CVT Holter & Ambulatory Monitoring 3 — Questions and Answers
Question 1: A patient is prescribed a 30-day event monitor. Which type of monitor would BEST capture infrequent arrhythmias that the patient cannot predict?
- Auto-triggered loop recorder with patient-activated backup (Correct answer)
- Standard patient-activated event recorder
- Continuous 30-day Holter recorder
- Implantable loop recorder
Correct answer: Auto-triggered loop recorder with patient-activated backup
An auto-triggered loop recorder continuously records and saves strips automatically when arrhythmia detection criteria are met, capturing events the patient may not feel.
Question 2: During Holter scanning, you notice that the QRS morphology alternates between two different configurations every other beat. This pattern is BEST described as:
- Ventricular bigeminy with alternating morphology (Correct answer)
- Sinus rhythm with first-degree AV block
- Ventricular tachycardia
- Accelerated idioventricular rhythm
Correct answer: Ventricular bigeminy with alternating morphology
Alternating QRS morphology every other beat with a regular pattern is consistent with bigeminy where PVCs have a consistent ectopic focus morphology alternating with normal beats.
Question 3: What is the recommended minimum sampling rate for digital Holter recorders to accurately reproduce high-frequency QRS components?
- 128-200 Hz per channel (Correct answer)
- 40-60 Hz per channel
- 500-1000 Hz per channel
- 25-50 Hz per channel
Correct answer: 128-200 Hz per channel
A sampling rate of 128-200 Hz is the standard minimum for ambulatory monitoring to accurately capture QRS morphology without missing high-frequency components.
Question 4: A Holter report documents 'R-on-T phenomenon.' Why is this significant?
- It can trigger ventricular fibrillation by occurring during the vulnerable period of repolarization (Correct answer)
- It indicates complete heart block requiring pacemaker implantation
- It represents normal aberrant conduction during tachycardia
- It is a benign finding seen in athletes with high vagal tone
Correct answer: It can trigger ventricular fibrillation by occurring during the vulnerable period of repolarization
R-on-T occurs when a PVC lands on the T wave during the vulnerable repolarization period, potentially initiating ventricular fibrillation.
Question 5: A patient undergoes a Holter test to evaluate medication efficacy for atrial fibrillation. Which Holter parameter is MOST useful for this assessment?
- Ventricular rate during AF episodes and percentage of time in AF (Correct answer)
- Maximum heart rate achieved during the study
- Number of PACs triggering AF episodes
- PR interval duration during sinus rhythm
Correct answer: Ventricular rate during AF episodes and percentage of time in AF
Ventricular rate control and AF burden (percentage of time in AF) are the primary metrics for evaluating rate-control and rhythm-control medication efficacy.
Question 6: Which artifact on a Holter recording can mimic ventricular fibrillation and is important to distinguish from the real arrhythmia?
- Motion artifact from a loose electrode during vigorous exercise (Correct answer)
- Baseline wander from respiratory movement
- 60 Hz electrical interference from household appliances
- Lead reversal artifact
Correct answer: Motion artifact from a loose electrode during vigorous exercise
Vigorous motion artifact from a loose electrode creates a chaotic, high-amplitude signal that can be mistaken for ventricular fibrillation on automated analysis.
Question 7: What is the primary advantage of a 48-hour Holter recording compared to a standard 24-hour recording?
- Increased probability of capturing infrequent arrhythmias and symptoms (Correct answer)
- Improved signal quality due to longer averaging time
- Better patient compliance with shorter wear time
- More accurate ST-segment analysis
Correct answer: Increased probability of capturing infrequent arrhythmias and symptoms
Extending the recording to 48 hours nearly doubles the chance of capturing arrhythmias or correlating symptoms that occur less than once daily.
CVT Holter & Ambulatory Monitoring 3
A patient is prescribed a 30-day event monitor.
Which type of monitor would BEST capture infrequent arrhythmias that the patient cannot predict?