Medical device

A medical device comprising:

• a tubular member extending along a longitudinal axis from a proximal end to a distal end, a top side of the tubular member including an open window disposed at the distal end;
• a first electrode disposed at the distal end of the tubular member and surrounding the open window of the tubular member or its neighboring region;
• an insulation zone surrounding the first electrode;
• and
• a second electrode surrounding the insulation zone, the second electrode including an expanded head portion on a bottom side of the tubular member.

A medical device comprising:

• a tubular member extending along a longitudinal axis from an open proximal end to a closed distal end, the tubular member including an open window disposed at the distal end;
• a first electrode surrounding the open window of the tubular member or its neighboring region;
• an insulation zone surrounding the first electrode;
• and
• a second electrode surrounding the insulation zone, the second electrode including an expanded conductive area on a side of the tubular member opposite to the open window.

A medical device comprising:

• an outer tubular member extending along a longitudinal axis from a proximal end to a distal end, the outer tubular member including an open window disposed at the distal end;
• an inner tubular member configured to be received within the outer tubular member;
• a first electrode disposed at the distal end of the outer tubular member and surrounding the open window of the outer tubular member or its neighboring region;
• an insulation zone surrounding the first electrode;
• and
• a second electrode surrounding the insulation zone;
• wherein the second electrode surrounds the insulation zone by connecting bifurcated segments of the second electrode at a location proximal to the open window.