Ablation system, clamp and method of use

Abstract

A method and apparatus for ablating tissue are disclosed that comprise positioning two or more bi-directional ablation energy sources in spaced-apart relation in sufficient proximity to the tissue to be ablated so that, upon activation each energy source creates an energy field in the tissue to be ablated. The energy sources are spaced such that the energy fields created by at least one of the activated sources partially overlaps with the energy field created by one or more of the other energy sources. The energy sources are alternately activated and deactivated, so that a substantially constant energy field results where the energy fields created by at least two of the energy sources overlap. While the energy sources are preferably RF energy sources, other energy sources, such as microwave, may be used.

1 . A method, comprising:
 clamping cardiac tissue between opposing jaws of an ablation clamp to apply pressure to the cardiac tissue proportional to a thickness of the cardiac tissue, wherein the jaws each comprise an electrode; and   energizing the electrodes with electric current by pulsing the electric current to form a transmural lesion in the cardiac tissue.   
     
     
         2 . The method of  claim 1 , further comprising clamping the jaws to create a jaw gap that is less than a thickness of the cardiac tissue. 
     
     
         3 . The method of  claim 1 , wherein one or more of the jaws comprise an insulator comprising a convex surface and one or more of the electrodes is centered laterally on the insulator. 
     
     
         4 . The method of  claim 1 , wherein the applied pressure is between about 10 pounds per square inch (PSI) and about 23 PSI. 
     
     
         5 . The method of  claim 1 , wherein the jaws each comprise an arcuate surface formed from one of the electrodes and an insulator and the method further comprises compressing the cardiac tissue between the arcuate surfaces to apply the pressure to the cardiac tissue. 
     
     
         6 . The method of  claim 5 , further comprising applying a highest pressure to the tissue at a narrowest gap between the arcuate surfaces. 
     
     
         7 . The method of  claim 1 , wherein respective energy fields of the electrodes resulting from the pulsing of the electric current at least partially overlap. 
     
     
         8 . The method of  claim 7 , further comprising electrically energizing the electrodes, wherein the energy fields comprise current fluxes of the electrodes. 
     
     
         9 . The method of  claim 1 , wherein the transmural lesion is formed proximate energy fields of the electrodes resulting from the pulsing of the electric current. 
     
     
         10 . The method of  claim 1 , wherein one or more of the electrodes are energized by an energy source comprising a radiofrequency, microwave, ultrasound, or laser energy source. 
     
     
         11 . The method of  claim 10 , wherein the ultrasound energy source comprises a high intensity focused ultrasound (HIFU) energy source. 
     
     
         12 . The method of  claim 1 , wherein the electrodes comprise a pair of opposed electrodes having opposite polarity. 
     
     
         13 . The method of  claim 1 , further comprises repeating the pulsing over multiple pulsing cycles. 
     
     
         14 . The method of  claim 1 , wherein one or more of the jaws comprises an insulator comprising a convex surface and one or more of the electrodes is centered laterally on the insulator.