The human heart beats almost 75 times per minute or more than four million beats per year. In chemical engineering faculty member Elizabeth Lipke’s lab, hearts that have lost their rhythm are getting a jump start. Lipke is using induced-pluripotent stem cells to grow heart tissue that responds to electrical pulses, just like a beating heart. By engineering polymers that guide these cells to become specialized heart cells called cardiomyocytes, Lipke’s team can form new engineered cardiac tissues that respond in the same way as existing heart tissue. These new tissues can also be used outside of the body to test pharmaceuticals and their potential to produce dangerous side effects such as cardiac arrhythmias. For a grandmother who suffered a heart attack or a child with a genetic hole in his heart, Lipke’s work with engineered cardiac tissue is offering unhealthy hearts the chance to heal.