Irrigated ablation catheter with contact force sensing mechanism

A system for measuring contact force between a catheter and tissue in a body, the system comprising:

• a catheter, comprising:
• an elongate deformable shaft having a proximal end and a distal end;
• an inner tip member projecting outwardly from the distal end of said shaft, said inner tip member defining a fluid delivery lumen extending therethrough;
• an outer tip member coupled to said distal end of said shaft and disposed about said inner tip member, an inner surface of said outer tip member and an outer surface of said inner tip member defining a gap therebetween in fluid communication with, and configured to receive fluid from, said fluid delivery lumen, wherein said outer and inner tip members are configured such that a size of said gap varies in response to contact of said outer tip member with an external surface;
• a first fluid sensing tube defining a first port upstream from said gap;
• and,
• a second fluid sensing tube defining a second port downstream from said gap;
• and,
• a pressure sensor generating a signal indicative of a difference in fluid pressure between said first and second ports;
• wherein said pressure sensor is configured to transmit said signal to an electronic control unit configured to determine a contact force between said catheter and said tissue responsive to said signal.