Methods of treating cardiac arrhythmia

Abstract

Methods and apparatus of embodiments of the invention are adapted to treat tissue inside a patient's body. Aspects of the invention can be used in a wide variety of applications, but certain embodiments provide minimally invasive alternatives for treating atrial fibrillation by delivering a tissue-damaging agent to selected areas of the heart. One exemplary embodiment of the invention provides a method of treating cardiac arrhythmia. This method includes positioning a distal tissue-contacting portion of a body in surface contact with a tissue surface of cardiac tissue; detecting the surface contact between the tissue-contacting portion and the tissue surface; and thereafter, injecting a tissue-ablating agent into the cardiac tissue through the tissue-contacting portion of the body.

1 . A method of treating cardiac arrhythmia comprising:
 positioning a tissue grasping member adjacent a target tissue of a vessel, the target tissue having two spaced-apart wall segments, wherein the tissue grasping member comprises at least first and second opposed tissue contacting members each having first and second tissue contacting surfaces spaced apart from one another to define a gap therebetween, and each further having a fluid delivery conduit disposed in the gap and spaced apart from the target tissue;   moving the opposed tissue contacting members of the tissue grasping member toward one another to deform the target tissue such that the wall segments are moved closer to, but remain spaced from, one another, such that blood flow through the portion of the vessel deformed by the tissue contacting members is substantially unconstricted; and   ablating target tissue in contact with the tissue contacting members to create a lesion extending through both wall segments.   
     
     
         2 . The method of  claim 1 , wherein the first and second opposed tissue contacting members are pivotally connected to one another. 
     
     
         3 . The method of  claim 1 , wherein the first tissue contacting member includes a tissue contacting face and a recess comprising a generally U-shaped channel extending along a center line of the first tissue contacting member. 
     
     
         4 . The method of  claim 3 , wherein the tissue contacting face includes a pair of sensors spaced apart from one another across the recess and configured to detect contact of the first tissue contacting member with the target tissue. 
     
     
         5 . The method of  claim 4 , wherein contact of the first tissue contacting member with the target tissue is detected by monitoring current flow between the pair of sensors. 
     
     
         6 . The method of  claim 1 , further comprising:
 delivering a treatment fluid through the fluid delivery conduit to the target tissue.   
     
     
         7 . The method of  claim 6 , wherein the treatment fluid is directed out of the fluid delivery conduit in a series of jets. 
     
     
         8 . A method of treating cardiac arrhythmia, comprising:
 juxtaposing two spaced-apart wall segments of a pulmonary vein adjacent a heart atrium along a first plane;   ablating tissue in the two spaced-apart wall segments along the first plane with an ablating member to form a first lesion along a first length of each wall segment;   after ablating tissue alone the first plane, repositioning the ablating member a first time;   juxtaposing the two spaced-apart wall segments along a second plane; and   ablating tissue in the two spaced-apart wall segments along the second plane with the ablating member to form a second lesion along a second length of each wall segment, the second length adjoining the first length.   
     
     
         9 . The method of  claim 8 , further comprising:
 after ablating tissue along the second plane, repositioning the ablating member a second time;   juxtaposing the two spaced-apart wall segments along a third plane; and   ablating tissue in the two spaced-apart wall segments along the third plane with the ablating member to form a third lesion along a third length of each wall segment.   
     
     
         10 . The method of  claim 8 , wherein the first and second lengths at least substantially circumscribe the pulmonary vein. 
     
     
         11 . The method of  claim 8 , further comprising:
 repositioning the ablating member; and   ablating tissue to form at least one additional lesion which, together with the first and second lengths, forms a series of lesions which at least substantially circumscribes the pulmonary vein.   
     
     
         12 . The method of  claim 8 , wherein the ablating member includes a first tissue contacting member, a second tissue contacting member pivotally connected to the first tissue contacting member, and a fluid delivery conduit. 
     
     
         13 . The method of  claim 12 , further comprising:
 delivering a treatment fluid through the fluid delivery conduit to the two spaced-apart wall segments.   
     
     
         14 . The method of  claim 13 , wherein the treatment fluid is directed out of the fluid delivery conduit in a series of jets. 
     
     
         15 . A method of treating cardiac arrhythmia, comprising:
 bringing opposed walls of a cardiac vessel closer together, but not in contact with one another, along a distance within a plane, such that blood flow from the cardiac vessel into a heart atrium is substantially unconstricted; and   ablating tissue in the opposing walls along the plane to form a corresponding line of ablated tissue through the opposed walls.