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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. Which lead is considered the ground (reference) electrode in a standard 12-lead ECG?

    Answer: Right leg (RL)

    The right leg electrode serves as the ground and does not contribute to any waveform.

  2. At standard calibration, one small (1 mm) box on the horizontal axis represents how much time?

    Answer: 0.04 seconds

    Each small box equals 0.04 seconds when paper runs at 25 mm/sec.

  3. The P wave on an ECG represents which electrical event?

    Answer: Atrial depolarization

    The P wave reflects depolarization spreading across the atria.

  4. Where should the V1 chest electrode be placed?

    Answer: 4th intercostal space, right sternal border

    V1 is positioned in the 4th intercostal space just right of the sternum.

  5. A standard ECG is normally calibrated so that 10 mm of vertical deflection equals what voltage?

    Answer: 1 millivolt

    Standard calibration sets 10 mm vertical equal to 1 mV.

  6. Which artifact is most likely caused by patient muscle tremor or shivering?

    Answer: Somatic (muscle) tremor artifact

    Muscle movement produces irregular, jagged somatic tremor artifact.

  7. The normal duration of a QRS complex in an adult is approximately:

    Answer: 0.06 to 0.10 seconds

    A normal QRS complex lasts less than 0.12 seconds, typically 0.06 to 0.10.

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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