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J Biomech Eng. 2009 Nov;131(11):111001. doi: 10.1115/1.3148464.

A computationally efficient formal optimization of regional myocardial contractility in a sheep with left ventricular aneurysm.

Author information

1
Department of Surgery, University of California, San Francisco, USA.

Abstract

A non-invasive method for estimating regional myocardial contractility in vivo would be of great value in the design and evaluation of new surgical and medical strategies to treat and/or prevent infarction-induced heart failure. As a first step towards developing such a method, an explicit finite element (FE) model-based formal optimization of regional myocardial contractility in a sheep with left ventricular (LV) aneurysm was performed using tagged magnetic resonance (MR) images and cardiac catheterization pressures. From the tagged MR images, 3-dimensional (3D) myocardial strains, LV volumes and geometry for the animal-specific 3D FE model of the LV were calculated, while the LV pressures provided physiological loading conditions. Active material parameters (T(max_B) and T(max_R)) in the non-infarcted myocardium adjacent to the aneurysm (borderzone) and in myocardium remote from the aneurysm were estimated by minimizing the errors between FE model-predicted and measured systolic strains and LV volumes using the successive response surface method for optimization. The significant depression in optimized T(max_B) relative to T(max_R) was confirmed by direct ex vivo force measurements from skinned fiber preparations. The optimized values of T(max_B) and T(max_R) were not overly sensitive to the passive material parameters specified. The computation time of less than 5 hours associated with our proposed method for estimating regional myocardial contractility in vivo makes it a potentially very useful clinical tool.

KEYWORDS:

cardiac mechanics; finite element modeling; numerical optimization; tagged magnetic resonance imaging

PMID:
20016753
PMCID:
PMC2793686
DOI:
10.1115/1.3148464
[Indexed for MEDLINE]
Free PMC Article

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