In the last two decades new mathematical and computational models and systems have been applied to the clinical cardiology, which continue to be developed particularly to quantify and simplify anatomy, physio-pathological mechanisms and treatment of many patients with cardiac arrhythmias. The Authors report our large experience on electroanatomical mapping systems and techniques that are currently used to quantify and analyze both anatomy and electrophysiology of the heart. In the last 15 years the Authors have performed more than 15,000 invasive catheter ablation procedures using different non-fluoroscopic three-dimensional (3D) electroanatomical mapping and ablation systems (CARTO, Ensite) to safely and accurately treat many patients with different cardiac arrhythmias particularly those with atrial fibrillation with a median age of 60 years (IQR, 55-64). The Authors have also developed and proposed for the first time a new robotic magnetic system to map and ablate cardiac arrhythmias without use of fluoroscopy (Stereotaxis) in >500 patients. Very recently, epicardial mapping and ablation by electroanatomical systems have been successfully performed to treat Brugada syndrome at risk of sudden death in a series of patients with a median age of 39 years (IQR, 30-42). Our experience indicates that electroanatomic mapping systems integrate several important functionalities. (1) Non-fluoroscopic localization of electrophysiological catheters in three-dimensional space; (2) Analysis and 3D display of cardiac activation sequences computed from local or calculated electrograms, and 3D display of electrogram voltage; (3) Integration of ‘electroanatomic’ data with non-invasive images of the heart, such as computed tomography or magnetic resonance images. The widespread use of such 3D systems is associated with higher success rates, shorter fluoroscopy and procedure times, and accurate visualization of complex cardiac and extra-cardiac anatomical structures needing to be protected during the procedure.