Systems and methods for RF ablation using jet injection of a conductive fluid

Abstract

A method of preparing and ablating heart tissue includes a pre-treatment step of delivering a jet of conductive fluid to a portion of heart tissue. The conductive fluid is delivered using an injection device such as a hand-held jet injector, probe, or catheter. After injecting the heart tissue with the conductive fluid, RF energy is delivered to the site of the injection to form a lesion. The method enables a physician to produce large and accurately placed lesions within the treated tissue.

1 - 12 . (Cancelled).  
   
   
       13 . A method for ablating tissue comprising the steps of: 
 providing an injector device adjacent to a portion of the tissue, the injector device including a plurality of ports and a plurality of electrodes; and    injecting the tissue with a jet of conductive fluid from the injector device, the jet of conductive fluid entering the tissue via the plurality of ports; and    applying RF energy to the tissue containing the injected conductive fluid using the plurality of electrodes so as to form a lesion.    
   
   
       14 . The method according to  claim 13 , wherein during the step of applying RF energy, the maximum temperature of the tissue is maintained below 100° C.  
   
   
       15 . The method according to  claim 13 , further comprising the step of cooling the electrode during the step of applying RF energy.  
   
   
       16 . The method according to  claim 13 , wherein the step of injecting is performed at a pressure within the range of about 500 psi to about 1500 psi.  
   
   
       17 . The method according to  claim 13 , wherein the conductive fluid is a solution selected from the group consisting of sodium chloride, potassium chloride, sodium bicarbonate, sodium citrate, and potassium citrate.  
   
   
       18 . The method according to  claim 13 , wherein the conductive fluid comprises an ionic radiographic contrast material.  
   
   
       19 . The method according to  claim 13 , wherein the conductive fluid contains a dye.  
   
   
       20 . The method according to  claim 13 , wherein after application of the RF energy a legion is formed having a depth of with the range of about 1 mm to about 10 mm.  
   
   
       21 . A device for injecting a conductive solution into tissue comprising: 
 source of pressurized gas;    a syringe having at least one nozzle at one end thereof, the source of pressurized gas being in fluid communication with a plunger contained within the syringe;    a conductive fluid stored within the syringe; and    a switch for releasing a pressurized gas from the source into the syringe so as to cause the device to deliver a jet of conductive fluid at a speed sufficient to penetrate tissue to a depth within the range of about 2 mm to about 5 mm.    
   
   
       22 . A method of forming a lesion within tissue comprising the steps of: 
 providing access to the heart of a patient;    injecting a portion of the tissue with a jet of conductive fluid to a depth within the range of about 2 mm to about 5 mm; and    ablating at least some of the tissue injected with the jet of conductive solution using RF ablation.    
   
   
       23 . A RF ablation probe comprising: 
 a handle;    a shaft attached to the handle;    a distal section having a lumen therethrough, the distal section including a plurality of ports oriented on one side of the distal section, the distal section further including a plurality of RF electrodes; and    a source of pressurized conductive-fluid connected to the lumen of the probe.    
   
   
       24 . The RF ablation probe of  claim 23 , wherein the distal section comprises hypotube having an internal diameter within the range of about 0.010″ to about 0.025″.  
   
   
       25 . The RF ablation probe of  claim 23 , wherein the plurality of ports have diameters within the range of about 0.002″ to about 0.004″.  
   
   
       26 . The RF ablation probe of  claim 23 , wherein the source of pressurized conductive fluid is pressurized so as to produce an injection pressure within the range of about 500 psi to about 1500 psi.  
   
   
       27 . A RF ablation catheter comprising: 
 a handle;    a shaft attached to the handle;    a distal segment having a lumen therethrough, the distal segment including a plurality of ports oriented on one side of the distal segment, the distal segment further including a plurality of RF electrodes; and    a source of pressurized conductive fluid connected to the lumen of the catheter.