Maximum heart rate does not limit cardiac output at rest or during exercise in the American alligator ( Alligator mississippiensis).
Maximum heart rate does not limit cardiac output at rest or during exercise in the American alligator ( Alligator mississippiensis).
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最大心率并不限制美洲短吻鳄（密西西比短吻鳄）在休息或运动时的心输出量。
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
D. Crossley
中科院分区：
文献类型：
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作者：
William Joyce;R. Elsey;Tobias Wang;D. Crossley
在大多数脊椎动物中，心输出量的增加是由于心率(Fh)的增加，而每搏量(Vs)变化很小或没有变化，最大心输出量(Q̇)通常达到或接近最大Fh。因此，我们检验了增加最大fh可能增加最大Q̇的假设。为此，我们研究了右房起搏抬高Fh对扬子鳄安静和游泳时Q-̇的影响。在正常游泳时，Q̇完全由于心动过速而增加(29 ± 1至40 ± 3次/分钟)，而Vs保持稳定。在静息和游动的扬子鳄中，随着右心房起搏增加fh会导致Vs的平行下降，从而导致心输出量不变。在游泳动物中，这种互易关系扩展到超生理Fh(高达~72次/分钟)，这表明最大Fh并不限制最大心输出量，Fh的变化次要于决定静息和运动时静脉回流的外周因素(例如血管电容)。
In most vertebrates, increases in cardiac output result from increases in heart rate (fH) with little or no change in stroke volume (Vs), and maximum cardiac output (Q̇) is typically attained at or close to maximum fH. We therefore tested the hypothesis that increasing maximum fH may increase maximum Q̇. To this end, we investigated the effects of elevating fH with right atrial pacing on Q̇ in the American alligator ( Alligator mississippiensis) at rest and while swimming. During normal swimming, Q̇ increased entirely by virtue of a tachycardia (29 ± 1 to 40 ± 3 beats/min), whereas Vs remained stable. In both resting and swimming alligators, increasing fH with right atrial pacing resulted in a parallel decline in Vs that resulted in an unchanged cardiac output. In swimming animals, this reciprocal relationship extended to supraphysiological fH (up to ~72 beats/min), which suggests that maximum fH does not limit maximum cardiac output and that fH changes are secondary to the peripheral factors (for example vascular capacitance) that determine venous return at rest and during exercise.
狗休息和动态运动时心脏充盈压对心输出量的依赖性。
DOI：
10.1152/ajpheart.1993.265.1.h316
发表时间：
1993
期刊：
The American journal of physiology
影响因子：
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作者：
Sheriff,DD;Zhou,XP;Scher,AM;Rowell,LB
通讯作者：
Rowell,LB