Wired reports on progress towards growing heart tissue for regenerative therapies: "The scientists used a pacemaker to produce electric signals that mimicked a heartbeat. The electrical stimulation was a key ingredient in growing the heart tissue quickly and getting all the cells to beat in unison, according to the researchers. They bathed the heart patch in a medium of nutrients and gases to keep it pumping, and eight days later, the cells developed into tissue similar to that of the native heart." Tissue engineering is moving forward. We're not there yet, but technology to repair age-damaged hearts is certainly high on the list of things scientists would like to develop.