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Electrocardiogram Knowledge Answers and Questions Flashcards

7 cards from real ECG practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Electrocardiogram Knowledge Answers and Questions flashcards as text

  1. 60-cycle (AC) interference on an ECG usually appears as:

    Answer: Uniform, thick, regular fine spikes across the tracing

    AC interference produces a consistent 60 Hz fuzzy pattern from nearby electrical sources.

  2. The SA node, the heart's natural pacemaker, is located in which chamber?

    Answer: Right atrium

    The sinoatrial node sits in the upper wall of the right atrium.

  3. Which precordial lead is placed at the 5th intercostal space, midclavicular line?

    Answer: V4

    V4 is located at the 5th intercostal space along the midclavicular line.

  4. A wandering baseline artifact is most commonly caused by:

    Answer: Poor electrode contact or patient movement/respiration

    Loose electrodes, lotion on skin, or breathing cause the baseline to drift.

  5. The PR interval measures the time from:

    Answer: Start of the P wave to the start of the QRS complex

    The PR interval reflects conduction from the atria through the AV node to the ventricles.

  6. Which limb lead views the heart from the left arm to the left leg?

    Answer: Lead III

    Lead III records the potential between the left arm and left leg.

  7. Before applying electrodes, the ECG technician should prepare the skin by:

    Answer: Cleaning and, if needed, lightly abrading and shaving the site

    Clean, dry, hair-free skin ensures good electrode contact and a clear signal.

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Sources & references

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  1. nhanow.com — Passing score, test delivery, eligibility, renewal, score release, time limit · verified Oct 2026
  2. cci-online.org — Test delivery, fees, exam format, passing score, renewal, score release · verified Oct 2026