While deaths from heart attacks are down, the rate of complications such as congestive heart failure and irregular heartbeats is on the rise, simply because more people are surviving what might once have been fatal heart attacks.

But they are left with damaged hearts.

What if doctors could place a patch of healthy cells over areas of heart damage?

Researchers from three institutions — the University of Wisconsin-Madison, the University of Alabama at Birmingham, and Duke University — have teamed up to test three-dimensional “heart patches” in animal trials, the last big hurdle before conducting studies in human patients.

In theory, the heart patches — which are engineered tissue composed of the several different types of cells that make up heart muscle — could be implanted to replace diseased or damaged tissue.

They would then perform all the functions of healthy, beating heart muscle.

Treating diseased hearts by implanting lab-grown cells to replace damaged tissue has been an aspiration of stem cell biologists ever since all-purpose human stem cells were first derived and cultured at UW-Madison nearly 20 years ago.

This trial was part of an $8.6 million project funded by the National Institutes of Health.

Other types of cells have been experimented on for cardiac repair, but have shown limited success. Advances in stem cell technologies have brought more precision to the problem.

Scientists now have the ability to make in the lab all of the specific cell types that constitute heart muscle. That could even allow cells to be personalized for individual patients.