Practice Test GeeksCRAT - Certified Rhythm Analysis Technician Practice Test
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ECG Waveform Measurements and Intervals Flashcards

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

Read the first 6 ECG Waveform Measurements and Intervals flashcards as text

  1. What is the normal duration of the PR interval on a standard ECG?

    Answer: 0.12–0.20 seconds

    The normal PR interval ranges from 0.12 to 0.20 seconds (3–5 small squares).

  2. On standard ECG paper, one large square represents how many seconds?

    Answer: 0.20 seconds

    One large square on standard ECG paper equals 0.20 seconds (200 ms) at the standard paper speed of 25 mm/sec.

  3. A QRS complex measuring 0.14 seconds is considered:

    Answer: Wide or abnormal

    A QRS duration greater than 0.12 seconds is considered wide and suggests a bundle branch block or ventricular origin.

  4. The QT interval is measured from:

    Answer: Start of Q wave to end of T wave

    The QT interval is measured from the beginning of the QRS complex to the end of the T wave and represents total ventricular depolarization and repolarization.

  5. Which waveform on the ECG represents ventricular repolarization?

    Answer: T wave

    The T wave represents ventricular repolarization — the recovery phase of the ventricles after contraction.

  6. A corrected QT (QTc) interval greater than 500 ms is clinically significant because it:

    Answer: Increases the risk of Torsades de Pointes

    A prolonged QTc >500 ms significantly increases the risk of Torsades de Pointes, a potentially fatal ventricular arrhythmia.

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