Page 173 - The role of advanced echocardiography in patients with ischemic heart disease - Rachid Abou

SUMMARY
The general introduction (Chapter 1) of this thesis provides a practical guide on the technical aspects of left ventricular (LV) global longitudinal strain (GLS) measurements (derived from speckle tracking echocardiography) and summarizes the available evidence on the clinical use of this parameters. Left ventricular ejection fraction (LVEF) is the most frequently used parameter to characterize left ventricular systolic function and is usually included in practice guidelines to select the therapeutic strategies. However, LVEF has many limitations, not only in terms of reproducibility of the measurement but also in terms of not being accurate enough to detect early LV systolic dysfunction. As the assessment of LV systolic function is pivotal for the diagnosis, risk stratification and management of patients with cardiovascular disease. Myocardial strain imaging using echocardiography has shown that LV GLS is more sensitive to detect subclinical LV systolic dysfunction and is more reproducible than LVEF. Furthermore, we provide a glimpse into future clinical applications derived from speckle tracking echocardiography that are increasingly used in clinical practice.
Part I: Insight into left sided mechanics in non-structural heart disease
In the first part, conventional and advanced echocardiographic techniques are used to evaluate subject with no structural heart disease to gain more insight into left sided mechanics in a real-world ageing population.
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Data with regards to regional and layer-specific LV GLS are scarce. These parameters may further aid in the risk stratification and better understanding of LV mechanics. Especially in patients with ischemic heart disease in whom the myocardial tissue is affected from the endocardium to the mid-myocardium and the epicardium. In Chapter 2 we evaluated the effect of aging on level and layer-specific LV GLS. We report an increasing gradient from basal to mid and apical and a decreasing gradient from endocardium to mid-myocardium and epicardium which does not seem to be affected by age in our study population. This gradient is probably due to the composition and orientation of the myocardial fibers of the left ventricle.
Chapter 3 provides more insight into left atrial (LA) (electromechanical) mechanics as evaluated by echocardiography and the conventional electrocardiogram. With increasing age, the LA conduction becomes slower and the LA compliance reduces, suggesting the presence of age-related fibrotic changes of LA tissue. We demonstrate this by more prolonged PA-TDI (echocardiographic marker for total atrial conduction time), prolonged P-wave dispersion (electrocardiographic marker for atrial conduction
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