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 and make contact with the conductor, providing an electrical pathway to the distal electrode. Also provided are vascular access systems including hemostasis valve and a guide catheter, guide wire torquers with adjustable contacts and methods of temporarily pacing a patient's heart.