Variable curve electrophysiology catheter

An electrode tip assembly attachable to the end of a catheter for supporting a tip electrode for percutaneous insertion into a living body comprising

• an elongated body bendable in response to external forces to steer the tip electrode, the body having a proximal end for attachment to the catheter and a distal end for carrying the tip electrode and at least one steering wire attached to the body for transmitting bending force to the body from a remote control mechanism, said control mechanism being operatively connected to said steering wire to apply forces thereto, said catheter being bendable in response to bending of said body,
• an axially movable stiffening member providing a variable fulcrum for bending of the body in response to an applied bending force, and
• a control stylet extending through the length of the catheter and attached to the stiffening member for moving the stiffening member in a distal/proximal direction.

A cardiac probe including a distal tip assembly supporting at least one electrode for measurement of electrical activity within the heart or for ablation of cardiac tissue, comprising

• an elongated, flexible tubular catheter body having a proximal end and a distal end, said distal tip assembly being attached to said distal end of said catheter body,
• said probe including a handle portion provided with a steering mechanism attached to the proximal end of said catheter body and a steering wire assembly connected to said steering mechanism and extending from said handle to said distal tip assembly for bending said assembly in response to forces applied to said steering mechanism,
• characterized in that a stiffening member is contained in said catheter body adjacent to said distal tip assembly, said stiffening member being manipulatable by a manually moveable control located in said handle said control being operatively connected to said stiffening member and wherein manipulation of said control moves said stiffening member relative to said steering mechanism and thereby defines a fulcrum moveable relative to said steering mechanism that, when moved, changes the length of said distal tip assembly that is deflected when said distal tip assembly is caused to bend.