What are artifacts in the context of an electrocardiogram?

Artifacts in an electrocardiogram (EKG) refer to misleading signals that are not a true reflection of the heart's electrical activity. Interference picked up by the ECG machine is considered a type of artifact, as it can obscure or distort the true signals being recorded. This interference can come from various sources, such as electrical devices, muscle activity, or poor electrode contact, all of which can make the recorded EKG look abnormal.

The other options represent different phenomena related to the heart or EKG interpretation. Baseline drift refers to a gradual upward or downward movement of the baseline on the EKG due to issues like patient movement or respiration but does not encompass the broader scope of artifacts. False heartbeats are not a standard term used in EKG terminology and might refer to misinterpretation of the signals, while extrasystoles are actual premature heartbeats, indicating a heart that is functioning, albeit with irregularities, rather than artifacts that interfere with the proper reading of heart signals. Thus, interference picked up by the ECG machine is the most accurate representation of artifacts in this context.