Pranav Bhagirath

209 General discussion This thesis was focused on designing novel strategies for the assessment of the arrhythmogenic substrate of atrial fibrillation (AF) and idiopathic ventricular tachycardia. Firstly, the drawbacks of the currently utilized techniques were evaluated. For AF this encompassed the evaluation of the workup strategy using the key non-invasive imaging modalities. In idiopathic ventricular tachycardia both the invasive and non-invasive electrical assessment were compared. The identified shortcomings were addressed by designing and validating new imaging methods. This chapter will discuss the outcomes of this thesis and provide future research perspectives. IMAGING BASED SUBSTRATE ANALYSIS IN ATRIAL FIBRILLATION Various non-invasive imaging modalities, including transthoracic echocardiography, trans-esophageal echocardiography, computed tomography and cardiac magnetic resonance (CMR) are currently employed in the treatment strategy of AF 1-4 . All these techniques have their advantages and limitations, and due to a different gold standard for each step in the workup, a multimodality approach is advocated in the daily practice 1, 5 . An increasingdemand for catheter ablationprocedures has resulted inelectrophysiology centers with high volume practices, necessitating an optimization of the existing work- up. Moreover, ongoing technological developments have increased the capability of the individual techniques and permit a single modality approach that can supply consistent and uniform imaging data, applicable during the workup, guidance and evaluation of ablation procedures 6, 7 . Today, the most promising modality seems to be cardiac magnetic resonance imaging as its ability to visualize anatomy combinedwith information about tissue characteristics enable a detailed workup to be performed. However, it is the least frequently used due to time constraints and restrictions for some patient groups. Optimized CMR based workflow To improve the usability of CMR, a standardized CMR based workflow for patient selection and procedural guidance for AF ablation was designed. The clinical utility and feasibility of this workflow was investigated by evaluating: (1) The ability to assess for left atrial appendage thrombus, left atrial (LA) volume and sphericity