Left ventricular restoring forces: modulation by heart rate and contractility.
Left ventricular restoring forces: modulation by heart rate and contractility.
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左心室恢复力：心率和收缩力的调节。
DOI：
10.1007/s003950050242
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发表时间：
1998
影响因子：
9.5
通讯作者：
Bell,SP
中科院分区：
文献类型：
--
作者：
LeWinter,MM;Fabian,J;Bell,SP
我们在开胸犬中使用了一种双腔起搏系统，以快速夹闭左心房压力低于左心室（LV）舒张压，以产生非充盈性舒张压，在此期间，LV在其收缩末期容积（ESV）完全放松。当完全松弛压力（FRP）为负时，认为收缩期间产生的恢复力（RF）导致LV通过抽吸充盈。我们根据完全放松的压力-容积关系（FRPV关系，FRP与ESV作图）表征了RF，该关系具有负和正部分以及平衡容积（FRP = 0 mmHg）。负FRP通常出现在生理充盈范围的下半部分。收缩力增加（全身性多巴酚丁胺）使FRPV关系向下移动，表明任何ESV的RF更大。经冠状动脉左前降支冠状动脉内注射多巴酚丁胺具有相同的效果。心率从约100次/分急剧增加至150次/分并不改变FRPV关系。相比之下，慢性心动过速心力衰竭导致产生RF的能力显著降低，即使是在非常低的体积下。因此，RF通常有助于LV充盈。在上述范围内，整体和前壁收缩力的急性增加而不是心率的急性增加会增强它们。慢性心动过速心力衰竭明显减弱RF。后者可能是心力衰竭舒张功能障碍的一种以前未被认识的机制。
We used a servomotor system in open-chest dogs to rapidly clamp left atrial pressure below left ventricular (LV) diastolic pressure in order to produce nonfilling diastoles during which the LV fully relaxed at its end-systolic volume (ESV). Restoring forces (RFs) generated during contraction which result in LV filling by suction were considered to be present when the fully relaxed pressure (FRP) was negative. We characterized RFs in terms of the fully relaxed pressure-volume relation (FRPV relation, FRP plotted vs ESV), which has negative and positive portions and an equilibrium volume (FRP = 0 mmHg). A negative FRP is ordinarily present over the lower half of the physiologic filling range. Increased contractility (systemic dobutamine) shifts the FRPV relation downward, indicating greater RFs at any ESV. Intracoronary dobutamine administered via the left anterior descending coronary artery has the same effect. Acute increases in heart rate from about 100 to 150 beats/min did not alter the FRPV relation. In contrast, chronic tachycardia heart failure resulted in marked depression of the ability to generate RFs, even at very low volumes. Thus, RFs normally contribute to LV filling. They are augmented by acute increases in global and anterior wall contractility but not heart rate, within the range specified above. Chronic tachycardia heart failure markedly attenuated RFs. The latter may constitute a previously unappreciated mechanism of diastolic dysfunction in heart failure.