CryoCor (San Diego, California) said it has initiated its first U.S. multi-center pivotal clinical trial under a protocol approved by the FDA to treat atrial flutter with its CryoCor Cardiac Cryoablation System. CryoCor’s system is the first cryoablation device to be entered into a clinical pivotal trial in the U.S. for the treatment of atrial flutter, one of the leading causes of hospitalization due to rapid heart rhythm, the company said.