US Patent 7643886 Hydraulic actuation of lead fixation member

A medical electrical lead includes a primary lumen, a hydraulic lumen, and a fixation portion including at least one expandable fixation member. The fixation member communicates with a plunger disposed in the hydraulic lumen, and is actuated from an expanded configuration to a collapsed configuration by the introduction and release of hydraulic pressure in the hydraulic lumen. The hydraulic actuation of the fixation member allows for the delivery, positioning, re-positioning, and/or retrieval of the lead.