Method of tracing the electric current of a heartbeat to provide information on the heart .
Electrocardiograms (ECGs) are made by applying electrode s, usually to the arms, legs, and chest wall, attached to an electrocardiograph, which records the tiny heart current. Upward and downward movements on the tracing reflect contractions of the atria and ventricles. Deviations from a standard point to a possible heart disorder and its site, as well as to possible high blood pressure and other diseases.