Johns Hopkins researchers have found evidence that genetically engineered heart cells derived from human embryonic stem (ES) cells might one day be a biological alternative to the electronic pacemakers used by hundreds of thousands of people worldwide.

Human ES cells were grown in the lab and encouraged to become heart cells. The researchers then selected clusters of the cells that beat on their own accord, indicating the presence of pacemaking cells. These clusters triggered the unified beating of heart muscle cells taken from rats, and, when implanted into the hearts of guinea pigs, triggered regular beating of the heart itself.

These implanted cells also responded appropriately to drugs used to slow or speed the heart rate, which electronic pacemakers can’t do.

Johns Hopkins Medicine news release