Electrocardiogram Readings

The readings below are from a "12 lead ECG". A "lead" is an electrical picture. The lead is generated from wires which are placed on the limbs and across the chest. Usually ten wires are used for a 12 lead ECG. Each wire records the same electrical impluse, but from a different position in relation to the heart.

When reading an ECG, a physician will note the elevations and depressions of the three segments of the heart beat. The first reading is of a normal, undamaged heart. The second reading is considered abnormal, due to abnormalities in the ST segment.