Mechanism for adjusting the exposed surface area and position of an

Abstract

An endocardial pacing and/or cardioversion/defibrillation lead having a plurality of electrodes and a mechanism for adjusting the exposed surface area of one or more electrode and/or the position and/or angular orientation of an electrode along a lead body. A fixed exposed, flexible, elongated commutator surface is provided extending along the lead body intermediate the proximal and distal lead body ends coupled by an electrical lead conductor extending to the proximal end of the lead body. A movable electrode assembly is provided that fits over and slides along the lead body, including the fixed commutator surface, that supports an exposed movable electrode on it. The movable electrode assembly includes at least one flexible, elongated, movable commutator surface within it that is electrically connected with the movable electrode. Electrical contact is established between the movable electrode and the lead connector end through contact of the fixed and movable commutator surfaces in a contact segment of contact area that varies with the relative movement of the movable contact surface with respect to the fixed contact surface. The position and exposed surface area of the movable electrode may be adjusted even further by use of a further electrode adjustable area outer insulating sheath positioned over the movable electrode assembly.