InnerPulse announced Monday it has raised $50 million in private financing to continue developing an implanted device that jump-starts a heart that has stopped beating.

That may be the single largest infusion of private cash for a medical device company in North Carolina, said Emily Mendell of the Arlington, Va.-based National Venture Capital Association.

The money came from six venture-capital and medical firms and brings InnerPulse's funding to $85 million since the small Research Triangle Park company was formed in 2003.

The money is expected to last three years, which is when the company expects its defibrillator will be on the market in Europe, said chief executive Daniel Pelak.

A defibrillator revives a heart when it is fibrillating, or quivering, instead of beating rhythmically. The InnerPulse defibrillator would be implanted like a pacemaker and would deliver an electrical shock when the heart stops beating.

The investors backing InnerPulse think the device will tap into a growing market of baby boomers. That includes 384,000 heart attack survivors in this country every year who would be candidates for the InnerPulse defibrillator.

"The demographics are moving in that direction," said John Maroney, a general partner with Delphi Ventures in Menlo Park, Calif., which participated in the financing.

The InnerPulse device is designed to be simple enough to be implanted through patients' legs by a cardiologist. That would give the device an edge over older defibrillators that require chest surgery by a specialist.

InnerPulse has tested the defibrillator on pigs and dogs and plans to test it on 50 to 100 people this year in Germany.

The company wants to begin selling the device in Europe in 2009. As part of the process, InnerPulse will have to win European approval for its defibrillator manufacturing facility in RTP. The implant would come to market in the U.S. sometime after that.

The defibrillator under development resembles a 30-inch segment of cable or catheter and is about the thickness of a pencil. Defibrillators on the market now are shaped like a hockey puck.

The InnerPulse device is powered by batteries that will last up to five years, at which point the mechanism would be removed and replaced. InnerPulse is perfecting the coating of the device as well as eight connectors that give it flexibility inside the body.

The company employs 35 people and is looking to hire 15 to 20 more, mostly engineers.

InnerPulse CEO Pelak said the biggest challenge is finding qualified engineers in a very specialized field. The defibrillator industry is clustered in Minneapolis and California, where the major defibrillator developers are based: Medtronic in Minneapolis and St. Jude Medical in Minneapolis and California.

"I wind up being an economic developer for the Triangle trying to get people to move here," Pelak said. "One of the things that you hear is, 'I wind up moving to Research Triangle Park and there's not a lot of medical device companies there. If I have to find another job, where would I go?' "