临床上以往按患者能胜任多少体力活动而将心脏功能分为四级,这种分类分法往往带有较大的主观成份,很难得到客观的、一致的评定结果。katz等早在1923年就已开始测定心脏收缩时间间期(STI),但临床用来作为心泵功能评定指标还是近十余年的事,主要是由于当时的STI测定不能与直接的心功能检查作对比,所以不能肯定其实用价值及临床 In the past, according to how many physical activities a patient can perform and the heart function is divided into four levels, this classification is often subjective with a larger subjective component, it is difficult to get objective and consistent assessment results. Katz and other early as early as 1923 began to measure the systolic time interval (STI), but the clinical assessment of cardiac function as a marker or nearly a decade of events, mainly because the STI measurement was not directly associated with cardiac function Check for comparison, it can not be sure its practical value and clinical