A device, system, and method for providing support to a mapping catheter during mapping or pacing and for adjusting the diameter of a distal loop portion of currently available mapping catheters. A medical device support device includes an elongate body defining a wall and an at least substantially linear proximal portion and a distal portion being transitionable between an at least substantially linear configuration and an expanded configuration, the elongate body defining a lumen extending through the proximal portion and distal portion, the lumen being entirely surrounded by the wall in the proximal portion and being partially surrounded by the wall in the distal portion. For example, the lumen may be sized to receive a mapping catheter therein such that adjustment of the configuration or diameter of the distal portion of the elongate body will likewise modify the configuration or diameter of the distal portion of the mapping catheter.
