Optic-based contact sensing assembly and system

Abstract

A contact sensing assembly including a catheter and an electrode including a tip portion and a base portion, and a generally central axis, with the electrode being connected to a distal end of the catheter. Optical sensor(s) may be provided for emitting and/or receiving an optical signal, with a part of the optical signal being transverse to the central axis. Optical interference member(s) may be provided for interfering with the optical signal. A method for sensing contact force exerted by an electrode on a tissue includes directing an optical signal along a portion of a catheter, emitting and/or receiving an optical signal, with a part of the optical signal being at a predetermined angle relative to the central axis, and sensing changes in intensity of the optical signal based on displacement associated with the electrode tip portion based on the contact force exerted by the electrode on the tissue.

1 .- 83 . (canceled) 
     
     
         84 . A method for sensing contact force exerted by an electrode on a tissue comprising:
 directing an optical signal along at least a portion of a tubular body of a catheter having a proximal end and a distal end;   connecting an electrode including a tip portion and a base portion, and a longitudinal axis, to the distal end of the catheter;   at least one of emitting and receiving an optical signal, at least a part of the optical signal being at a predetermined angle relative to the longitudinal axis; and   sensing changes in intensity of the optical signal responsive to displacement associated with the electrode tip portion based on the contact force exerted by the electrode on the tissue.   
     
     
         85 . The method according to  claim 84 , wherein the predetermined angle is approximately 0°. 
     
     
         86 . The method according to  claim 84 , wherein the predetermined angle is greater than approximately 0°. 
     
     
         87 . The method according to  claim 84 , further comprising determining corresponding contact force vectors between the electrode and the tissue in contact with the electrode by evaluating the sensed changes in intensity. 
     
     
         88 . The method according to  claim 87 , wherein the contact force vectors include an axial component of the contact force and a transverse component of the contact force. 
     
     
         89 . The method according to  claim 88 , further comprising calibrating an optical sensor that emits and receives the optical signal. 
     
     
         90 . The method according to  claim 88 , further comprising calibrating the optical sensors by measuring an intensity of the respective optical signal for each optical sensor at zero-force (I0x), measuring an intensity of the respective optical signal for each optical sensor at a force greater than zero (Ix), and determining the relative intensity (Irx) between Ix and I0x, for each optical sensor as follows: Irx=Ix−I0x. 
     
     
         91 . The method according to  claim 90 , further comprising determining the axial and transverse components of contact force as a function of an angle of attack of the electrode relative to the tissue. 
     
     
         92 . The method according to  claim 90 , further comprising determining regression curves for the axial and transverse components of the contact force for a predetermined contact force range. 
     
     
         93 . The method according to  claim 89 , further comprising using the calibrated optical sensor to determine the axial and transverse components of the contact force. 
     
     
         94 . The method according to  claim 93 , further comprising determining the contact force magnitude as a function of the axial and transverse components of the contact force. 
     
     
         95 . The method according to  claim 93 , further comprising determining an angle of attack of the electrode relative to the tissue as a function of the axial and transverse components of the contact force. 
     
     
         96 . The method according to  claim 93 , further comprising determining an angle of rotation of the electrode relative to the tissue as a function of the change in intensity and phase angle of the optical sensor. 
     
     
         97 . The method according to  claim 84 , wherein the electrode performs one of RF ablation, HIFU ablation, laser ablation, cryo ablation, ultrasonic imaging, electrical pacing, EP pacing, electrical sensing, and EP sensing. 
     
     
         98 . The method according to  claim 84 , wherein the sensed contact force is utilized for at least one of:
 a) automatically limiting a maximum contact force;   b) warning of a high or unacceptable contact force;   c) giving visual or audible feedback to a practitioner regarding a tissue contact force;   d) warning of a loss of contact force or contact; and   e) warning of a contact force which is too low.