ECG Artifact Troubleshooting Flashcards

Which of the following artifacts can cause a false-positive diagnosis of ST-segment elevation if not recognized?

Answer: Electrode polarization causing DC offset

Electrode polarization creates a DC voltage offset that shifts the isoelectric line and can mimic ST elevation, leading to a false-positive ischemia finding.

An ECG tech is recording a patient on a hospital bed with an electric motor (e.g., alternating-pressure mattress). The ECG shows rhythmic low-frequency artifact. The BEST solution is:

Answer: Turn off the mattress motor during the ECG

The motor creates electromagnetic interference that synchronizes with its cycle; briefly switching it off eliminates the source without compromising signal integrity.

What does a 'wandering baseline' on an ECG most commonly indicate about electrode impedance?

Answer: Impedance mismatch between electrode pairs allows low-frequency noise to enter the signal

Impedance mismatch between differential input electrodes allows common-mode low-frequency signals (such as respiration) to appear as baseline wander.

A technician sees intermittent bursts of high-frequency noise corresponding to each QRS complex on a Holter monitor recording. The most likely cause is:

Answer: Saturation of the amplifier during high-amplitude QRS peaks

High-amplitude QRS signals can transiently saturate the amplifier input, producing clipping artifact that appears as high-frequency noise at each QRS.

Which characteristic of 60 Hz AC interference helps differentiate it from atrial fibrillation on a rhythm strip?

Answer: AC interference has a perfectly regular frequency of 60 cycles per second

AC interference produces a precisely regular 60-per-second oscillation, while atrial fibrillation produces irregularly irregular, variable-amplitude fibrillatory waves.

When a patient has a permanent pacemaker, a pacemaker spike artifact appears on the ECG. Which action would be INCORRECT when troubleshooting apparent artifact around these spikes?

Answer: Disable pacemaker detection mode on the ECG machine to clean up the tracing

Pacemaker detection mode must remain enabled; disabling it suppresses true pacemaker spikes, which are clinically essential for assessing pacemaker function.

A patient receiving an IV through an infusion pump with a built-in EKG monitor shows artifact. Applying a fresh set of electrodes on the contralateral limbs does not resolve the problem. The next best step is:

Answer: Ensure the infusion pump is properly grounded and check the power outlet's ground connection

A poorly grounded pump can inject leakage current into the patient circuit; verifying ground integrity removes the source of electrical interference.