Retractable lead with mesh screen

摘要

A retractable lead having a distal tip electrode is adapted for implantation on or about the heart and for connection to a system for monitoring or stimulating cardiac activity. The electrode includes a fixation helix for securing the electrode to cardiac tissue, which may or may not be electrically active. The electrode further includes an electrode tip having a mesh screen disposed on a surface at the distal end of the electrode tip, which can be used as a sensing or pacing interface with the cardiac tissue. The mesh screen provides a guiding mechanism for the helix as it travels out of the electrode for securing the electrode to the heart or other muscle or organ. The guiding mechanism may include a groove within the mesh screen. Alternatively, the guiding mechanism includes a guiding bar on which the fixation helix rides on during extension or retraction.