Betterhumans reports on a new study in rats that shows "embryonic stem cells can repair heart tissue and speed recovery after heart attack." This is not too surprising, since effective adult stem cell heart therapies have already been demonstrated. The embryonic stem cell therapy would seem to be superior, however: "The stem cells transformed into heart cells and integrated with the surrounding muscle. Within three weeks, the researchers saw improved heart function and reduced scarring compared to a control group of animals that didn't receive the stem cells. Moreover, the response to stress was superior in the stem cell-treated hearts, and there were no deaths or evidence of abnormal heart rhythms."