ECG artefacts!!! a relatively common happening

ECG artefacts!!! a relatively common happening in every day clinical life can have a wide range of presentations and can create varying clinical relevance !!!!!! 

ECG artifacts are distortions/ changes in the ECG that are not caused by the heart electrically activity by itself !!!!!  

Commonly used terms in this regard are 

1. Motion artifacts! irregular ECG baseline changes caused by movement or shaking of body. 

2. ECG artefacts! on the other hand “signals that are not related to cardiac electrical activity”

A. Artefacts due to technical problems with recording sys 

(nuisance artefact’s) 

1. malfunctioning equipment

 inc loose or fractured leads

2. accumulation of static energy

3. electromagnetic

interference(EMI). caused by power lines and electrical equipment. 

“It can be recognized as high frequency sharp signals at 60 Hz”

4. patient-related artifact such as body movement, 

5. poor electrode contact because of hairy skin or wet electrode , poor skin electrode interface creating “ pseudo double T wave “ 

B. External devices (household items/ medical equipment)

Some of the frequently used household items can include !

1. analog and digital phones, “communication devices should not be used within 1 m of the patient”

2. electric toothbrush and 

light fixtures! 

3. medical equipment 

“Electrocautery causes high-frequency and high-amplitude artifact whose recognition may be straightforward”

“Ventilation with High frequency oscillatory can also mimic some common arrhythmias like atrial flutter & VT” 

C. Implanted electronic devices

Increase use of these (mostly non cardiac) to patients for treatment of a variety of few other medical conditions. They include 

1. deep brain stimulation - Parkinson's disease/ other movement disorders, 

2. spinal cord stimulation- treatment of chronic pain, 

3. sacral nerve stimulation- overactive bladder/fecal incontinence

4. gastric electric stimulation (medically refractory Gastro paresis)

“Implanted electronic devices frequently cause gross high-frequency artifact that can hide the true ECG features” 

“These can be removed/mitigated by modifying the frequency range of the recording “

D. Artifact generated by the recording device!!!

Interestingly, few artifacts are generated by the electrocardiograph itself. 

1. On standard printed recordings, transient increase or decrease of paper speed can mimic bradycardia and tachycardia, respectively. 

2. bedside or ambulatory monitoring, tape drag can result in artifact that mimics condition like svt or VT !

“Careful analysis of the background grid can easily reveal the erroneous nature of the dysrhythmia” 

E. Artifacts related to non cardiac but physiologic events!!!

Many signals generated by bodily function have the ability to show up on the surface ECG. 

1. coughing 

“coughing spell should be suspected Whenever fuzzy/hazy artefact is followed by abrupt SN slowing and/or AV block” 

(coughing inducing Brady)

2. hiccup 

   3. shivering 

  4. Parkinsonism tremor, leading to pseudo atrial flutter ! 

   5. shaking during delirium.

Artefact’s produced by these physiologic signals that can also sometimes serve as diagnostic aids. 

“if these are analysed in the clinical context and relationship with other ECG features , can help establish certain clinical diagnoses like tremor, delirium, hypothermia, coughing induced syncope and even orthostatic tremor “

F. Some very very Unusual causes leading to artifacts can be even 

1. pulsatile flow from an AV fistula!!!! 

2. large radial artery in close proximity to the ECG recording lead !!

G. Critically wrong diagnosis as a result of artifacts!!!!

Two relevant clinical conditions frequently mimicked by artifacts May include STEMI & VT!!!! 

Such STMIs (or the Pseudo STEMIs)! can be recognized on the surface ecg by 

a. “apparent ST elevation starting with a delay after the QRS complex” 

b. Or the spiked helmet sign) !! 

((A dome-shaped elevation of the ST-segment /An upward shift of the baseline before the QRS complex and ending after QRS) 

If artefact are mostly visible in leads I and II, the most probable source of interference can be muscle contractions or movement within the patient, which may be due to patient movement or improper electrode placement.

Electrocardiographic artifact are a common every day nuisance which, if not recognized as such, can lead to erroneous diagnoses and then inappropriate interventions!!!

Careful analysis of such signals, however, usually helps find the source of the artifact which can then be eliminated !!!

Thanks