Decoding atrial fibrillation: Personalized identification and quantification of electropathology

Electrophysiological mapping-guided ablation strategies targeting atrial fibrillation (AF) have improved considerably over the past few years. However, it remains a major challenge to design effective strategies for particularly persistent AF. This can be partially explained by the inadequate understanding of the mechanisms and electropathological substrate underlying AF. Progression of AF is accompanied by structural and electrical remodeling, resulting in complex electrical conduction disorders, which is defined as electropathology. The severity of electropathology thus defines the stage of AF and is a major determinant of the effectiveness of AF therapy. In this thesis, features of electrophysiological properties of atrial tissue have been explored, developed and quantified during normal sinus rhythm, programmed electrical stimulation and AF. In addition, inter- and intra-individual variation in these quantified parameters has been examined in patients with and without prior episodes of AF. The most suitable objective parameters will aid in the identification of patients at risk for early onset or progression of AF. Part I of this thesis focusses on quantified electrogram features related to electropathology. In part II, abnormalities in wavefront propagation due to heterogeneous conduction properties were explored. Part III focusses on identification of post-operative AF and the relation with electropathology. In part IV of this thesis, some clinical implications of high-resolution mapping during cardiac surgery and application of quantified electrophysiological features are discussed.