第二心音(S_2)标志着心室的舒张期,从生理学上讲,心率正常或心率较慢的健康人,舒张期是心动周期中最长的间期,听诊上健康人的舒张期也是最寂静的,反映在心音图中,此间期内的曲线也是最平稳而光滑的。但在某些情况下,一些重要的血流动力学改变也常常发生在舒张期中,因此某些人可以在舒张期中从听诊上听到一下“额外音”,此额外音的声响和强度可因人而异,有时它与听诊的部位及被检者的体位有一定关系。从心音图上所录得 The second heart sound (S_2) marked ventricular diastolic, physiologically speaking, normal heart rate or slow heart rate of healthy people, diastolic heart cycle is the longest interval, auscultatory diastolic period is the most silent , Reflected in the heart sound chart, the curve during this period is the most stable and smooth. However, in some cases, some important hemodynamic changes often occur during diastole, so some people can hear an “extra sound” from the auscultation during diastole, the sound and intensity of this extra sound It varies from person to person, and sometimes it is related to the position of the auscultation and the position of the subject. Recorded from the heart sound map