An electrosurgery system includes a catheter including one or more active electrodes adapted to be positioned adjacent biological tissue at an in vivo treatment site in a patient and to deliver electrical energy to the biological tissue. The electrosurgery system further includes a dispersive electrode assembly including a conductive element having a first end and a second end. The dispersive electrode assembly is configured to surround a waist of the patient such that a first surface of the conductive element is in contact with the waist and the first end of the conductive element is adjacent the second end of the conductive element.