US Patent 6979312 Steerable sheath catheters

The invention is a steerable catheter having a pull wire, a central lumen and a control handle. The central lumen is maintained in a circular shape without obstructions diminishing the useful inter-diameter. The pull wire friction is also reduced by using one wire of larger diameter to create the lumen for the pull wire of smaller diameter, thus reducing the friction on the pull wire and reducing the locking of the catheter body around the pull wire at bends preventing movement of the pull wire. A control handle with a simple operational mechanism that allows direct access to a continuous central lumen from the proximal end of the catheter.