在临床工作中,欲测定收缩时间间期(STI),如s Q—B、R—Z、B—X、总电机械收缩时间Q—S_2,射血前期(PEP)与左心室射血期(LVET)之比(相当于Q—B/B—X)以及心肌收缩力指数HI=(dz)/(dt)/R—z等,一般都需要多道记录仪同步描记心电、心音、阻抗微分图。为了充分利用广泛使用的单笔心电图机作描记,我们研究了一种叠加法,即根据物理学的电位叠加原理,设计合适的 In clinical work, to determine the systolic time interval (STI), such as s Q-B, R-Z, B-X, total electrical mechanical contraction time Q-S_2, pre-ejection (PEP) and left ventricular ejection period (LVET) ratio (equivalent Q-B / B-X) and myocardial contractility index HI = (dz) / (dt) / R-z, etc., generally require simultaneous multi-channel recorder ECG, heart sounds, Impedance differential graph. In order to make full use of the widely used single electrocardiogram for tracings, we studied a superposition method, which is based on the principle of physical superposition of potential, the design of suitable