The effects of load on cardiac function

Lee, Eveline 2018. The effects of load on cardiac function. MD Thesis, Cardiff University. Item availability restricted.

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Abstract

Heart failure is a common and debilitating disease. In recent years, improved diagnosis and treatment have resulted in more people than ever living with the condition. Accurate quantification of cardiac function is essential in the diagnosis and monitoring of heart failure. A good diagnostic test must reflect cardiac contractile state and is insensitive to physiological changes in load. This thesis investigated the effects of changing load on existing and novel indices of cardiac function obtained using echocardiography. Firstly, breathless patients on maintenance haemodialysis underwent echocardiography immediately before and after a session of dialysis (large preload change). Secondly, healthy blood donors underwent echocardiography immediately before and after a session of venesection (moderate preload change). Indices of cardiac function showed differential preload sensitivity during the above experiments. Conventional indices (EF, MAPSE) were relatively preload resistant. Longitudinal and radial tissue Doppler velocities and left ventricular apical rotation were more load-sensitive and tracked moderate preload change. Mid left ventricular circumferential strain was resistant to moderate preload change but was sensitive to a large preload change. Mid left ventricular radial strain, basal rotation and longitudinal strain and strain rate were unaffected by these changes in preload. The key result from this thesis is that many echocardiographic indices of cardiac function are sensitive to changes in preload. Therefore, clinical interpretation of these results must take into account the loading status at the time of study.

Item Type:	Thesis (MD)
Status:	Unpublished
Schools:	Medicine
Date of First Compliant Deposit:	23 September 2019
Last Modified:	23 Jul 2020 02:13
URI:	https://orca.cardiff.ac.uk/id/eprint/125582

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