Electrocardiographic artifacts in clinical practice: A logical approach to recognition and prevention

Table 1 Signal pathway and artifact risks

Step	Function	Common artifact sources	Clinical example
Generation	The heart produces approximately 1 mV currents	Competing signals from the muscle	Myopotential artifacts mimicking atrial fibrillation
Detection	Electrodes capture surface signals	Sweat, hair, poor adhesion, movement	Wandering baseline or false ST elevation (baseline drift)
Transmission	Leads carry signals	Cable fracture, patient motion, EMI	Flatline due to broken lead; saw-tooth interference from cautery
Amplification and filtering	Boosts and cleans signals	Amplifies both signal and noise; filter distortion	QRS smoothed, or ST segments flattened, spurious ST shifts
Display and printing	Trace presented	All upstream noise is now visible	Artifact interpreted as ventricular tachycardia, acceleration or deceleration artifacts

EMI: Electromagnetic interference.

Table 2 Classification of electrocardiographic artifacts with examples

Category	Source	ECG appearance	Clinical mimic	Solution
Patient-related	Tremor, shivering, respiration, movement	Irregular baseline, wandering drift	AF, flutter, VT, ST changes	Patient cooperation
Equipment-related	Loose electrodes, fractured cables, faulty machine	Baseline jumps, flatline, spikes	Asystole, VF	Change cables, better skin preparation, electrode contact
Environmental	Power-line hum, cautery, ventilators	Saw-tooth oscillations, rhythmic noise	Flutter, VT	Avoidance of equipment, notch filters
Device-related	Pacemaker, LVAD, neurostimulators, IVL	Sharp spikes, continuous noise	VF, tachycardia	Not always possible

ECG: Electrocardiogram; AF: Atrial fibrillation; VT: Ventricular tachycardia; VF: Ventricular fibrillation; LVAD: Left ventricular assist device; IVL: Intravascular lithotripsy.

Table 3 Common clinical mimics of electrocardiographic artifacts

Artifact source	ECG appearance	Clinical mimic	Recognition clues
Tremor (Parkinson’s, shivering)	Irregular baseline, absent P waves	Atrial fibrillation	P waves marching through; stable pulse
Electrocautery, ventilators	Saw-tooth baseline	Atrial flutter	Localized, no AV conduction ratio
Movement, loose cables	Wide irregular complexes	Ventricular tachycardia	Too fast; QRS visible through noise; stable patient
Loose electrode, EMI	Chaotic baseline	Ventricular fibrillation	Conscious patient; stable SpO2
Respiration, poor skin contact	Wandering baseline, pseudo ST shift	Myocardial infarction	Inconsistent, resolves with repeat
Holter/wearable motion	Drop-outs, spikes	AV block, tachycardia	Correlate with activity; not reproducible

ECG: Electrocardiogram; EMI: Electromagnetic interference; AV: Atrioventricular.