Device and method for forming a lesion

Abstract

The invention provides apparatus and methods for mapping conduction pathways and creating lesions in the heart wall for the treatment of atrial fibrillation. The apparatus may include at least one epicardial ablation probe having a plurality of electrodes for creating a lesion. The apparatus and method facilitate the formation of a lesion which electrically isolates the pulmonary veins from the surrounding myocardium.

What is claimed is:  
     
         1 . A system for ablating tissue from a location between the epicardium and the pericardium, comprising: 
 a first device capable of being advanced into the pericardial space;    a second device slidably coupled to the first device, the second device having an expandable device; and    an ablating device mounted to at least one of the first and second devices, the ablating device being configured to create a lesion.    
     
     
         2 . The system of  claim 1 , wherein: 
 the ablating device is mounted to the second device.    
     
     
         3 . The system of  claim 1 , wherein: 
 the ablating device is mounted to the first device.    
     
     
         4 . The system of  claim 1 , further comprising: 
 a sensor coupled to at least one of the first and second devices, the sensor being positioned adjacent the ablating device to detect a location of a previously formed ablation for proper positioning of the ablating device.    
     
     
         5 . The system of  claim 1 , wherein: 
 the first device has an anchor which holds the first device at a location between the pericardium and epicardium.    
     
     
         6 . A method of forming a continuous ablation across a pericardial reflection when ablating tissue from a position between the pericardium and epicardium, the method comprising the steps of: 
 providing a first ablating device having a first ablating element and a second ablating device having a second ablating element, the first ablating device having a penetrating element;    introducing the first and second ablating devices into the space between the pericardium and the epicardium;    penetrating a pericardial reflection with the penetrating element.    
     
     
         7 . The method of  claim 6 , wherein: 
 the providing step is carried out with the first and second ablating devices interlocking.    
     
     
         8 . The method of  claim 7 , further comprising the step of: 
 interlocking the first and second ablating devices after the penetrating step.    
     
     
         9 . A method of ablating tissue from a location between the epicardium and the pericardium, comprising: 
 providing an ablating device having an ablating element;    introducing the ablating device into the pericardial space;    forming a first lesion with the ablating element;    moving the ablating device; and    forming a second lesion continuous with the first lesion.    
     
     
         10 . The method of  claim 9 , wherein: 
 the forming and moving steps are carried out to form a lesion adjacent the pulmonary veins.    
     
     
         11 . The method of  claim 9 , wherein: 
 the providing step is carried out with the ablating device being slidably coupled to a first device;    the method further comprising the steps of advancing the first device ahead of the ablating device; and    the moving step being carried out by slidably moving the ablating device along the first device.    
     
     
         12 . The method of  claim 11 , wherein: 
 the providing step is carried out with the first device having an anchor to hold a part of the device at a location in the pericardial space.    
     
     
         13 . The method of  claim 12 , wherein: 
 the providing step is carried out with the anchor being a device selected from the group consisting of a suction port, tine, and an expandable member.    
     
     
         14 . The method of  claim 9 , wherein: 
 the ablating device has means for locating the first lesion;    the method further comprising the steps of locating the first lesion with the locating means before forming the second lesion.    
     
     
         15 . A method of creating a lesion from a location in the pericardial space, comprising the steps of: 
 providing a first device and a second device slidably coupled to the first device, the second device having an expandable member mounted thereto, at least one of the first and second devices having an ablating element;    introducing a first and second devices into the pericardial space;    ablating tissue to form a first lesion with the ablating element;    moving at least one of the first and second devices relative to the other; and    forming a second lesion after the moving step.    
     
     
         16 . The method of  claim 15 , wherein: 
 the providing step is carried out with the ablating element being mounted to the first device.    
     
     
         17 . The method of  claim 16 , wherein: 
 the providing step is carried out with the first device having a plurality of ablating elements; and    the forming step is carried out with another of the ablating elements on the first device.    
     
     
         18 . The method of  claim 16 , wherein: 
 the providing step is carried out with at least one of the first and second devices having means for locating the first lesion; and    the method further comprising the step of locating the first lesion with the locating means before the forming step.    
     
     
         19 . A method of forming a lesion from a location in the pericardial space, comprising the steps of: 
 introducing a first ablating device into the pericardial space, the ablating device having an ablating element;    advancing the first ablating device to a pericardial reflection;    penetrating the pericardial reflection with the first ablating device; and    forming a first lesion with the ablating element.    
     
     
         20 . The method of  claim 19 , further comprising the step of: 
 interlocking a first part of the first ablating device with a second part of the first ablating device after the penetrating step.    
     
     
         21 . The method of  claim 19 , further comprising the steps of: 
 introducing a second ablating device into the pericardial space; and    interlocking the first and second ablating devices after the penetrating step.    
     
     
         22 . A method of forming a lesion beneath a pericardial reflection, comprising the steps of: 
 providing a first device having an emitter and a second device having a sensor;    positioning the first device on a side of a pericardial reflection;    emitting energy from the emitter after the positioning step; and    moving the second device to a position on the opposite side of the pericardial reflection using the sensor which senses the energy emitted by the emitter.    
     
     
         23 . The method of  claim 22 , further comprising the step of: 
 penetrating the pericardial reflection with at least one of the first and second devices.    
     
     
         24 . The method of  claim 23 , further comprising the step of: 
 interlocking the first and second devices after the penetrating step.    
     
     
         25 . The method of  claim 22 , further comprising the step of: 
 forming a lesion beneath the pericardial reflection with at least one of the first and second devices.