Cycle length dependence of the electrophysiological effects of increased load on the myocardium.
Cycle length dependence of the electrophysiological effects of increased load on the myocardium.
复制标题
心肌负荷增加的电生理效应的周期长度依赖性。
DOI：
10.1161/01.cir.94.5.1131
复制
发表时间：
1996
期刊：
影响因子：
37.8
通讯作者：
M. Lab
中科院分区：
文献类型：
--
作者：
S. Horner;D. J. Dick;C. Murphy;M. Lab
背景
机械电反馈是机械活动改变心肌电生理的过程，已被认为与心律失常的发生有关。我们通过测量稳态动作电位持续时间的变化，更具体地说，测量瞬间施加的负荷变化时的电恢复，来研究可能的心律失常发生机制，因为动作电位的恢复可能为心律失常的发生提供线索。
方法和结果
麻醉猪，暴露它们的心脏。在主动脉周围放置陷阱，并对右心房进行起搏。记录左心室的室压、单相动作电位和节段运动。在一过性主动脉阻断前和阻断期间测量动作电位时程。根据正常负荷或一过性主动脉阻断期间的记录构建电恢复曲线。主动脉阻断时动作电位时程缩短的程度随着稳态每搏间期的减少而减少(P=.0008)。对照恢复曲线具有典型的构型，最初快速上升，通常是单调的，向平台期上升。一些曲线显示出边缘的“超常”截面。负荷增加使恢复曲线平台期动作电位时程缩短(9.4ms，P=0.0001)，恢复曲线起始点动作电位时程延长(8.7ms，P=0.03)。增加负荷使电恢复曲线的最大斜率增加32ms/100ms(P=0.04)。负荷的增加也增加了电恢复曲线的超常周期。
结论
力电反馈使心率相关的电生理学发生改变，这可能有利于形成有利于心律失常发生的基质。
BACKGROUND
Mechanoelectric feedback, the process by which changes in mechanical activity change the electrophysiology of the myocardium, has been linked to the genesis of arrhythmias. We investigated possible arrhythmogenic mechanisms by measuring changes in steady-state action potential duration and, more particularly, electrical restitution on a transiently applied load change, because action potential recovery may provide clues to arrhythmogenesis.
METHODS AND RESULTS
Pigs were anesthetized and their hearts exposed. A snare was placed around the aorta, and the right atrium was paced. Ventricular pressure, monophasic action potential, and segment motion were recorded from the left ventricle. The action potential duration was measured before and during transient aortic occlusion. Electrical restitution curves were constructed from the records obtained during normal loading or during transient aortic occlusion. The degree of shortening of action potential duration on aortic occlusion decreased with decreases in the steady-state beat-to-beat interval (P = .0008). Control restitution curves had the typical configuration, with a rapid initial, usually monotonic, rise toward a plateau. Some curves showed a marginal "supernormal" section. Increased load reduced the action potential duration at the plateau of the restitution curve (9.4 ms, P < .0001) but increased the action potential duration at the start of the restitution curve (8.7 ms, P = .03). Increased loading increased the maximum slope of the electrical restitution curve by 32 ms/100 ms (P = .04). Increased load also increased the supernormal period of the electrical restitution curves.
CONCLUSIONS
Mechanoelectric feedback produces changes in rate-dependent electrophysiology, which could favor a matrix conducive to arrhythmogenesis.
影响因子：
37.8
作者：
HANSEN, DE;CRAIG, CS;HONDEGHEM, LM
通讯作者：
HONDEGHEM, LM
影响因子：
10.8
作者：
FRANZ, MR;BURKHOFF, D;SAGAWA, K
通讯作者：
SAGAWA, K
大鼠对高胰岛素血症的区域交感神经反应不均匀。
DOI：
10.1152/ajpregu.1993.264.2.r423
发表时间：
1993
期刊：
The American journal of physiology
影响因子：
--
作者：
Morgan,DA;Balon,TW;Ginsberg,BH;Mark,AL
通讯作者：
Mark,AL