Observing the human heart from all angles

You might think one human heart beats like another, but they’re a bit like snowflakes. No two are alike. Especially diseased hearts.

A normal human heart weighs 350-400 grams, but a diseased heart may weigh more than twice that amount. Those differences matter, whether you’re doing surgery or inventing devices to aid a stressed heart. Helping physicians and medical engineers understand and prepare for the differences among human hearts is one of the University of Minnesota’s gifts to the world.

Part of a unique 15-year partnership with Medtronic, efforts at the U of M’s Visible Heart Lab have resulted in reanimations of more than 50 human hearts and thousands of animal hearts. This process results in a live heart that functions outside the body for several hours, pumping a clear fluid instead of blood. Vital to improving cardiac care, the process enables researchers to observe the inner workings of the heart or functional anatomy.

Education + collaboration

Funding from Medtronic helped the University develop the patented system for reanimating large mammalian hearts. The results of the human heart reanimations are cataloged in the Atlas of Human Cardiac Anatomy. People come to the University from around the world to view live hearts at work, but they can also observe them via any Internet connection at no cost.

Paul Iaizzo, the lab’s director, also teaches a weeklong course in advanced cardiac physiology and anatomy each January (he’s also the course originator/director). The course features faculty and guest lecturers from across the U of M, and it’s often attended by medical device engineers from companies such as Medtronic, Boston Scientific, St. Jude and 3M.

During the class, participants dissect a human cadaver, usually one that has had a cardiac device implanted. They see how the body functions and how the implanted device impacts that body. They also view images of reanimated hearts so they can visualize how the devices they design will work. 

“The people we train are uniquely educated to go into the workforce in Minnesota,” says Iaizzo, who is also a frequent lecturer for corporations that design and manufacture cardiac devices. “We really focus on our mission of getting the best education to students and to local industry.” 

In addition to his other commitments, Iaizzo serves on the faculty of the New Product Design and Business Development Program, a collaboration of the Carlson School of Management, the College of Science and Engineering, the College of Design, and a variety of corporate sponsors. During this two-semester program, groups of students develop and complete a business plan, and create a working prototype. Perhaps due to Minnesota’s favorable cardiac device environment, almost 80 percent of these students focus on medical device development. 

“Over the last few years, our students have crafted more than 30 products related to the cardiac industry,” says Iaizzo. “This is unique across the country.” He adds that students often leave the class with internships and/or job offers as a result of their work. 

Learning from bears

A groundbreaking project at the Visible Heart Lab involves efforts to understand bear hibernation that could eventually help heart attack victims — or astronauts on long missions. Black bears are masters of hibernation, during which they starve themselves for four to six months at a time. Yet they do so without any loss of heart mass or function. “In contrast, a human who is immobilized for only two months will lose 20 to 30 percent of his or her heart mass,” explains Iaizzo. “We’re trying to understand why bears can do this and humans can’t.”

Iaizzo has been working on the project for more than 15 years. Medtronic is collaborating on the research, as is the Minnesota Department of Natural Resources. “We’re looking at certain hormones in the bear’s bloodstream. If we pretreat a heart with those chemicals and then induce a heart attack, we can reduce damage by 50 percent. We’re also looking to see if these chemicals administered immediately after a heart attack will have any benefit.”

The method has not been tested on humans yet, but the findings hold great promise for cardiac care across the globe.

Republished with permission from Business @ the U of M, a publication of the Office of Vice President for Research.

Story by Vincent Hyman, a freelance writer based in St. Paul, Minn.