Like any object with an electric flow, the heart generates a magnetic field. Different heart problems alter this magnetic field in different ways. For instance, some patients with irregular heartbeat need to have one of the electrical nodes in their heart cauterized. Normally, doctors need to go through a process of trial and error to determine which node needs help. Using the portable magnetometer, though, doctors can pinpoint the right node immediately, cutting the time of the corrective procedure by 80 percent.