Catheter for ice mapping and ablation

A catheter for ice mapping and ablation having a proximal end and a distal end, said catheter comprising:

• a first lumen for permitting passage of an electrically conductive cooling fluid from said proximal end to said distal end;
• a second lumen permitting return of said cooling fluid from said distal end to said proximal end;
• an ablation means located near said distal end of said catheter for ablating myocardial tissue;
• and
• an electrocardiographic mapping means comprising at least one mapping electrode located near said distal end of said catheter, said electrocardiographic mapping means comprising at least one mapping electrode and wherein said cooling fluid is electrically conductive.

A catheter for ice mapping and ablation having a proximal end and a distal end, said catheter comprising:

• a first lumen for permitting passage of a cooling fluid from said proximal end to said distal end;
• a second lumen permitting return of said cooling fluid from said distal end to said proximal end;
• an ablation means located near said distal end of said catheter for ablating myocardial tissue;
• and
• an expansion chamber located substantially at said distal end of said catheter, and
• wherein said cooling fluid is a pressurized gas which becomes cold upon expansion in an expansion chamber.

A method of cryoablation comprising the steps of:

• introducing an ice mapping and ablation catheter into a cardiac blood vessel, said ice mapping and ablation catheter having a proximal end and a distal end, said ice mapping and ablation catheter comprising:
• a first lumen for permitting passage of a cooling fluid from said proximal end to said distal end;
• a second lumen permitting return of said cooling fluid from said distal end to said proximal end;
• an ablation means for ablating cardiac tissue;
• positioning said distal end of said catheter at a proposed lesion site;
• introducing a cooling fluid into said first lumen to cool said distal end and thereby cool said proposed lesion site to approximately +5 degrees Celsius;
• testing said proposed lesion site for electrical activity using electrocardiographic mapping means;
• evaluating results of said test to confirm effectiveness of said proposed lesion site;
• and
• generating a lesion by ablating said region with said ablation means.

A catheter for ice mapping and ablation comprising:

• an open proximal end adapted for connection to a reservoir containing a cooling fluid;
• a closed, thermally conductive distal end;
• a first lumen conducting said cooling fluid from said proximal end to said distal end to chill cardiac tissue for suppression of localized electrical activity;
• a second lumen permitting return of said cooling fluid from said distal end to said proximal end;
• a first electrode located near said distal end of said catheter, wherein said first electrode is a first pole of an electrocardiographic mapping means;
• a second electrode located at said distal end of said catheter, wherein said second electrode is a second pole of said electrocardiographic mapping means and a radio frequency ablation means operative to transmit electric current form said first radio frequency electrode to a second radio frequency electrode separated from said first radio frequency electrode by tissue including tissue to be ablated;
• a position stabilization means including at least one surface section on said distal end adapted to prevent slippage of said distal end when said distal end is in contact with said tissue to be ablated;
• and
• a steering means to position said radio frequency ablation means.