Ablation catheter with dedicated fluid paths and needle centering insert

A catheter comprising:

• an elongated catheter body;
• a distal tip section having a tip electrode with a distal end, the tip electrode having a needle channel and a needle centering insert, the needle centering insert having a needle passage and being positioned in the needle channel of the tip electrode;
• a needle electrode assembly having a proximal portion extending through at least a lumen in the elongated catheter body and a distal portion extending through the needle passage of the needle centering insert, the needle electrode assembly being longitudinally movable relative to the catheter body and distal tip section into an extended position and a retracted position;
• an injection control handle proximal of the catheter body configured to move the needle electrode assembly into the extended position and the retracted position;
• a fluid path B extending through at least the catheter body and having a distal exit at the distal end of the tip electrode;
• and
• a fluid path A extending through at least the catheter body and having a distal exit at a distal end of the needle electrode assembly,
• wherein the fluid path B and the fluid path A are isolated from each other,
• wherein the needle passage has an inner surface with at least one groove configured for fluid flow between the needle centering insert and the distal portion of the needle electrode assembly extending through the needle passage,
• wherein the needle centering insert is configured to guide the distal portion of the needle electrode assembly, and
• wherein the fluid path B has a proximal portion that extends through the needle electrode assembly, a distal portion that extends between the needle electrode assembly and a guide tube surrounding the needle electrode assembly, and a mid-portion that connects the proximal portion and the distal portion and traverses a side wall of the needle electrode assembly.