收缩时间间期(systolic time intervals,STI)测定是无创性心机能测定方法之一。这个方法对人体无损伤,没有危险性,而且方法简单可靠,易于推广。STI主要测量左心室的作工,可以定量估价各种心脏病对左心室的影响,它最大的优点是可以多次检查,所以是麻醉和手术中一项很有意义的监测指标。 Systolic time intervals (STI) measurement is one of the noninvasive methods for determining cardiac function. This method of human damage, no danger, but the method is simple and reliable, easy to promote. STI mainly measures the work of the left ventricle, which can quantitatively evaluate the effects of various heart diseases on the left ventricle. Its biggest advantage is that it can be examined many times, so it is a very meaningful indicator of anesthesia and surgery.