Design of handle set for ablation catheter with indicators of catheter and tissue parameters

Abstract

An electrode coupling output system provides indication to the physician, via electrode guidance instrumentation, concerning the electrical coupling of an electrode, such as an ablative or mapping electrode, with a patient. The output can be provided to the physician via an output device incorporated into the handle set of the electrode catheter. For example, a visual, audio or mechanical output can be provided via the handle set. Additionally or alternatively, the output can be provided to the physician via a navigation system. The indication may be provided by changing the color or other display characteristics of the electrode on the navigation system display or by way of providing a waveform indicating the electrode coupling. In this manner, electrode coupling information is provided to a physician in a manner that minimizes physician distraction.

1 . (canceled) 
     
     
         2 . A method for use with an electrode catheter, the method comprising:
 passing a sensing current between a reference electrode and an ablation electrode of the electrode catheter while the ablation electrode is disposed within a blood pool of a patient body and is free of contact with tissue of the patient body;   measuring a baseline phase angle waveform while the ablation electrode is within the blood pool and free of contact with the tissue of the patient body;   after contacting the tissue with the ablation electrode, passing said sensing current between the ablation electrode and the reference electrode in connection with applying ablation energy to the ablation electrode;   measuring a current phase angle waveform while the ablation electrode contacts the tissue of the patient;   identifying a change between said baseline phase angle waveform and said current phase angle waveform; and   generating an output based on said change between said baseline phase angle waveform and said phase angle waveform.   
     
     
         3 . The method of  claim 2 , further comprising displaying at least one of:
 said baseline phase angle waveform;   said current phase angle waveform; and   said change between said baseline phase angle waveform and said current phase angle waveform.   
     
     
         4 . The method of  claim 3 , wherein said phase angle waveforms comprise a time series of phase angle values. 
     
     
         5 . The method of  claim 2 , wherein said passing said sensing current between the ablation electrode and the reference electrode in connection with applying said ablation energy to the ablation electrode comprises continuously passing said sensing current between the ablation electrode and the reference electrode. 
     
     
         6 . The method of  claim 5 , wherein said sensing current and said ablation energy have different frequencies and wherein said sensing current and said ablation energy are simultaneously applied to the ablation electrode. 
     
     
         7 . The method of  claim 2 , wherein said passing said sensing current between the ablation electrode and the reference electrode in connection with said applying ablation energy to the ablation electrode comprises periodically passing said sensing current between the ablation electrode and the reference electrode. 
     
     
         8 . The method of  claim 7 , further comprising:
 switching between a sensing current source and an ablation energy source wherein a single one of said sensing current and said ablation energy is applied to the ablation electrode.   
     
     
         9 . The method of  claim 2 , wherein said generating said output comprises generating an ablation electrode coupling level. 
     
     
         10 . The method of  claim 9 , wherein said ablation electrode coupling level comprises one of:
 insufficient coupling for an ablation procedure;   sufficient coupling for an ablation procedure; and   excessive coupling for an ablation procedure.   
     
     
         11 . The method of  claim 2 , wherein said generating said output comprises generating an output indicative of lesion formation in the tissue. 
     
     
         12 . The method of  claim 2 , wherein said generating said output comprises generating a change in a phase angle magnitude over time. 
     
     
         13 . The method of  claim 2 , wherein said passing said sensing current between the ablation electrode and the reference electrode comprises passing said sensing current between the ablation electrode and an external reference electrode on a surface of the body of the patient. 
     
     
         14 . The method of  claim 2 , wherein said passing said sensing current between the ablation electrode and the reference electrode comprises passing said sensing current between the ablation electrode and an internal reference electrode disposed within the patient body. 
     
     
         15 . A system for use with an electrode catheter, the system comprising:
 at least one signal generator connectable with an electrode catheter having an ablation electrode configured to apply at least one of a sensing current and ablation energy between the ablation electrode and a reference electrode;   a phase angle measurement circuit configured to measure phase angle waveforms between the ablation electrode and the reference electrode in response to at least one of the sensing current and the ablation energy;   a phase comparator configured compare a current phase angle waveform between the ablation electrode and the reference electrode with a baseline phase angle waveform between the ablation electrode and the reference electrode and generate an output indicative of a change between the current phase angle waveform and the baseline phase angle waveform; and   a display for displaying at least one of:
 the baseline phase angle waveform; 
 the current phase angle waveform; and 
 the output indicative of the change between the current phase angle waveform and the baseline phase waveform. 
   
     
     
         16 . The system of  claim 15 , wherein the signal generator comprises:
 a first signal generator configured to generate the sensing signal; and   a second signal generator configured to generate the ablation energy.   
     
     
         17 . The system of  claim 16 , further comprising a switch for selectively connecting one of the first signal generator and the second signal generator to the ablation electrode. 
     
     
         18 . The system of  claim 15 , wherein the display further comprises a navigation system, wherein the navigation system configured to monitor and display a position of the ablation electrode within a patient body. 
     
     
         19 . The system of  claim 15 , further comprising a memory, wherein the memory stores the baseline phase angle waveform. 
     
     
         20 . The system of  claim 15 , further comprising an assessment system, wherein the assessment system is configured to utilize the output indicative of the change between the current phase angle waveform and the baseline phase angle waveform to generate at least one of:
 an ablation electrode coupling level between the ablation electrode and patient tissue; and   an indication of lesion formation in patient tissue contacted by the ablation electrode.