Abstract: A single-pass endocardial lead electrode adapted for implantation in, on or about the heart and for connection to a system for monitoring or stimulating cardiac activity includes a lead body which is adapted for implantation within a single chamber of the heart, or multiple chambers of the heart. The lead includes a first distal end electrode which has a first electrical conducting surface. The lead body also has a second electrode which has a second electrical conducting surface. The first and second electrodes are either passively or actively attached to the wall of the heart. The lead body also includes a curved portion which facilitates the positioning of the second electrode. The main lead body alternatively includes a recess into which an atrial lead body and an active fixation element attached to one end can travel from a recessed position to a position for fixation to the wall of the heart. The active fixation element can also be moved by turning the terminal pin.

Abstract: 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.