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CET — Certified EKG Technician (NHA)

Prepare for CET — Certified EKG Technician (NHA) with practice questions covering 37 topics. Build your knowledge, track your progress, and study effectively with AH Prep.

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What’s in it.

5 units

Sample questions

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A few questions from this module, with the answer and a full explanation. The complete bank is available when you start practising.

  1. What is the anatomical origin of ventricular arrhythmias?

    • Above the bundle of His, in the atria or AV junction
    • Below the bundle of His, within the ventricular myocardium or Purkinje fibres
      Correct answer
    • In the AV node and bundle of His only
    • In the pulmonary veins only
    Explanation

    Ventricular arrhythmias originate below the bundle of His, in the ventricular myocardium or Purkinje fibres. Because they do not use the normal His-Purkinje system for rapid conduction, the QRS complex is wide (≥0.12 s) and bizarrely shaped. This distinguishes them from supraventricular arrhythmias, which originate above the bundle of His. Key takeaway: ventricular arrhythmias originate below the bundle of His — wide, abnormal QRS is the result.

  2. What happens at the end of a prolonged sinus pause to prevent asystole?

    • Atrial flutter emerges to maintain cardiac output
    • Ventricular fibrillation is triggered to maintain perfusion pressure
    • The AV node blocks all further conduction until the SA node recovers
    • A subsidiary pacemaker (junctional or ventricular) generates an escape beat
      Correct answer
    Explanation

    When the SA node fails to fire and the pause becomes prolonged, the heart's backup (subsidiary) pacemakers activate. The AV junction (rate 40–60 bpm) usually fires first, producing a narrow QRS escape beat. If the junction also fails, ventricular pacemakers (rate 20–40 bpm) provide a wider, slower escape beat. These escape beats are protective mechanisms that prevent asystole. Key takeaway: prolonged sinus pause → junctional or ventricular escape beat terminates the pause.

  3. What artefact results from the patient's arms being tensed rather than relaxed during ECG recording?

    • Motion artefact — irregular large deflections caused by the patient shifting position on the bed
    • Baseline wander — a slow, undulating shift of the isoelectric line
    • 60-Hz interference — a fine, regular oscillation superimposed on the ECG tracing
    • Electromyographic (EMG) artefact — a high-frequency muscle noise that thickens and blurs the baseline
      Correct answer
    Explanation

    Skeletal muscle activity generates electrical signals in the frequency range of 100–1,000 Hz. These signals are picked up by ECG electrodes whenever nearby muscles are contracted, including arm and shoulder muscles when the patient tenses. The resulting EMG artefact appears as a high-frequency, irregular thickening of the ECG baseline and all waveforms, making P waves and ST segments difficult to see. Instructing the patient to relax their arms and remain still eliminates this source of noise. Key takeaway: Tensed arm muscles generate EMG artefact that appears as high-frequency baseline noise — instruct patients to relax their arms completely before recording.