Production and abolition of alternation in mechanical action of the ventricle.
Production and abolition of alternation in mechanical action of the ventricle.
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心室机械动作交替的产生和废除。
DOI：
10.1152/ajplegacy.1965.209.5.945
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发表时间：
1965
期刊：
影响因子：
--
通讯作者：
C. Brooks
中科院分区：
文献类型：
--
作者：
J. Gilbert;M. Janse;H. Lu;J. Pinkston;C. Brooks
当心脏被驱动超过一定的速度时，心室机械反应的持续交替，即脉冲交替。这个临界速率是不同的，但往往发生在200到300次/分钟之间。通过心房电极，直接驱动心室的速度比间接驱动略快（10-20次/分钟），而不会出现脉冲交替。对于持续交替有一个比率“阈值”，它表示补偿的比率限制。交替出现的频率较低，但收缩过程可以逐渐加速，甚至在去神经心脏和肾上腺切除术后交替消失。较慢的渐进式加速延迟了脉冲交替的发生，并且补偿比逐步速率变化发生得更快。超过脉冲交替阈值的快速驱动可以产生一些额外的收缩-松弛过程的加速：如果速率降低到先前产生持续交替的水平，脉冲交替在几秒钟内不会发生。讨论了这些现象与“收缩后增强”和“收缩后增强”的相似之处以及与儿茶酚胺释放和作用有关的含义。
Persisting alternation in mechanical response of the ventricle, pulsus alternans, develops when the heart is driven above certain rates. This critical rate varies, but tends to occur between rates of 200 and 300 beats/min. The ventricle can be driven slightly faster (10–20 beats/min) by direct than by indirect drive, through atrial electrodes, without showing pulsus alternans. There is a rate "threshold" for persisting alternation which represents the rate limits of compensation. Alternation appears at lower rates but the contractile process can gradually accelerate and alternation disappears even in denervated hearts and after adrenalectomy. Slower progressive accelerations delay onset of pulsus alternans and compensation occurs more quickly than when stepwise rate changes are made. Fast drives above the threshold for pulsus alternans can produce some additional acceleration of the contraction-relaxation process: if the rate is reduced to a level which previously produced a persisting alternation, pulsus alternans does not occur for a number of seconds. The resemblances of these phenomena to "treppe" and "postextrasystolic potentiation" and implications relative to catecholamine release and action are discussed.