US 6,981,382 B2
Distal end for cryoablation catheters
David J. Lentz, La Jolla, Calif. (US); Matt M. Riordan, Saratoga, Calif. (US); and Eric Ryba, San Diego, Calif. (US)
Assigned to CryoCor, Inc., San Diego, Calif. (US)
Filed on Jul. 24, 2003, as Appl. No. 10/626,887.
Prior Publication US 2005/0016188 A1, Jan. 27, 2005
Int. Cl. F25D 15/00 (2006.01); A61B 18/02 (2006.01)
U.S. Cl. 62—119 16 Claims
OG exemplary drawing
 
1. A heat transfer system which comprises:
a hollow supply tube having a proximal end and a distal end;
a capillary tube having a proximal end and a distal end with the proximal end thereof connected in fluid communication with the distal end of said supply tube, said capillary tube being formed with a lumen having a length “l” and a diameter “d”;
a tip member positioned to surround the distal end of said capillary tube to create a cryo-chamber therebetween; and
a source of refrigerant fluid connected in fluid communication with the proximal end of the supply tube to introduce the refrigerant fluid into the supply tube wherein said fluid refrigerant has been pre-cooled to approximately −45° C. at a working pressure “pw” of approximately 400 psia for transfer of the refrigerant fluid through said supply tube and through said capillary tube for exit from the distal end of said capillary tube and into said cryo-chamber in a substantially liquid state for transition of the refrigerant fluid into a gaseous state with a tip pressure “pt” and a tip temperature “Tt” for heat transfer through said tip member and into the gaseous fluid refrigerant in said cryo-chamber;
wherein an aspect ratio “d/l” for the capillary tube is in a range of 0.0008 to 0.0017.