in three cases of right bundle branch block and one case with aortic valvular disease. The usual asynchrony of ventricular contraction was altered by induction of ventricular premature systoles; the separation of externally identifiable M1 and T1 components and their internal markers was predictably altered by this maneuver. The occurrence of T1 was variable in relation to the upstroke of the pulmonary artery pressure, which suggests that it is not related to pulmonic ejection. It is concluded that micromanometrically recorded right and left atrial C waves can serve as markers for externally recordable M1 and T1 components of the first heart sound. In addition, T1 is frequently an externally recordable and audible event.
对27例患者分裂第一心音（S1）的第二个高频成分的声压相关性进行了研究。用高保真声音和压力记录了21例患者左、右心房的体外心音图，其中14例记录了肺动脉的情况，11例记录了主动脉中心的情况。其余6例患者通过体外心音图获得了主动脉中心和右侧心腔的高保真记录。与左心房C波和“内心音”同时出现的S1外部成分被定义为M1。在未记录左心房压力的情况下，该成分可通过主动脉中心压力曲线上的低频瞬变来识别。S1的另一个外部高频成分与单独的右心房C波和“内心音”同步，被定义为T1；除两例外，M1先于T1。导致这种顺序颠倒（即T1先于M1）的两个例外情况是慢性左束支传导阻滞和二尖瓣狭窄。在这两种情况下，T1均显示与主动脉中心压力上升的起始明显分离。在3例右束支传导阻滞和1例主动脉瓣疾病患者中也证实了这一发现。室性早搏的诱发改变了心室收缩通常的不同步性；这种操作可预测地改变了外部可识别的M1和T1成分及其内部标记物的分离。T1的出现与肺动脉压力上升的起始有关，这表明它与肺动脉射血无关。结论是，通过微测压记录的左右心房C波可作为第一心音外部可记录的M1和T1成分的标记物。此外，T1通常是一个外部可记录和可听到的事件。
