Multiple techniques have been developed to characterize the temporal and spatial distribution of electrical activation.144 The simplest technique uses several multipole catheters plus a roving catheter that is sequentially positioned in different regions of interest and measures local activation time. Electroanatomic mapping sys- tems and specialized multielectrode catheters, such as circular or multispline catheters, can map simultaneously from mul- tiple sites and improve the speed and resolution of mapping. 2.5.2. Tools to Facilitate Ablation, Including 3-Dimensional Electroanatomic Mapping Several tools have been developed to facilitate arrhythmia mapping and ablation, including electroanatomic 3-dimen- sional mapping and magnetic navigation. Potential benefits of these technologies include more precise definition or localiza- tion of arrhythmia mechanism, spatial display of catheters and arrhythmia activation, reduction in fluoroscopy exposure for the patient and staff, and shortened procedure times, particu- larly for complex arrhythmias or anatomy.145 Disadvantages include higher cost, as well as additional training, support, and procedure preparation time. Several studies have dem- onstrated the advantages of electroanatomic mapping, with IIb B-R Sotalol may be reasonable for ongoing management in patients with symptomatic SVT who are not candidates for, or prefer not to undergo, catheter ablation.114 See Online Data Supplement 2. Sotalol is a class III antiarrhythmic agent with beta-blocker properties. Unlike flecainide and propafenone, it can be used in patients with structural heart disease or ischemic heart disease. 