Multimodal cardiac imaging in the clinical electrophysiology laboratory

1 Introduction Multimodal cardiac is differently intended and addressed by scientist of different disciplines. This is also evident reading some of the papers presented in this conference [1-4]. The same terminology can be used to define integration of data obtained with different non invasive cardiac imaging methods, inverse reconstruction of cardiac activation patters from surface mapping data, or three-dimensional localization of cardiac sources and transfer of the results into anatomical images. All the above mentioned approaches are valid and can be clinically useful, however some of them can be unnecessary or even redundant in the cardiac electrophysiology laboratory, where the cardiologist's needs are: 1) definition of the arrhythmogenic mechanism(s) underlying the clinical arrhythmia under investigation, 2) precise and reproducible catheter placement right on (or as close as possible to) the arrhythmogenic substrate, 3) validation of the substrate as responsible for the arrhythmia 4) ablation of the substrate and 5) minimal invasivity and X-ray exposure. Whereas point 1 had been sufficiently fulfilled, for many years, using single or biplane fluoroscopic imaging, after the introduction of catheter ablation the need has become evident of a better anatomical definition of catheter placement and of three-dimensional integration of the electrophysiological data. For a long while this electroanatomical integration in the EP laboratory has been roughly achieved only through a difficult mental process of the cardiologist using catheter endocardial mapping and fluoroscopy [5,6]. This however was an imprecise, time-consuming approach, which implies prolongation of the invasive procedures and of patient irradiation time. Moreover two-dimensional fluoroscopic imaging was anatomically misleading. In fact the fluoroscopic nomenclature and classification of arrhythmogenic structures, like for instance accessory pathways, use until two years ago were wrong when compared with their true anatomical position [7]. New methods therefore are desirable, to simplify precise placement of mapping and ablation electrocatheters, to achieve a better anatomical integration of electrophysiological information and localization of arrhythmogenic targets. Furthermore it would be ideal for the interventional electrophysiologist to start the invasive procedure having a preoperative localization of the arrhythmogenic target already marked into a three-dimensional anatomical reconstruction of a 3D model of the patient's heart, scaled on the screen at the same size of fluoroscopic bi-dimensional images and interactively rotable by the operator. The system should also provide real time imaging of the distal terminal of the mapping and ablation catheter, and compare its 3D coordinates with those of the preoperatively defined arrhythmogenic target [8]. With …