Optimal site selection & guidance during endocardial Cardiac Resynchronisation Therapy

Student thesis: Doctoral ThesisDoctor of Philosophy


Heart failure is a complex clinical syndrome associated with a significant morbidity and mortality burden. CRT has emerged as one of the few effective treatments for heart failure, however, around 30%-50% of patients fail to respond. Novel approaches to CRT have been devised and of these endocardial pacing, shows the most promise. Pacing endocardial tissue is associated with several anatomical and physiological advantages over conventional epicardial CRT and is not constrained by coronary sinus anatomy meaning there is greater potential to identify and accurately target a specific pacing site. 
This thesis looks to assess the practice of biventricular endocardial CRT and evaluate which metrics can usefully identify the optimal LV endocardial pacing site. It will compare two approaches to biventricular endocardial pacing; empirical site selection during biventricular endocardial CRT and a guided approach, where the optimal site is identified and targeted using a variety of advanced image guidance techniques. 
The thesis will include a brief review of the pathophysiology of heart failure and the development of LV dyssynchrony. An exploration of the causes of non-response to conventional transvenous, epicardial CRT will lead into a discussion of the physiological benefits of biventricular endocardial pacing. The thesis will also outline the different approaches to delivering biventricular endocardial CRT. A detailed evaluation of the importance of site selection including how to identify and target the optimal LV pacing site will complete the background literature review. 
The thesis will then compare the efficacy of biventricular endocardial pacing in comparison to transvenous, epicardial CRT with a view to assessing the superiority of an endocardial approach. This analysis will also include an exploration of which metrics can usefully predict the optimal LV endocardial pacing site. 
Further analysis will compare two opposing strategies of biventricular endocardial pacing using a novel, leadless biventricular endocardial pacing system. In the first analysis, the approach of empirical site selection will be analysed. This study will include an assessment of the safety and efficacy of the leadless, endocardial pacing system. This will be compared against a strategy of pre-procedural site selection to identify the optimal LV endocardial pacing site. Advanced image guidance technology will then be used to target the chosen location. The safety and efficacy of this approach will also be evaluated.
Date of Award1 Sept 2019
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorReza Razavi (Supervisor)

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