ALTERATIONS IN LEFT-VENTRICULAR TWIST MECHANICS WITH INOTROPIC STIMULATION AND VOLUME LOADING IN HUMAN-SUBJECTS
ALTERATIONS IN LEFT-VENTRICULAR TWIST MECHANICS WITH INOTROPIC STIMULATION AND VOLUME LOADING IN HUMAN-SUBJECTS
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DOI：
10.1161/01.cir.89.1.142
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发表时间：
1994-01-01
期刊：
影响因子：
37.8
通讯作者：
MILLER, DC
中科院分区：
文献类型：
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作者：
MOON, MR;INGELS, NB;MILLER, DC
左心室扭转是左心室长轴的纵向旋转梯度，在收缩末期势能的储存和随后的舒张早期弹性回缩释放中起重要作用;但是，在此情况下，负荷和正性肌力状态对人类受试者左室收缩期扭转和舒张期解扭转的影响以前没有被表征。移植后1年，研究了植入12个不透射线的左室中壁心肌标记物的受体。在对照条件下和后负荷增强（甲氧胺，5 - 10 μ g.kg（-1）.min（-1））、正性肌力刺激（多巴酚丁胺，5 μ g. kg（-1）.min（-1））和前负荷增强（生理盐水容量负荷）后，记录双平面电影荧光标记图像和LV压力。通过收缩期最大扭转（T-max[rad/cm]）、峰值负扭转率（-dT/dt（min）[rad.cm（-1）.s（-1）]）和扭转归一化射血分数关系的斜率（T-nEFR，M（sys）[rad/cm]）评估收缩期扭转动力学。舒张期解旋通过峰值正解旋率（+dT/dt（max），[rad.cm（-1）.s（-1）]）和舒张早期（M（ear-dia））和舒张中期（M（mid-dia））T-nEFR的dope（rad/cm）来评估。与对照值相比，LV压力和容量负荷对T-max、-dT/dt（min）或M（sys）无显著影响;然而，变力性刺激显著增加了描述收缩期扭转的所有参数（T-max：-0.10+/-0.03 vs-0.06+/-0.02 rad/cm，P
Background Left ventricular (LV) twist, the longitudinal gradient of circumferential rotation about the LV long axis, may play an important role in the storage of potential energy at end systole and its subsequent release as elastic recoil during early diastole; however, the effects of load and inotropic state on LV systolic twist and diastolic untwist in human subjects have not previously been characterized.Methods and Results Six cardiac transplant recipients with 12 implanted radiopaque midwall LV myocardial markers were studied 1 year after transplantation. Biplane cinefluoroscopic marker images and LV pressure were recorded during control conditions and after afterload augmentation (methoxamine, 5 to 10 mu g.kg(-1).min(-1)), inotropic stimulation (dobutamine, 5 mu g.kg(-1).min(-1)), and preload augmentation (volume loading with normal saline). Systolic twist dynamics were assessed by maximum twist (T-max[rad/cm]), peak negative twist rate (-dT/dt(min)[rad.cm(-1).s(-1)]), and the slope of the twist normalized-ejection fraction relation (T-nEFR, M(sys)[rad/cm]) during systole. Diastolic untwist was assessed by the peak positive untwist rate (+dT/dt(max), [rad.cm(-1).s(-1)]) and the dopes (rad/cm) of the T-nEFR during early diastole (M(ear-dia)) and mid diastole (M(mid-dia)). Compared with control values, LV pressure and volume loading had no significant effect on T-max, -dT/dt(min), or M(sys); however, inotropic stimulation significantly increased all parameters describing systolic twist (T-max: -0.10+/-0.03 versus -0.06+/-0.02 rad/cm, P