Heart disease is the leading cause of death among Americans. Recently the bio-tech industry has been exploding with cardiac research like last week's heart attack preventing nanobots. New research by the team at the University of California, Berkley has created working human heart cells on a tiny chip designed to test the efficacy of new drugs in clinical trials. This heart-on-a-chip is officially known as a cardiac microphysiological system, or MPS. Using this heart-on-a-chip, scientists can measure the potential cardiac damage of a drug before it reaches expensive human trials.