Method and devices for treating atrial fibrillation by mass ablation

Abstract

Apparatus and method for ablating target tissue including a non-linear area of tissue in the left atrium of a patient. The method can include selecting an ablation apparatus having an ablator with a tissue engagement section, penetrating a chest cavity of the patient, and identifying the target tissue. The method can also include positioning the ablation apparatus adjacent to the target tissue so that the tissue engagement section can transfer ablation energy to the target tissue. The method can further include energizing the tissue engagement section with ablation energy in order to create a footprint on the non-linear area of tissue in the left atrium and to reduce an overall mass of excitable tissue in the left atrium.

1 . A method of ablating target tissue including a non-linear area of tissue in a left atrium of a patient, the method comprising: 
 selecting an ablation apparatus having an ablator with a tissue engagement section;    penetrating a chest cavity of the patient;    identifying the target tissue;    positioning the ablation apparatus adjacent to the target tissue so that the tissue engagement section can transfer ablation energy to the target tissue; and    energizing the tissue engagement section with ablation energy in order to create a footprint on the non-linear area of tissue in the left atrium and to reduce an overall mass of excitable tissue in the left atrium.    
     
     
         2 . The method of  claim 1  and further comprising choosing an ablation apparatus using at least one of radio frequency energy, thermal energy, cryogenic energy, chemical energy, pharmacological energy, ultrasound energy, microwave energy, laser energy, and radiation energy.  
     
     
         3 . The method of  claim 1  and further comprising choosing an ablation apparatus including at least one of a balloon, a mesh, a patch, a rolled electrode, a fan, a bipolar electrode, a wiper, and a crystal transmitter.  
     
     
         4 . The method of  claim 1  and further comprising penetrating the chest cavity by entering through at least one of a sub-xiphoid incision, a sub-costal incision, a sternotomy, a thoracotomy, and a trans-venous puncture.  
     
     
         5 . The method of  claim 1  and further comprising identifying the target tissue using at least one of direct visualization, X-ray, ultrasound, magnetic resonance imaging, positron emission tomography, computerized tomography, fluoroscopy, endoscopic observation, intra cardiac echo, and transesophageal echo.  
     
     
         6 . The method of  claim 1  and further comprising placing the ablation apparatus adjacent the outside of the left atrium by an epicardial approach.  
     
     
         7 . The method of  claim 1  and further comprising placing the ablation apparatus adjacent the inside of the left atrium by an endocardial approach.  
     
     
         8 . The method of  claim 1  and further comprising placing the ablation apparatus adjacent the left atrium by a transesophageal approach.  
     
     
         9 . The method of  claim 8  and further comprising energizing the tissue engagement section with ultrasound energy.  
     
     
         10 . The method of  claim 9  and further comprising focusing the ultrasound energy on the target tissue.  
     
     
         11 . The method of  claim 1  and further comprising transferring energy to a portion of the ablation apparatus at the tissue engagement section.  
     
     
         12 . The method of  claim 1  and further comprising: 
 removably placing the ablation apparatus in a delivery end of an insertion tool;    positioning the insertion tool into the patient through an incision;    directing the delivery end to a location adjacent the target tissue;    removing the ablation apparatus from the insertion tool; and    adjusting the ablation apparatus to bring the tissue engagement section in contact with the target tissue.    
     
     
         13 . The method of  claim 1  and further comprising affixing the tissue engagement section to the target tissue by at least one of a bio-adhesive, a vacuum, an inflatable balloon, a mechanical deflection, a magnetic field, a shape memory alloy, and a superelastic alloy.  
     
     
         14 . The method of  claim 1  and further comprising providing an insulator in the ablation apparatus to prevent damage to tissue adjacent the target tissue.  
     
     
         15 . An ablation apparatus for ablating target tissue of a patient, the ablation apparatus comprising: 
 an insertion tool having a proximal end, a distal end, and a lumen;    an ablator including a conductor and a tissue engagement portion, the conductor having a source end extending from the proximal end of the insertion tool and a delivery end coupled to the tissue engagement portion, the ablator removably inserted in the lumen; and    an energy source connected to the conductor;    the insertion tool being inserted into a patient so that the distal end is adjacent the target tissue, the conductor urging the ablator out of the lumen to engage the target tissue;    energy being conducted from the energy source to the ablator to create a footprint on the target tissue to reduce an overall mass of excitable tissue.    
     
     
         16 . The ablation apparatus of  claim 15  and further comprising a sensor connected to the ablator to sense the target tissue.  
     
     
         17 . The ablation apparatus of  claim 15  and further comprising a mapping tool to visualize the tissue engagement portion of the ablator.  
     
     
         18 . The ablation apparatus of  claim 15  wherein the insertion tool includes a catheter.  
     
     
         19 . The ablation apparatus of  claim 15  wherein the ablator includes a patch removably attachable to the target tissue, the patch including at least one of an adhesive patch, a tongue patch, a circular patch, a balloon patch, a suction patch, a chemical release patch, a rolled patch, a carbon patch, and a webbed patch.  
     
     
         20 . The ablation apparatus of  claim 15  wherein the ablator includes a skirt that can suction to the target tissue, the skirt receiving fluid for conducting the energy to the target tissue.  
     
     
         21 . The ablation apparatus of  claim 20  wherein the fluid is electrically conductive.  
     
     
         22 . The ablation apparatus of  claim 20  wherein the fluid is caustic.  
     
     
         23 . The ablation apparatus of  claim 20  wherein the fluid is thermally conductive.  
     
     
         24 . The ablation apparatus of  claim 15  wherein the ablator includes a balloon, the balloon being inflatable to occupy a cavity in the patient adjacent to the target tissue, the balloon being removably stored in the distal end of the insertion tool wherein the balloon is inflated causing the balloon to emerge from the insertion tool, and the balloon being positionable to cause the tissue engagement portion to bear against the target tissue.  
     
     
         25 . The ablation apparatus of  claim 15  wherein the ablator includes a chemical delivery system.  
     
     
         26 . The ablation apparatus of  claim 25  wherein the chemical delivery system includes a delivery method of at least one of diffusion, iontophoresis, mechanical injection, needle-less injection, and controlled slow-release delivery.  
     
     
         27 . The ablation apparatus of  claim 15  wherein the ablator includes a skirt and an adhesive tongue inside the skirt, the tongue moveable within the skirt to engage the target tissue, the skirt affixing the ablator to the target tissue by a vacuum.  
     
     
         28 . The ablation apparatus of  claim 15  wherein the tissue engagement portion includes a first bipolar tissue electrode and a second bipolar tissue electrode, wherein the first bipolar tissue electrode is applied to the interior of the left atrium endocardially, wherein the second bipolar tissue electrode is applied to the exterior of the left atrium epicardially, each of the first and second bipolar tissue electrodes connected to the energy source, energy being applied from the energy source to conduct from the first bipolar tissue electrode to the second bipolar tissue electrode to render a mass of left atrium tissue located between the first and second bipolar tissue electrodes at least one of non-contractile, non-viable, and unable to propagate an action potential.