When a patient has a heart attack, parts of the heart can be left scarred. While a normal heart can conduct electricity throughout the organ, electrical signals cannot travel well through the scarred portion of a damaged heart. Researchers at the Texas Heart Institute and Rice University are working to use carbon nanotubes to allow scarred heart tissue to conduct electricity again.

In order to restore the electrical flow through the heart, a material needs to have a couple of properties. First, it needs to conduct electricity itself; the materials used to sew common surgical stitches can’t conduct electricity and won’t work. Second, it needs to be able to withstand bending and relaxing many thousands of times a day as the heart beats. Metals, although they conduct electricity well, won’t withstand bending and relaxing. The researchers settled on carbon nanotubes, which are cylindrical tubes made out of pure carbon.

The team sewed carbon nanotubes into damaged portions of the hearts of both rats and sheep. They found that the carbon nanotubes improved the flow of electricity through the hearts compared to animals who received stitches with traditional surgical material. After a month, the improved electrical conduction was still present in the rat’s hearts as long as a pacemaker was also used. To test for safety, the researchers injected solutions of the carbon nanotubes into mice and into samples of human blood that had been donated by volunteers. They were not able to detect any signs of toxicity over the course of a month.

The carbon nanotubes have a long way to go before becoming a standard human treatment. This study only looked at a handful of animals for less than a month. Medical technologies often perform differently once they’ve been tested in larger samples, longer periods of time, or in human patients. If they do one day prove successful in human patients, next steps involve the design and implantation of the carbon nanotubes as well as interfacing them with pacemakers for long term use. In the meantime, carbon nanotubes represent a potential new option for treating heart disease by directly repairing damaged electric conduction in scarred tissue.

Managing Correspondent: Emily Kerr

Press article: Carbon nanotube fibres rewire damaged hearts

Scientific Article: In Vivo Restoration of Myocardial Conduction With Carbon Nanotube Fibers

Image Credit: Denise Chan: Painting of a Heart