Electrocardiograms (EKG)

What is an EKG?

An EKG machine is a voltmeter. In other words, it reads electrical energy from the body. The heart uses electrical energy to cause muscle cells to contract. By reading the electrical energy of the heart, the nurse can tell if it is generated and conducted correctly.
An EKG is obtained by placing electrical sensors (leads) on the patient’s chest. Usually 12 leads are used to look at the heart from many angles. The EKG machine doesn’t look at all 12 leads at once; instead it chooses one at a time to view, and each view we call a lead on the resulting tracing.

Electrical impulses are transferred to paper by the EKG machine. Two components of the tracing are especially useful: time and amplitude. Time is measured horizontally across the EKG strip. Amplitude is measured by the height of the tracing, which corresponds to the strength of the electrical impulse.