EKG Artifacts vs Real Rhythms: How to Tell the Difference

Learn to distinguish common EKG artifacts from true arrhythmias. Motion, 60Hz interference, loose leads, and respiratory baseline wander — and what to do about each.

The Artifact Problem Here is a number that might surprise you: some studies estimate that up to 90 percent of critical rhythm alarms on telemetry floors are false positives. The vast majority of those false alarms are caused by artifact — electrical signals on the EKG tracing that come from something other than the patient's heart. As a monitor tech sitting at the central station, artifact will be a constant companion. It will wake you up at night, it will trigger alarms during shift change, and it will occasionally make a perfectly healthy patient's rhythm look like they are in cardiac arrest. Learning to tell the difference between artifact and real rhythm changes is one of the most practical skills you will develop. This is not about becoming complacent. It is about becoming accurate. The tech who calls a code for every motion artifact loses credibility, and eventually the nursing staff starts to tune out all notifications. The tech who can confidently say "that is motion artifact in Lead II, the rhythm is unchanged in V1" is the one the entire floor trusts. The Four Most Common Artifact Types 1. Motion Artifact (Muscle Tremor and Patient Movement) What it looks like: Irregular, jagged, high-frequency deflections superimposed on the baseline rhythm. During significant movement — a patient sitting up, reaching for the call bell, brushing teeth — the tracing can become completely obscured by rapid, chaotic oscillations. What it mimics: Motion artifact is the number one mimic of ventricular fibrillation. When a patient is shivering, having a seizure, or simply moving in bed, the resulting tracing can look frighteningly similar to VFib. It can also create the appearance of wide complex tachycardia, mimicking ventricular tachycardia. How to tell the difference: Look underneath the noise. In most motion artifact, you can still see QRS complexes poking through the chaos if you look carefully. True VFib has no organized QRS activity whatsoever. Also check a second lead — motion artifact often affects one lead more than others depending on which electrode the movement is near, while true VFib appears in every lead simultaneously. The toothbrush test: This is a classic training scenario. A patient brushing their teeth with an electric toothbrush produces rapid, regular oscillations that look remarkably like VFib on the monitor. The giveaway is regularity — the oscillations are too uniform, too mechanical. Real VFib is chaotic. And if you check a second lead, you will typically see a normal rhythm underneath. 2. 60-Hertz (AC) Interference What it looks like: A thick, fuzzy baseline that makes the tracing appear blurry or hazy. Instead of a clean, thin line between beats, you see a dense band of tiny, rapid oscillations at exactly 60 cycles per second. The QRS complexes are usually still visible, but they sit on top of this wide, fuzzy baseline. What it mimics: Sixty-hertz interference can obscure fine waveform details, making it difficult to see P waves or assess ST segment changes. In severe cases, the fuzzy baseline can