Systems and methods for temporarily pacing a patient's heart are provided. One system includes a hemostasis valve with an adjustable electrical connection, the adjustable electrical connection having one or more adjustable contacts. The adjustable contacts have a first, radially expanded configuration and a second, radially constricted configuration. In the radially constricted configuration, the adjustable contacts are configured to pierce through a layer of an elongate medical device that is disposed in the hemostasis valve. The elongate medical device has a distal electrode and a conductor extending along a portion of the elongate medical device. The adjustable contacts pierce through a make contact with the conductor, providing an electrical pathway to the distal electrode. Also provided are vascular access systems including a hemostasis valve and a guide catheter, guide wire torquers with adjustable contacts and methods of temporarily pacing a patient's heart.