Estimation of regional left ventricular wall stresses in intact canine hearts
Estimation of regional left ventricular wall stresses in intact canine hearts
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DOI：
10.1152/ajpheart.1998.275.5.h1879
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发表时间：
1998-11-01
影响因子：
4.8
通讯作者：
Miller, DC
中科院分区：
文献类型：
--
作者：
DeAnda, A;Komeda, M;Miller, DC
左心室（LV）壁应力是评估LV收缩功能的重要因素;然而，尚未开发出可重复的技术来确定瞬时局部或区域壁应力。14只犬接受了26个心肌标记物置入心室和间隔。一周后，在清醒、镇静、心房起搏基线条件下和强心剂刺激（钙）后，使用高速双平面视频荧光透视获得标记图像。模型考虑了左心室压力、局部室壁厚度、局部曲率半径和周向曲率半径，我们计算了9个左心室部位的平均室壁中应力。区域收缩末期和最大左室壁应力是不均匀的，并依赖于纬度（从心尖到基底增加，P < 0.001）和特定的壁（前壁>侧壁和后壁应力; P = 0.002）。多变量方差分析仅显示钙输注后左心室应力增加的趋势（P = 0.056）;随后的单变量分析分离出收缩末期左心室壁应力显著增加，除赤道区外，所有部位的变力状态均增加。本分析中使用的模型结合了局部几何因素，并提供了与既往研究相比的局部LV壁应力的合理估计。左心室壁应力是不均匀的，取决于特定的左心室部位。室壁应力的变化可能是由解剖学差异和/或LV部位之间的外在相互作用引起的，即，乳头肌和室间隔的影响。
Left ventricular (LV) wall stress is an important element in the assessment of LV systolic function; however, a reproducible technique to determine instantaneous local or regional wall stress has not been developed. Fourteen dogs underwent placement of twenty-six myocardial markers into the ventricle and septum. One week later, marker images were obtained using high-speed biplane videofluoroscopy under awake, sedated, atrially paced baseline conditions and after inotropic stimulation (calcium). With a model taking into account LV pressure, regional wall thickness, and meridional and circumferential regional radii of curvature, we computed average midwall stress for each of nine LV sites. Regional end-systolic and maximal LV wall stress were heterogeneous and dependent on latitude (increasing from apex to base, P < 0.001) and specific wall (anterior > lateral and posterior wall stresses; P = 0.002). Multivariate ANOVA demonstrated only a trend (P = 0.056) toward increased LV stress after calcium infusion; subsequent univariate analysis isolated significant increases in end-systolic LV wall stress with increased inotropic state at all sites except the equatorial regions. The model used in this analysis incorporates local geometric factors and provides a reasonable estimate of regional LV wall stress compared with previous studies. LV wall stress is heterogeneous and dependent on the particular LV site of interest. Variation in wall stress may be caused by anatomic differences and/or extrinsic interactions between LV sites, i.e., influences of the papillary muscles and the interventricular septum.