NHA Certified Clinical Medical Assistant (CCMA)Clinical Patient CareHard
A medical assistant is performing an electrocardiogram (ECG) on a patient. The MA notices electrical interference on the tracing, characterized by a series of small, rapid, irregular spikes. Which of the following artifacts does this describe?
- ASomatic tremor
- BAlternating current (AC) interference
- CInterrupted baseline
- DWandering baseline
Show answer & explanationAnswer & explanation
Correct answer: B. Alternating current (AC) interference
Alternating current (AC) interference is caused by electrical equipment in the vicinity of the patient or faulty wiring, appearing as a series of uniform, small, rapid, irregular spikes (or jagged waves) on the ECG tracing.
Why the other options are wrong
- A. Somatic tremor (muscle artifact) appears as erratic, jagged peaks of varying amplitude and frequency, often due to patient movement or shivering.
- C. Interrupted baseline is a break in the tracing, indicating a disconnected lead or cable.
- D. Wandering baseline is when the baseline drifts up and down, often due to loose electrodes or patient breathing.
ECG Artifacts
Unwanted electrical activity or interference that appears on an ECG tracing, obscuring the true cardiac electrical signals.
- AC interference: electrical interference, uniform spikes.
- Somatic tremor: muscle movement, erratic spikes.
- Wandering baseline: loose electrodes, baseline drift.
- Interrupted baseline: disconnected lead, flat line break.
Memory trick: AC: A Constant Current of tiny spikes!