Measurement of diastolic left ventricular (LV) function is vitally important in the
assessment of cardiac disease. However, only limited information on tissue function can be
obtained with current clinical techniques. This Thesis developed and investigated novel
parameters of both global and regional myocardial function, using cardiac magnetic resonance
imaging (MRI) with three-dimensional tissue tagging.
Multidirectional peak myocardial shortening strains and strain rates, as well as the
peak systolic displacement and velocity of the mitral valve annulus plane (MVP), were
considered as parameters of LV systolic function. The corresponding peak diastolic strain
relaxation rates and peak diastolic MVP velocity were used to assess diastolic function. The
effects of normal ageing were studied in people with no evidence of cardiac disease, and
compared with the effects of disease in patients with type 2 diabetes mellitus (DM).
In normal healthy subjects, systolic strain parameters were preserved, while
diastolic parameters were impaired, with age. DM patients showed impaired diastolic
function on correction for age, and systolic functional parameters were also impaired, even
though LV ejection fraction was normal. MVP systolic and diastolic motion were reduced
both with age and in DM patients. Systolic LV torsion was increased with age and in DM,
with no corresponding increase in torsional relaxation. Both systolic and diastolic function
parameters were regionally heterogeneous. With normal ageing, diastolic function was
impaired in a regionally non-uniform manner.
Thus, a complete assessment of LV function requires measurement of LV tissue
mechanics as well as chamber haemodynamics. MRI provides valuable information
regarding myocardial tissue behaviour, contributing to systolic and/or diastolic dysfunction,
which cannot be obtained otherwise. Systolic tissue dysfunction may develop concomitantly
in patients with diastolic dysfunction, even when global ejection fraction is preserved.
Regional analyses provide important information on how local changes contribute to global
function. The influence of age must be taken into account in studies of disease.
| Identifer | oai:union.ndltd.org:AUCKLAND/oai:researchspace.auckland.ac.nz:2292/5715 |
| Date | January 2004 |
| Creators | Fonseca, Carissa Grace. |
| Contributors | Young, Alistair A., Stewart, Ralph A. |
| Publisher | ResearchSpace@Auckland |
| Source Sets | University of Auckland |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated., https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm, Copyright: The author |
| Relation | PhD Thesis - University of Auckland, UoA1490451 |
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