A mechanically expandable esophageal catheter has an elongated flexible body which carries at a distal end thereof one or more electrically conducting members. The conducting members are moveable laterally with respect to the body portion of the catheter by means of a mechanical structure contained therein....http://www.google.de/patents/US5117828?utm_source=gb-gplus-sharePatent US5117828 - Expandable esophageal catheter
