Optimization of cardiac resynchronization therapy in atrial fibrillation and sinus rhythm

The prevalence of atrial fibrillation (AF) is high in patients treated with cardiac resynchronization therapy (CRT). However, patients with AF are not well represented in the landmark trials that established the clinical benefit of CRT. This indicates the need for further refinement how to handle AF in patients treated with CRT. The aim of the current thesis was to improve and refine the current CRT selection criteria in AF and sinus rhythm patients through evaluation of the mechanisms underlying (non-)response to CRT. In part I the clinical and echocardiographic response rates to CRT were compared between atrial fibrillation patients and sinus rhythm patients. The influence of AF on short and long-term response was studied in chapter 2 and 3. Predictors for response to CRT in atrial fibrillation patients were investigated in chapter 1. Long term prognosis and outcome between atrial fibrillation patients treated with CRT and sinus rhythm patients was studied in chapter 2. In chapter 3 we studied whether CRT prevents new-onser AF and, furthermore, how new-onser AF influences response and prognosis to CRT. In part II predictors for response to CRT were studied. Exercise related factors that influence response to CRT were studied in . chapter 4. In chapter 5 we examined the influence of interlead distance measured by thoracic X-ray on response to CRT. Furthermore, the influence of the septal to lateral delay and interventricular mechanical delay were examined. With the improvements in device possibilities the treatment of the CHF patient can be improved. This is described in a case report (chapter6). Finally, in the discussion and future directions section of this thesis the results and implications of this thesis are discussed in the context of other studies. Future perspectives of the optimal use of different non-invasive imaging modalities in patients undergoing CRT implantation, both before implantation as well as during follow-up (evaluation of therapy success and optimization of pacemaker settings), are discussed.