Pacemakers serve an invaluable purpose, by electrically stimulating a recipient's heart in order to keep it beating at a steady rate. The implantation of a pacemaker is a major surgical procedure, however, plus its presence in the body can lead to complications such as infections. Now, for the first time, scientists have instead injected genes into the defective hearts of pigs, converting unspecialized heart cells into "biological pacemakers."

The procedure was reportedly the result of "dozens of years of research," and was carried out by a team led by Dr. Eduardo Marbán at the Cedars-Sinai Heart Institute in Los Angeles.

The pigs, all of which suffered from complete heart blocks, had the gene TBX18 injected into their hearts via what is described as a minimally invasive catheter procedure. As a Cedars-Sinai representative explained to us, this caused some of the existing unspecialized cardiac cells to transform into sinuatrial node cells. The sinuatrial node consists of tissue that initiates the electrical impulses that set the rhythm of the heart – it's essentially the heart's natural pacemaker.

The day after the procedure, the recipient pigs' hearts were already beating faster than those of a control group. That stronger heartbeat lasted for the duration of the 14-day study, indicating that the treatment could be a longer-term solution than was first thought.

Initially, Marbán and his colleagues conceived of it more as a temporary fix for patients who were having problems with their man-made pacemakers. Now, they're considering the possibility that it could be "a long-lasting biological treatment for patients." It could also be used on infants still in the womb, who can't currently receive mechanical pacemakers.

A paper on the research was published today in the journal Science Translational Medicine. Human clinical studies could begin within approximately three years.