http://goo.gl/DPyT8 : You might have watched television shows or movies where a patient in a hospital is attached to an electrocardiogram (ECG). You might recognize it as the machine with a line moving across a screen that occasionally spikes (or remains flat when a patient is dying). This machine can measure the electricity going through a patient’s heart. A doctor can use the information to know when a patient is having heart rhythm problems or even a heart attack.