MODEL SELECTION FOR VENTRICULAR MECHANICS - A SENSITIVITY ANALYSIS APPROACH
MODEL SELECTION FOR VENTRICULAR MECHANICS - A SENSITIVITY ANALYSIS APPROACH
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DOI：
10.1016/0141-5425(87)90094-x
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发表时间：
1987-01-01
期刊：
影响因子：
--
通讯作者：
AVANZOLINI, G
中科院分区：
文献类型：
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作者：
CAPPELLO, A;CEVENINI, G;AVANZOLINI, G
左心室泵特性的定量表征对于生理和临床目的都具有重要意义。为此，过去已经提出了几种描述，其中心室被视为耦合到内部阻抗的等容压力发生器，内部阻抗被认为是仅粘性的、仅弹性的或粘弹性的。虽然这些模型已被广泛使用，但各自的优点和局限性尚未得到充分阐明。在本文中，六个模型的左心室泵功能，粘弹性类型，比较使用模拟和实验数据中的一个典型的参数估计方法。弹性和粘性参数估计开始从心室压力和主动脉流量，以及在相同的前负荷的等容压力。比较的基础是与从收集的数据和参数估计值的协方差矩阵获得的拟合相关的公认标准。后者允许在参数空间中评估所谓的无差异区域，如果存在弹性和粘性元素，则由椭圆表示。无差异区域的属性由与椭圆的面积和偏心率相关的两个指标综合表示：第一个指标表示参数估计的平均准确度，第二个指标提供有关单个参数变化的不同敏感度的信息。在模拟和实验情况下，这种比较通常会导致首选弹性和粘度随时间变化与等容发展的心室压成线性比例的模型。弹性效应的适当描述揭示了它是非常关键的，而粘性效应虽然改善了数据的拟合，但不那么关键。
Quantitative characterization of left ventricle pump properties has been recognized as being of great significance for both physiological and clinical purposes. Several descriptions have been proposed in the past to this end, where the ventricle is viewed as an isovolumic pressure generator coupled to an internal impedance, considered as either only viscous, only elastic or viscoelastic. Though these models have been used widely, the respective advantages and limits have not been fully elucidated. In this paper, six models for the left ventricular pumping function, of the viscoelastic type, are compared using both simulated and experimental data in a typical parameter estimation approach. Elastic and viscous parameters are estimated starting from ventricular pressure and aortic flow, together with the isovolumic pressure at the same preload. The basis for the comparison is the well-established criterion relating to fit obtained from collected data and the covariance matrix of the parameter estimates. The latter allows evaluation of the so-called indifference region in the parameter space, which is represented by an ellipse if both elastic and viscous elements are present. The properties of the indifference region are synthetically represented by two indices linked to the area and the eccentricity of the ellipse: the first represents the mean accuracy of the parameter estimate, the second gives information about the different sensitivities to variation of single parameters. This comparison, in both simulated and experimental cases, generally leads to preference for a model where elastance and viscosity vary with time in linear proportion to the isovolumically developed ventricular pressure. Appropriate description of the elastic effect reveals it to be very crucial while the viscous effect, though improving the fitting of data, is less critical.