An experimental and theoretical model for the passive biomechanical properties of the intact heart. (Volumes I and II).

摘要

The study of diastolic function of the heart has proven to have great clinical relevance. A strategy is proposed whereby the biomechanical properties of the heart in diastole may be quantified, thus providing a clinical tool towards improved understanding, diagnosis, and management of cardiac disease.;Previous attempts to model the biomechanics of the heart have either imposed restrictive simplifications on geometry or have ignored the inherent complexities of the material. State-of-the-art nuclear magnetic resonance has now made it possible to image the beating heart in extraordinary detail. To date, the power of this technology has not yet been exploited towards modeling the biomechanics of the heart. The present work has employed this technology in characterizing the motion of the intact heart.;The present research initiates a systematic formulation of a theoretical model based on first principles of continuum mechanics. To this end, constitutive equations describing the orthotropic, compressible, nonlinear elastic properties of myocardium have been presented, and will serve as a sound first approximation. The solution of the mathematical problem described herein will provide an excellent basis upon which more comprehensive models may be built.;Because the present work does not propose to make any simplifying assumptions regarding the geometry of the heart, a numerical scheme will ultimately be required to solve the governing equations. With this in mind, the research has developed experimental techniques for acquiring the appropriate intact cardiac data and performing the required pre-processing thereof so that such a solution may be borne out by subsequent research.