Modular pulsed pressure device for the transport of liquid cryogen to a cryoprobe

A cryogenic system for use in treating cardiovascular disease comprising:

• i) a cryoengine comprising:
• a) a dewar that can be filled with cryogen;
• b) a first cartridge subassembly comprising a first cryogen supply cylinder linked to a first cryogen pressurization cartridge, one or more first heaters, and a first cartridge subassembly venting valve, wherein (i) said first cryogen supply cylinder is positioned to be immersed in the cryogen when the dewar is filled with the cryogen and (ii) said first cryogen pressurization cartridge is positioned outside of the dewar;
• c) a second cartridge subassembly comprising a second cryogen supply cylinder linked to a second cryogen pressurization cartridge, one or more second heaters, and a second cartridge subassembly venting valve, wherein (i) said second cryogen supply cylinder is positioned to be immersed in the cryogen when the dewar is filled with the cryogen and (ii) said second cryogen pressurization cartridge is positioned outside of the dewar;
• and
• d) an immersible cryogen pump positioned to be immersed in the cryogen when the dewar is filled with the cryogen;
• ii) a cryoprobe or a cryocatheter positioned outside said dewar and adapted for insertion into a body at the heart for ablating cardiac tissue;
• iii) at least one supply line connected to said cryoengine and to said cryoprobe or cryocatheter and configured to deliver cryogen from the first cartridge subassembly or the second cartridge subassembly to said cryoprobe or said cryocatheter;
• and
• iv) at least one return line connected to said cryoprobe or cryocatheter and to configured to deliver the cryogen from said cryoprobe or said cryocatheter to said dewar;
• wherein said cryogenic system is configured so that when the dewar is filled with the cryogen, the cryogenic system operates as follows:
• (A) activation of the immersible cryogen pump sequentially fills the first cartridge subassembly and the second cartridge subassembly with cryogen, wherein said first cartridge subassembly venting valve allows gas to be vented from said first cartridge subassembly during filling of said first cartridge subassembly, and said second cartridge subassembly vent valve allows gas to be vented from said second cartridge subassembly during filling of said second cartridge subassembly;
• (B) activation of said one or more first or second heaters generates pressure in the first cartridge subassembly or the second cartridge subassembly to convert the cryogen to supercritical cryogen, wherein the cryogen converted to the supercritical cryogen is in the first cryogen supply cylinder that is immersed in the cryogen in said dewar or in the second cryogen supply cylinder that is immersed in the cryogen in said dewar, wherein said supercritical cryogen in said first cryogen supply cylinder and in said second cryogen supply cylinder, which are immersed in the cryogen in the dewar, becomes subcooled, and said subcooled supercritical cryogen can be delivered from said first cartridge subassembly to said cryoprobe or cryocatheter and returned to the dewar, and
• (C) upon emptying of said subcooled supercritical cryogen from said first cartridge subassembly, said cryoengine is configured to deliver subcooled supercritical cryogen from said second cartridge subassembly to said cryoprobe or cryocatheter and said cryogen is returned from cryoprobe or cryocatheter to the dewar.