Drott C, Lundholm K
Department of Surgery, Sahlgrens Hospital, University of Göteborg, Sweden.
Int J Obes Relat Metab Disord. 1992 Jul;16(7):481-6.
The heart is not spared from the catabolic effects of undernutrition, but is subject to the same degree of weight loss as skeletal muscle. Pumping performance, however, is not reduced in proportion to myocardial wasting and thus functional protection prevents failure of the hypotrophic heart. In animal experiments, no major qualitative changes in myocardial composition apart from reduced myosin ATPase activity have been found. This reduction in ATPase activity might be associated with down-regulation of thyroid hormones and the development of insulin resistance and serve as an energy saving adaptation. Increased cardiac sensitivity to adrenergic stimulation may also constitute a means to increase heart performance in situations with augmented circulatory demands. On the other hand, increased sensitivity and maximum response to adrenergic stimulation might render the heart more susceptible to arrhythmia, and thus explain sudden unexpected death following rapid weight loss.
心脏也无法免受营养不良的分解代谢影响，但其体重减轻程度与骨骼肌相同。然而，心脏泵血功能并不随心肌萎缩而按比例降低，因此功能性保护可防止心脏功能不全。在动物实验中，除了肌球蛋白ATP酶活性降低外，未发现心肌成分有重大质性变化。ATP酶活性的降低可能与甲状腺激素下调以及胰岛素抵抗的发展有关，并作为一种节能适应机制。心脏对肾上腺素能刺激的敏感性增加也可能是在循环需求增加的情况下提高心脏功能的一种方式。另一方面，对肾上腺素能刺激的敏感性和最大反应增加可能使心脏更容易发生心律失常，从而解释快速减重后突然意外死亡的原因。
