A federal court jury in Delaware on Wednesday ruled that Medtronic Inc.’s CoreValve System infringed on a patent of Edwards Lifesciences Corp. and held it liable for $393.6 million in damages.

The two companies are the biggest players in the European market for transcatheter aortic valves, used to treat a narrowing of the aortic valve in the heart. Medtronic is waiting to join Edwards in the U.S. market.

But they have squared off in courts in both places over patents held by Irvine, Calif.-based Edwards. The one involved in Wednesday’s ruling is known as the Cribier patent, one that also came up in Europe.

Fridley-based Medtronic said it intends to appeal the Delaware jury’s decision, which said the company’s infringement was “willful.” If that “willful” finding stands, the California company could be entitled to damages up to three times the jury’s award, plus attorneys’ fees. Medtronic said Wednesday that the final amount of damages will likely be reduced by $40 million because of overlap with another patent case.

“While we are disappointed in the jury’s verdict, we continue to believe that this decision will be overturned on appeal,” said Neil Ayotte, vice president and acting general counsel at Medtronic. “Medtronic has prevailed against Edwards in several legal actions related to a European counterpart to this patent and others, and believes the Federal Circuit Court of Appeals will find no merit to Edwards’ infringement claim. Today’s jury verdict does not impose an injunction, and Medtronic will oppose any requests for an injunction by Edwards.”

In a statement on its website, Edwards said it would seek an injunction to prohibit Medtronic from selling Core­Valve. But, in a note to investors, Leerink Swann analyst Danielle Antalffy said that such a step was “highly unlikely,” given that it was not part of Monday’s jury decision. Rather than injunctions, many U.S. patent cases involving medical devices are settled with payment of a royalty.

“Today’s ruling is a nice turn of events for [Edwards], but don’t expect investors to ascribe significant value to the ruling given that: 1) the appeals process can take time — we estimate 14-18 months,” Antalffy wrote.

Medtronic has anticipated U.S. regulatory approval of CoreValve for extreme risk patients by the end of its 2014 fiscal year, with sales in the United States to soon follow. That is expected to happen by the end of April.

In November, Medtronic resumed selling CoreValve in Germany after a court overturned an earlier ruling that Medtronic infringed on an Edwards patent. A higher court said it would not enforce that ruling, after the European Patent Office said Edwards’ patent is not valid.

Edwards’ Sapien transcatheter aortic valve is currently the only such valve approved for use in the United States, and only for patients considered at extreme risk for open-heart surgery.

Aortic valve stenosis is a deadly narrowing of the aortic valve that obstructs blood flow from the heart. Half of those patients with aortic valve stenosis die within two years of diagnosis. An estimated 150,000 patients are diagnosed with aortic stenosis each year. About one-third to one-half of those patients do not get surgery.

Some patients are considered too sick to endure the trauma of having their chests cracked open. Transcatheter aortic valve replacement allows doctors to insert a new valve into the heart by snaking a catheter up into the patient through an artery in the leg or through an incision in the upper body. Patients can be home from the hospital within a couple of days, instead of weeks after the procedure.