CET Holter Monitoring & Ambulatory ECG 3 — Questions and Answers
Question 1: A Holter monitor uses a modified Mason-Likar lead system. Compared to standard 12-lead ECG limb leads, the limb electrodes are repositioned to:
- The distal extremities to improve signal
- The torso to reduce motion artifact (Correct answer)
- The neck and shoulders for better P-wave detection
- The standard 12-lead positions
Correct answer: The torso to reduce motion artifact
In the Mason-Likar system, limb electrodes are moved to the torso to minimize movement artifact during ambulatory monitoring.
Question 2: Which Holter finding is considered a class I indication for permanent pacemaker implantation?
- Sinus bradycardia of 52 bpm during sleep
- Asymptomatic type I second-degree AV block
- Symptomatic sinus pauses greater than 3 seconds while awake (Correct answer)
- Frequent PACs with no associated symptoms
Correct answer: Symptomatic sinus pauses greater than 3 seconds while awake
Symptomatic sinus node dysfunction with documented pauses causing symptoms meets class I criteria for permanent pacing per ACC/AHA guidelines.
Question 3: During ambulatory ECG monitoring, ST-segment depression that occurs without symptoms is termed:
- Pseudo-ST depression
- Silent myocardial ischemia (Correct answer)
- Benign repolarization change
- Vasospastic angina
Correct answer: Silent myocardial ischemia
Asymptomatic ST depression meeting ischemic criteria (≥1 mm, horizontal/downsloping, ≥1 min duration) is classified as silent myocardial ischemia.
Question 4: A patient wears a continuous-loop event monitor for 30 days. This device differs from a standard Holter monitor primarily because it:
- Records continuously for 30 days without a loop
- Only saves data when the patient activates it after feeling symptoms
- Continuously records but only retains data around patient-triggered events (Correct answer)
- Transmits data wirelessly to the physician in real time
Correct answer: Continuously records but only retains data around patient-triggered events
A continuous-loop event monitor constantly records but overwrites old data, retaining only the minutes before and after the patient presses the event button.
Question 5: A Holter report shows frequent couplets (pairs of PVCs). What is the minimum number of consecutive PVCs that defines ventricular tachycardia?
- 2
- 3 (Correct answer)
- 5
- 6
Correct answer: 3
By definition, three or more consecutive PVCs at a rate ≥100 bpm constitutes ventricular tachycardia.
Question 6: Which of the following best describes the '1x1x1 rule' used to identify significant ST changes on Holter monitoring?
- 1 mm depression, 1 minute duration, 1 hour apart from prior episode
- 1 mm depression or elevation, lasting at least 1 minute, in at least 1 lead (Correct answer)
- 1 mm change, in 1 lead, occurring at least 1 time per hour
- 1 mm change, 1 lead, within 1 minute of symptom onset
Correct answer: 1 mm depression or elevation, lasting at least 1 minute, in at least 1 lead
The 1x1x1 rule defines significant ST change as ≥1 mm deviation lasting ≥1 minute in at least 1 lead, used to flag potential ischemia on Holter.
Question 7: When scanning Holter recordings using software, the technician's primary role is to:
- Accept all computer-generated beat classifications without review
- Verify, edit, and confirm computer auto-analysis for accuracy (Correct answer)
- Manually measure each QRS interval without software assistance
- Generate the final report without physician review
Correct answer: Verify, edit, and confirm computer auto-analysis for accuracy
Holter technicians must critically review and correct automated beat classifications because software algorithms are imperfect and can misclassify artifact or arrhythmias.
CET Holter Monitoring & Ambulatory ECG 3
A Holter monitor uses a modified Mason-Likar lead system.
Compared to standard 12-lead ECG limb leads, the limb electrodes are repositioned to: