Which of the following is NOT one of the common artifacts seen in EKG readings?

Normal sinus rhythm is considered the correct response because it represents a regular and expected heart rhythm, characterized by the presence of a P wave, a consistent PR interval, a normal QRS duration, and a heart rate typically between 60 and 100 beats per minute. It does not indicate any abnormality or artifact in the EKG tracing.

In contrast, interrupted baseline, electrical interference, and baseline wander are all types of artifacts that can appear on an EKG. An interrupted baseline often results from a loose lead or poor electrode contact, which makes it difficult to interpret the heart's activity. Electrical interference can occur from other electronic devices nearby, producing extraneous signals on the EKG. Baseline wander is typically caused by patient movement or respiratory variations, leading to undulating shifts in the baseline of the EKG tracing. These artifacts can obscure the true cardiac signal and complicate diagnosis. Therefore, normal sinus rhythm does not fall into the category of artifacts, as it is the standard, healthy rhythm expected from a functioning heart.