What information is in an electrocardiogram?

Electrocardiogram's (EKG or ECG) represent a depiction of the electrical events in the myocardium that make mechanical events take place. EKG's contain waves and wave forms. Each wave on the EKG tracing tells a story of a mechanical action that the heart is taking. EKG's are "12 lead", a lead is a different view from a different angle. It's like taking a photo from a different position or angle.

The normal waveforms are P,QRS, and T. The P wave represents depolarization of the atria. The QRS complex represents depolarization of the ventricles. The T wave represents repolarization(re  not de) of the ventricular walls.

Other wave forms exist, but are abnormal, and represent disease or ischemia in the muscle. It is important for students to realize that in order to recognize something that is Abnormal, they first must be able to recognize the Normal waveforms.