A nurse notices frequent artifacts on the ECG monitor for a client whose leads are connected by cable to a console at the bedside. The nurse examines the client to determine the cause. Which of the following items is unlikely to be responsible for the artifact?
A. Frequent movement of the client.
B. Tightly secured cable connections.
C. Leads applied over hairy areas.
D. Leads applied to the limbs.
Correct Answer: B. Tightly secured cable connections.
Motion artifact, or “noise,” can be caused by frequent client movement, electrode placement on limbs, and insufficient adhesion to the skin, such as placing electrodes over hairy areas of the skin. Electrode placement over bony prominences also should be avoided. Signal interference can also occur with electrode removal and cable disconnection. The artifacts produced by alternating current cause a “darkened reinforcement” in the ECG baseline, often making an analysis of rhythm difficult. This is due to lack of filters for alternating current systems or a poor operation of the device.
Option A: In Parkinson’s disease and parkinsonian syndromes, continuous muscle twitching can be mistaken for atrial flutter (pseudo?atrial flutter) due to gross and constant irregularities with a 300 bpm rate. In such cases, electrodes should be placed at the upper part of the arms and legs. To eliminate limb tremors due to Parkinson’s disease, the electrodes should be placed at the roots of the limbs, which attenuates or abolishes the tremors and the myopotentials.
Option C: Incorrect connections of electrodes during ECG recordings may resemble rhythm or conduction alterations, myocardial ischemia or infarction. 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.
Option D: A frequent mistake when performing an ECG is a positioning of the right precordial leads (V1, V2, V3); too high or too low, i.e., above the 4th intercostal space observed in 50% of tracings or inferior and left shift in 30%–50% of the cases in leads V4 through V6, which indicates that these lateral precordial leads are commonly placed outside their respective anatomical sites.
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