An intravascular catheter is positionable within a blood vessel for use in transvenous stimulation of targets external to the wall of the blood vessel. The catheter includes a catheter body, a support at the distal end of the catheter body, and a plurality of electrodes carried by the support. At least a portion of the support being inflatable within the blood vessel to bias at least a portion of the plurality of electrodes into contact with the blood vessel wall.