Honing the Edge

Idea man: 270 patents

  • Article by: THOMAS LEE , Star Tribune
  • Updated: March 24, 2011 - 9:10 AM

Minnesota's most prolific inventor -- creator of a stopwatch-sized ICD and much, much more -- just keeps tinkering.


Mark Kroll sits on the deck of his home overlooking Lake Minnetonka. Kroll holds 270 patents, most in the medical science field.

Photo: Glen Stubbe, Star Tribune

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Mark Kroll is running out of time.

The man who is already the state's most prolific inventor wants to keep pumping out patents before the Grim Reaper ultimately arrives at the door.

"You got things in your brain, and if you die with them left in there, it's a waste," said the 55-year-old inventor, a tall, boyish-looking man who often takes several seconds to ponder a question before answering. "I want to get out what little I have left in my brain before I expire."

Kroll has already gotten plenty out of his brain. He holds more than 270 patents, tops in Minnesota and second in the world for medical devices. Some of his work has led to impressive breakthroughs in cardiovascular technology.

Kroll, a former top executive at St. Jude Medical Inc. who specializes in electric physiology, developed ways to shrink implantable cardioverter defibrillators (ICDs). Such devices, now also sold by major companies including Medtronic, Boston Scientific and Johnson & Johnson, shock an errantly beating heart back into rhythm.

Other ideas are less profound: A life vest that allows tanning. A phone for pets. But Kroll's brain keeps turning and so do the patents.

"He's the guru," said Brad Pedersen, a partner with Patterson, Thuente, Skaar & Christensen, a Minneapolis-based law firm that specializes in patent law. "I'm just the grasshopper learning at the feet of the master."

All in the family

Growing up in Venezuela and Minnetonka, Kroll learned at the feet of his own master, his father, William. The elder Kroll studied electrical engineering, spoke 10 languages, discovered a tribe in Brazil that had not been influenced by Western civilization, and mastered acoustic technology.

Some of William Kroll's sound and vibration-prevention work can be found in the University of Minnesota's West Bank Union performance hall, Mayo Auditorium in Rochester and St. David's Episcopal Church in Minnetonka.

William Kroll also was an accomplished inventor, earning patents for an electric cigarette lighter and hot plate. He invented an electronic method to weigh objects in motion that defy use of a scale. The father's work formed the basis of a business Mark Kroll and three siblings founded in 1979 called Intercomp Co., now a leading manufacturer of scales used to weigh aircraft from jet fighters to the space shuttle.

Of William Kroll's eight children, five are inventors who hold patents. Mark, the oldest, stood out, said brother Fritz Kroll, a sales agent with Edina Realty in Minneapolis.

"We always thought of him as the brain," Fritz Kroll said. "Mark was always willing to try anything, do stuff a bit differently."

He recalled watching a home video in which Mark was riding a motorcycle with one leg in the air and a cat on the gas tank.

Why did Mark do that?

"Just a sunny day," Fritz Kroll said.

Mark Kroll said he got interested in medicine after reading an article in the ninth grade about the world's first heart transplant.

"It really inspired me," Kroll said. "I naively and arrogantly thought that with modern medical technology we could achieve eternity. Just fix things that broke."

While studying mathematics at University of Minnesota in the early 1970s, Kroll worked as a research aide at Medtronic. Twenty years later, Kroll made perhaps his greatest contribution to the medical device industry.

At the time, ICDs were bulky devices -- the size of two cigarette packs. Doctors seldom used them because they were difficult to implant. By manipulating the electrical impulses the ICD delivered to the heart, Kroll discovered that a smaller device could transmit the same amount of energy in a more efficient way.

As a result, manufacturers could shrink the ICD to about the size of a stopwatch, allowing doctors to implant the device under the collarbone instead of near the stomach. Kroll, then a vice president of research at Angeion Corp., earned 72 patents alone for this work, not to mention $60 million in licensing revenue for his employer.

Outside the box

Kroll's technology helped popularize the device and transform the ICD into a $5 billion global market, said David Adinolfi, a former president of St. Jude Medical's Daig division, which is responsible for interventional cardiology and electric physiology. Today, every ICD carries some technology invented by Kroll, he said.

"He is the epitome of 'thinking outside of the box,'" Adinolfi said. "He looks at different ways to see the problem. Engineers use pure logic to solve problems through a process. Mark would ask: 'What is the problem we are trying to solve?'"

After serving as chief technology officer and senior vice president at St. Jude Medical's Cardiac Rhythm Management Division, Kroll retired in 2005. But he admits that retirement is an illusion.

Kroll serves on several company boards, including Taser Inc., where he has staunchly defended the company against charges that the electric weapon, which police use to subdue suspects, can be fatal.

"We all want answers and we all want to blame something," Kroll wrote in a report last year. "In the 1990s, in-custody deaths were blamed on pepper spray. Today, Taser devices are being seen as a simple, 'obvious' scapegoat for these tragic deaths."

Kroll is fond of start-ups. He's especially excited about two companies where he's on the board: Galvani, developing an "electric CPR" device and OncoStim, using low-level electricity to kill cancerous tumors in a way that stimulates the body's immune system to attack other cancerous cells.

"It seems like a very good fit to have someone with technical knowledge on the board," said David Land, president of Medisyn Technologies Inc., a Minnetonka-based start-up that is using advanced mathematics to speed the development of drugs. "You look for someone who has done something very well. Mark is well-decorated with all of his patents. Plus, he is well-connected" with investors.

Disciplined and competitive

Kroll, though, remains an inventor at heart. He says that most people can be inventors; what's needed is a little initiative.

"You can actually teach inventing," Kroll said. "It's mostly attitude. Someone who works hard at it can do quite well. My wife [Lori] is far more creative than me but I have more patents. She has six. But I get paid to write patents. I made it a priority and she didn't."

Pedersen, the patent lawyer, said Kroll excels at applying his inventions to other uses and then generating additional patents for that work.

"We all have spurts of creativity," he said. "I think Mark is just very disciplined about it. He has the self-discipline to optimize that innovation."

Kroll admits that he is competitive about filing patents. He ticks off rankings as if reading the back of the sports page: No. 1 patent holder from Minnesota; No. 1 in implantable medical devices, and No. 2 in the world for all medical devices. Or as his children, Brady, Mollie, Ryan and Chase, say: "first loser in medical devices."

That's only temporary. Trailing the leader, Californian Felix Theeuwes, by just three patents, Kroll figures he'll grab the top spot at the end of the summer.

"If I can be the top home run hitter in one year in professional baseball, I would be pretty happy and not worry about it again," he said. "I don't have any groupies."

But there is one number that's likely beyond Kroll's reach: an inventor in Japan has around 1,000 patents.

"I'm not going to catch him," Kroll said.

Thomas Lee • 612-673-7744

Over the coming weeks, Honing the Edge will profile four people whose skills and backgrounds are needed to launch a successful start-up: the Inventor, the Entrepreneur, the Venture Capitalist and the CEO. Today, we look at Mark Kroll, one of the country's most prolific inventors of medical devices.

  • about this series

  • A continuing series on innovation in Minnesota.
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