Edwards Lifesciences (NYSE:EW) wants a federal judge to rule that a pair of patents owned by arch-rival Medtronic (NYSE:MDT) are invalid because they aren’t specific enough.

The patents – the so-called ‘741 patent for a "Method and system for nerve stimulation and cardiac sensing prior to and during a medical procedure" and the ‘829 patent for a "Method and system for nerve stimulation prior to and during a medical procedure – cover nerve stimulation technology.

Edwards and Medtronic have spent considerable time in courts around the world, each arguing that the other’s transcatheter aortic valve implant infringes various patents. Medtronic acquired the beef along with CoreValve in a $700 million buyout in April 2009.

Last week a court in Germany ruled that the CoreValve TAVI infringes an Edwards Lifesciences patent, forcing it to cede the German market to Edwards and its Sapien valve.

Now Edwards is asking Judge James Selna of the U.S. District Court for Central California to declare the ‘741 and ‘829 patents invalid because they fail to specify certain crucial elements of the technology, according to court documents.

"This motion is made on the grounds that (1) the accused procedures do not meet the ‘tubular structure’ requirement of U.S. Patent No. 8,036,741 (the ”741 patent’); and (2) the accused procedures do not meet the ‘stimulation stops or slows cardiac rhythm’ requirement of U.S. Patent No. 7,184,829 (the ”829 patent’)." according to the documents.