Novel parameters for assessing cardiac dyssynchrony

Jones, Kirsty Anne (2021) Novel parameters for assessing cardiac dyssynchrony. PhD thesis, University of Glasgow.

Abstract

Cardiac mechanical dyssynchrony describes the variation in the timing of contraction or relaxation within the ventricle and can be assessed using various imaging techniques. Electrical dyssynchrony has previously been used as a surrogate for mechanical dyssynchrony. However, it is now widely recognised that mechanical dyssynchrony can occur without the presence of electrical dyssynchrony. Therefore, it has become increasingly important to develop quantitative measures of mechanical dyssynchrony. Although echocardiography has led in this area, radionuclide ventriculography (RNVG) imaging can also be used.

This research aims to investigate the use of novel phase parameters from RNVG, including synchrony, entropy, phase standard deviation, approximate entropy, and sample entropy, to provide a quantitative measure of cardiac dyssynchrony. There is limited published data applying these parameters to phase images, and there is currently no established normal range. To achieve these aims, each parameter has been optimised and tested on both simulated and clinical data. In addition, the optimised parameters have been applied to clinical data sets to assess the ability to predict patient outcome.

The results highlight the importance of optimising input parameters for approximate entropy and sample entropy and demonstrate that the selected values are appropriate for application to RNVG phase images. The clinical results using the optimised parameters are promising for assessing patients prior to receiving cardiotoxic cancer therapy. Approximate entropy combined with left ventricular ejection fraction was able to predict those at a higher risk of cardiac dysfunction before treatment commenced. The dyssynchrony parameters were also used to assess a group of patients with heart failure with reduced ejection fraction. The results demonstrated that dyssynchrony, left ventricular ejection fraction, and right ventricular ejection fraction improved after beta-blocker. In addition, patients with non-ischaemic heart failure and dyssynchronous left ventricular contraction were more likely to respond to beta-blocker therapy.

This research has successfully investigated novel dyssynchrony parameters for radionuclide ventriculography imaging. Overall, this research strengthens the idea that dyssynchrony can predict patient outcomes and improve clinical decision making.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
• Supervisor's Name: Hamilton, Dr. David J., Paterson, Mr. Craig and Small, Dr. Alexander D.
• Date of Award: 2021
• Depositing User: Theses Team
• Unique ID: glathesis:2021-82588
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 07 Dec 2021 12:11
• Last Modified: 08 Apr 2022 17:08
• Thesis DOI: 10.5525/gla.thesis.82588
• URI: https://theses.gla.ac.uk/id/eprint/82588

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