Measurement and Analysis of Structure and Function of Myocardium in Embryonic and Adult Heart

Citation

Nasiraei Moghaddam, Abbas (2007) Measurement and Analysis of Structure and Function of Myocardium in Embryonic and Adult Heart. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/RQE4-MA23. https://resolver.caltech.edu/CaltechETD:etd-06012007-143736

Abstract

Congestive heart failure is the most common and costly medical problem in the modern world. Current disease management procedures are mostly limited to treating the symptoms of this disease. The effective treatment, however, needs a deep understanding of the normal structure-function relationships of the myocardium.

The research of this study is concerned with the relationship between the structure and function of the myocardium in both embryonic and adult hearts. This relationship was investigated through an in-depth analysis of the spatial distribution of the local contractile function in the myocardium. The analysis is based on the heart kinematics captured through the tissue tracking of the myocardium.

Advanced imaging techniques, such as DENSE MRI and confocal microscopy, were used for tissue tracking in adult and embryonic myocardium, respectively. The acquired data, together with continuum mechanics concepts and computational methods, were exploited in a Lagrangian framework to measure appropriate characteristic parameters that describe local contribution of the myocardium in its global functionality.

This method resulted in novel understandings of the local and global functions in each of these hearts. In particular, it was observed in the adult heart that the left ventricle functionality is not uniformly distributed. Instead, the regions with higher effect on the pumping process form a helical band which wraps around the heart. This is the first time that such a myocardium macro-structure, which is supported by the established histological evidence, is revealed from its function in a beating heart. It can be considered as a landmark in connecting the structure and function of the heart through imaging. Furthermore, the compatibility of this model with microscopic observations about the fiber direction is investigated.

A similar approach was applied to embryonic zebrafish heart with GFP labeled myocytes. It identified distribution of regions that play an active role in functionality of the heart tube. This new understanding has provided better insights into the pumping mechanism of the embryonic heart.

Thesis Files