When only precordial electrodes are reversed, or just those of the limbs, excluding the neutral lead, the shapes of waves are inverted or do not change, and the interval duration is not modified. They also cause shifts in P waves and the QRS axis, and they may mimic ectopic atrial rhythms, fascicular block or dextrocardia the latter occurring with left arm‐right arm reversal. Incorrect connections of electrodes during ECG recordings may resemble rhythm or conduction alterations, myocardial ischemia or infarction. It has been estimated that errors in the placement of electrodes occur in 0.4% to 4% of ECGs performed (Kors & van Herpen, 2001). This is due to lack of filters for alternating current systems or a poor operation of the device. The artifacts produced by alternating current cause a “darkened reinforcement” in the ECG baseline, often making an analysis of rhythm difficult. In such cases, any device that may interfere with the ECG signal should be turned off: these include cell phones within 25 cm of the ECG sensor module, electrical beds, surgical and fluorescent lamps. The presence of other electrical devices in the room where the ECG is being conducted may cause recordings with electrical interference. However, on a more thorough inspection, P waves are visible. When the skeletal muscles experience shaking, the ECG is “bombarded” by apparently random electrical activity.Īn irregular electrocardiogram (ECG) baseline may resemble atrial fibrillation (AF) (Finsterer, Stöllberger, & Gatterer, 2003) or atrial flutter (Baranchuk & Kang, 2009 Barrett, Kelly, Halley, & Sugrue, 2007 Hwang, Chen, Sung, & Lee, 2014 Nam, Best, Greaves, & Dayananda, 2016 Prabhavathi, Ravindranath, Moorthy, & Manjunath, 2009), and a slow regular rhythm may suggest the possibility of AF with complete AV block or junctional escape rhythm. Examples of motion artifacts include tremors with no evident cause, Parkinson’s disease, cerebellar or intention tremor, anxiety, hyperthyroidism, multiple sclerosis, and drugs such as amphetamines, xanthines, lithium, benzodiazepines, or shivering (due to hypothermia, fever (rigor due to shaking), cardiopulmonary resuscitation by chest compression (oscillations of great amplitude) and patients who move their limbs during the test, causing sudden irregularities in the ECG baseline that may resemble premature contractions or interfere with ECG wave shapes, or other supraventricular and ventricular arrhythmias. Motion artifacts are due to shaking with rhythmic movement. As a result of artifacts, the components of the electrocardiogram ( ECG) such as the baseline and waves can be distorted.
Electrocardiographic artifacts are defined as electrocardiographic alterations, not related to cardiac electrical activity.
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