Abstract: A pass-through electrode device includes a tubular member including a proximal end, a distal end sized for introduction into a patient's body, a lumen extending between the proximal end and the distal end, and one or more pass-through electrodes on the distal end. Each pass-through electrode includes an outer portion on an outer wall of the tubular member, an inner portion exposed within an inner wall of the lumen, and is passive, e.g., electrically isolated and/or unconnected to other electrodes or components of the device. A system is also provided that includes an outer tubular member including one or more pass-through electrodes and a procedure device introducible through and deployable from the tubular member for performing a procedure, e.g., mapping and/or ablation. The procedure device includes one or more active electrodes that may be aligned with pass-through electrodes when the device is at least partially positioned within the outer member.