Every heart beat is associated with generation of a weak electrical current within the heart. This current is recorded through sensitive electrodes that can be externally attached to the skin of the chest and extremities. The EKG recorder is then amplifying this current and recording it as a tracing on paper, producing the so-called electrocardiogram (EKG).
From the recorded EKG certain heart problems can be identified. An acute or old myocardial (Heart attack), actual myocardial ischemia (lack of blood supply to the heart) and cardiac rhythm disturbances are the most important abnormalities that may be identified in the resting EKG.