As it pertains to an EKG/ECG, an “artifact” is an erratic, often jagged segment of the tracing of cardiac cycles. Artifacts make interpreting EKGs more difficult because the subtle nuances of some of the smaller waves (P, Q, S and T) are often lost in the irregular lines an artifact creates.
A person moving while taking an EKG reading can cause artifacts (such as when exercising while wearing an event monitor), because movement of all muscles in your body is preceded by an electrochemical pulse, and this electrical activity is picked up through the EKG leads just as the electrical activity of the heart is.
If the heart’s electrical signal does not adequately conduct through the skin to the EKG, artifacts may also be the result. Poor skin/lead contact and sweating are just two of the reasons why the electrical signal may not conduct clearly enough.
In the EKG at the top right (click to enlarge), artifacts from an event monitor can be seen as jagged, erratic lines that make interpreting all but the R wave difficult.
