权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Evaluation of Cardiac Contractility by means of Q-D and D-S Time Intervals

通过 Q-D 和 D-S 时间间隔评估心脏收缩力

基本信息

批准号：
12671496
负责人：
TANAKA Yoshifumi
金额：
$ 0.32万
依托单位：
Kyoto Prefectural University of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Q-D time is the time interval between the beginning of electrical Q wave in ECG and the period of diastolic pressure. It is regarded as the time lag of electrical action and mechanical action of the heart muscle. D-S time is the time interval between the period of the diastolic pressure and that of the systolic pressure. We measured both time intervals in patients undergoing the cardiac surgery.In the normal cardiac condition, Q-D time and D-S time was almost 100 m second and these time intervals did not affected by the heart rate. When the patient was under the extra corporeal cardiac perfusion (ECC) with hypothermia, these time intervals extended two or three times significantly. Changes of D-S time was more significant compared with that of Q-D time.Physical power of cardiac muscle is evaluated by multiplied value of force and duration time. Therefore the more the contractility of the heart muscle decreases, the more the duration time is needed for the ejection of the same amount of blood in the left ventricle. The cardiac work during Q-D time is regarded an accumulating the potential energy from the level of atrial pressure to that of diastolic pressure. There is no external work to the systemic circulation during Q-D time. D-S time is, however, obviously the loading time interval of the cardiac function. The stroke volume is ejected and the systemic blood pressure is increased from diastole to systole. Hence, we conclude that the load of cardiac muscle during the D-S time is heavier than that of during Q-D time.

Q-D时间是心电图Q波开始与舒张压周期之间的时间间隔。它被认为是心肌的电作用和机械作用的时间滞后。D-S时间是舒张压周期与收缩压周期之间的时间间隔。我们测量了心脏手术病人的Q-D时间和D-S时间，在心脏正常情况下，Q-D时间和D-S时间约为100毫秒，且不受心率的影响。当病人在体外循环心脏灌注（ECC）和低温时，这些时间间隔明显延长了两到三倍。D-S时间的变化较Q-D时间的变化更为显著，心肌的体力可用力与持续时间的乘积来评价。因此，心肌的收缩性降低得越多，左心室中喷射相同量的血液所需的持续时间就越长。Q-D时间内的心脏作功被认为是从心房压水平到舒张压水平的势能的积累。在Q-D时间内，体循环没有外部功。然而，D-S时间显然是心脏功能的负荷时间间隔。每搏输出量被排出，全身血压从舒张期增加到收缩期。因此，我们认为D-S时间的心肌负荷大于Q-D时间的心肌负荷。