Novel cardiac imaging technologies : implications in clinical decision making

Abstract

The objectives of this thesis were to investigate the role of novel cardiac imaging technologies in the current clinical daily practice with the advent of novel therapies. In Part I, the role of novel imaging modalities to assess left ventricular mechanics will be discussed, focusing on 1) the incremental value of novel myocardial deformation indices over conventional echocardiographic parameters to characterize left ventricular performance in several cardiac conditions (Part IA); 2) the relationship between left ventricular synchronicity and mechanics (Part IB); and the effect of different therapies on left ventricular mechanics (Part IC). The value of twodimensional speckle tracking imaging to characterize all these left ventricular electromechanical aspects will be thoroughly described and the additional value of integrated backscatter imaging and the study of left ventricular vortex formation will be introduced. The evaluation of left atrial myocardial tissue properties in patients with atrial fibrillation undergoing radiofrequency catheter ablation procedure will be the focus of Part II. Integrated backscatter imaging was used to evaluate the fibrosis content of the left atrial wall and related to atrial fibrillation recurrence rate after radiofrequency catheter ablation (Chapter 18). As previously discussed, the fibrosis content of the left atrial wall may determine the deformation properties of the myocardium and the reverse remodeling of the left atrium after ablation (Chapter 19). Therefore, tissue Doppler derived strain may predict the occurrence of left atrial reverse remodeling after radiofrequency catheter ablation. In addition, tissue Doppler imaging may be useful to evaluate the electromechanical properties of the left atrial wall, in close relation with the occurrence of new atrial fibrillation onset and perpetuation of the arrhythmia (Chapter 20). Finally, the role of novel cardiac imaging modalities in the emerging transcatheter valve therapies will be discussed in Part III. Part IIIA will outline the prevalence of valvular heart disease in relation to several clinical conditions (post-Streptococcal reactive arthritis and use of dopamine agonist therapy) and ageing. Particularly, in elderly patients who show an increased operative morbidity and mortality, the advent of transcatheter valve repair/replacement techniques has provided alternative therapies to surgery. Part IIIB will discuss the role of 3-dimensional imaging techniques (real-time 3-dimensional echocardiography and multi-detector row computed tomography) in the pre-procedural screening and to guide the procedure.