A leadless pacing device may include a housing having a proximal end and a distal end, and a set of one or more electrodes supported by the housing. The housing may include a first portion and a second portion, with a guide wire port extending through the second portion. A guide wire lumen may extend through the second portion of the housing and the guide wire port may be located at a proximal end of the guide wire lumen. An exposed electrode may be located on a side of the housing that is opposite a side on which the guide wire port is located. The leadless pacing device may include a fixing member on the housing and extending radially from the housing. The leadless pacing device may further include a proximal member extending proximally from a proximal end of the housing. The proximal member may be elongated.