Unit 5: Artefact, Troubleshooting, and Special Procedures

• Topic 01

  Artefact Types — Somatic Tremor, AC Interference, Wandering Baseline, Lead Pop

  45 questions
• Topic 02

  Artefact Causes and Corrective Actions

  45 questions
• Topic 03

  Holter Monitor — Patient Instructions, Diary, and Lead Placement

  45 questions
• Topic 04

  Event Monitor and Implantable Loop Recorder Overview

  45 questions
• Topic 05

  Exercise Stress Testing — Protocol, Safety, and Technician Role

  45 questions
• Topic 06

  Documentation and Reporting ECG Results

  45 questions

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

1. Which arrhythmia is a major target for ILR surveillance in patients with cryptogenic stroke?

   • A
     Accelerated idioventricular rhythm
   • B
     First-degree atrioventricular block
   • C
     Premature ventricular contractions (PVCs)
   • D
     Paroxysmal atrial fibrillation (AF)
     Correct answer
   Explanation

   Paroxysmal atrial fibrillation is a major but often occult cause of cardioembolic stroke. It may occur briefly and intermittently, evading detection by short-duration monitoring. ILR surveillance over months to years significantly increases detection rates of paroxysmal AF in cryptogenic stroke patients, enabling anticoagulation therapy to reduce recurrent stroke risk. Key takeaway: ILR in cryptogenic stroke targets detection of paroxysmal AF to guide anticoagulation.

2. A patient forgets to fill in the diary during their 24-hour Holter monitoring. What is the clinical impact and what should the technician do at device return?

   • A
     The recording should be discarded and the patient rescheduled for repeat monitoring
   • B
     The clinical impact is limited to missing the timing of medications; all arrhythmia analysis proceeds normally
   • C
     The clinical value is significantly reduced because symptom-rhythm correlation is impossible without diary entries; the technician should ask the patient to recall and reconstruct as much diary information as possible before the device is analysed
     Correct answer
   • D
     No clinical impact; automated arrhythmia detection software replaces the need for a patient diary
   Explanation

   An incomplete diary significantly reduces the Holter study's clinical utility because arrhythmias cannot be correlated with symptoms. At device return, the technician should attempt to help the patient reconstruct the diary from memory: key events, activity timing, any symptoms felt. While imperfect, partial diary information is better than none. Key takeaway: incomplete diary significantly reduces clinical value; attempt retrospective reconstruction at device return to salvage what correlation is possible.

3. A patient with essential tremor cannot hold still, and somatic tremor artefact persists after warming, repositioning, and standard limb placement. Which alternative approach should the technician try next to reduce the artefact?

   • A
     Activate both the AC filter and the low-frequency filter simultaneously to suppress all oscillations
   • B
     Move the limb electrodes to the most bony, muscle-poor areas available (e.g., directly over the bony prominences of the wrist and ankle) and allow the patient to rest their arms and legs on the table fully supported
     Correct answer
   • C
     Ask the patient to grip the table rails tightly during the recording to reduce limb tremor amplitude
   • D
     Apply additional electrodes on the neck and upper chest to bypass the tremoring limbs entirely
   Explanation

   When standard corrective measures fail for essential tremor, the technician should optimise electrode placement on the most muscle-poor bony sites and ensure the limbs are fully supported to minimise voluntary postural muscle activity. Having the patient rest arms and legs flat on the table, fully supported, reduces the postural muscle contribution to tremor artefact. Filters should not be layered indiscriminately (risk of ST distortion), and no improvised electrode positions substitute for the approved Mason-Likar or standard limb sites. Key takeaway: full limb support combined with the most bony available electrode sites is the preferred non-filter approach when tremor persists.