CMT Monitoring Techniques and Equipment 3 — Questions and Answers
Question 1: Which monitoring lead is considered best for detecting ST-segment changes during ischemia monitoring?
- Lead I
- Lead II
- Lead V5 (or MCL5) (Correct answer)
- Lead aVR
Correct answer: Lead V5 (or MCL5)
Lead V5 (or MCL5) is most sensitive for detecting lateral wall ischemia and ST-segment changes, making it preferred for ischemia monitoring.
Question 2: What is the correct skin preparation technique before applying monitoring electrodes to maximize signal quality?
- Apply electrode directly to intact skin without preparation
- Clean skin with alcohol, allow to dry, and lightly abrade if needed (Correct answer)
- Shave the area and immediately apply the electrode
- Apply electrode gel directly to unwashed skin
Correct answer: Clean skin with alcohol, allow to dry, and lightly abrade if needed
Skin should be cleaned with alcohol, allowed to dry completely, and lightly abraded to remove dead skin cells and reduce impedance.
Question 3: A telemetry transmitter battery is low. What is the most likely effect on monitoring quality?
- Increased heart rate readings
- Signal dropout, artifact, or loss of transmission (Correct answer)
- Inverted QRS complexes
- Prolonged QT interval on the monitor
Correct answer: Signal dropout, artifact, or loss of transmission
Low battery in a telemetry transmitter causes signal weakness, resulting in signal dropout, artifact, or complete loss of transmission to the monitoring station.
Question 4: Which factor most directly affects the radiofrequency signal range of a telemetry system?
- Patient heart rate
- Building construction materials and competing wireless signals (Correct answer)
- Number of electrodes used
- Monitor paper speed
Correct answer: Building construction materials and competing wireless signals
Building materials (concrete, steel) and competing wireless devices (Wi-Fi, other telemetry) are primary factors limiting telemetry transmission range.
Question 5: What is the function of the RA electrode in a standard 3-lead monitoring setup?
- It serves as the positive electrode for Lead II
- It serves as the negative electrode and reference for Lead II (Correct answer)
- It serves as the ground electrode
- It detects right ventricular activity only
Correct answer: It serves as the negative electrode and reference for Lead II
In Lead II, the RA electrode serves as the negative pole, while the LL electrode is positive, with the LA electrode serving as ground.
Question 6: When using a 5-lead monitoring system compared to a 3-lead system, what additional capability is provided?
- Ability to measure blood pressure simultaneously
- Simultaneous monitoring of a precordial chest lead (e.g., V1) (Correct answer)
- Automatic defibrillation capability
- More accurate heart rate calculation
Correct answer: Simultaneous monitoring of a precordial chest lead (e.g., V1)
A 5-lead system adds a chest (precordial) electrode, allowing simultaneous display of limb leads and one chest lead for enhanced diagnostic capability.
Question 7: A patient's telemetry shows intermittent artifact that occurs every time the patient raises their left arm. What is the most likely cause?
- Atrial flutter
- Lead wire or electrode on the left arm or shoulder becoming intermittently loose (Correct answer)
- Ventricular bigeminy
- Pacemaker spike artifact
Correct answer: Lead wire or electrode on the left arm or shoulder becoming intermittently loose
Motion-related artifact that correlates with arm movement indicates a loose electrode or lead wire at the left arm/shoulder attachment site.
CMT Monitoring Techniques and Equipment 3
Which monitoring lead is considered best for detecting ST-segment changes during ischemia monitoring?