ECG Troubleshooting and Artifacts Flashcards

Sixty-cycle (60 Hz) interference on an ECG most likely results from which cause?

Answer: Nearby electrical equipment or poor electrode grounding

60 Hz artifact appears as a thick, fuzzy baseline caused by electromagnetic interference from AC power sources including nearby electrical equipment or inadequate grounding.

Baseline wander on an ECG is most commonly caused by which factor?

Answer: Patient breathing or movement causing electrode-skin interface changes

Baseline wander results from slow undulation of the baseline caused by patient movement, respiration, poor electrode contact, or electrode gel drying.

A patient's ECG shows a completely flat line in lead II only, while other leads record normally. The most likely cause is which of the following?

Answer: Disconnected or failed lead II electrode

A flat line in one lead only, while other leads continue to show cardiac activity, indicates a technical failure specific to that lead — most likely a disconnected electrode.

Which action is most appropriate when a patient's ECG shows muscle tremor artifact that obscures rhythm interpretation?

Answer: Reposition the electrodes away from muscle-heavy areas and ask the patient to relax

Muscle tremor creates irregular high-frequency artifact that can mimic arrhythmias. Repositioning electrodes to bony prominences and asking the patient to relax reduces this artifact.

If limb leads show reversed arm electrode placement (right and left arm switched), which lead will appear inverted compared to a correct recording?

Answer: Lead I

Lead I measures the potential difference between the left arm (positive) and right arm (negative). Switching these electrodes inverts lead I and swaps leads II and III.

Which ECG parameter should be verified first when the paper tracing appears abnormally large or small for all waveforms?

Answer: Calibration/gain setting (should show 10 mm/mV deflection)

Standard ECG calibration is 10 mm per millivolt. If all waveforms are too large or too small, the gain (calibration) setting has been changed from the standard.