CET ECG Equipment Operation & Maintenance 3

Question 1

A 60 Hz interference pattern on an ECG tracing most commonly indicates which problem?

Accepted Answer

Poor electrode-to-skin contact or AC electrical interference

Answer

60 Hz (AC) interference appears as a rapid, regular oscillation on the baseline and is typically caused by poor electrode contact or nearby electrical devices.

Question 2

Which lead configuration uses the left arm electrode as the positive terminal and the right arm as the negative terminal?

Accepted Answer

Lead I

Answer

Lead I measures the potential difference from right arm (negative) to left arm (positive), reflecting lateral heart activity.

Question 3

What is the primary reason disposable adhesive ECG electrodes have a defined expiration date?

Accepted Answer

The conductive gel dries out, increasing impedance and reducing signal quality

Answer

Expired electrodes have dehydrated gel that increases skin-electrode impedance, producing poor signal quality and artifact.

Question 4

During a 12-lead ECG, the technician observes that aVR, aVL, and aVF all show artifact but limb leads I, II, and III are clean. What is the most likely cause?

Accepted Answer

A faulty right leg (ground) electrode connection

Answer

The augmented leads (aVR, aVL, aVF) are derived differently than the bipolar leads; a faulty ground (RL) electrode selectively corrupts them while bipolar leads may appear relatively clean.

Question 5

What thermal paper storage condition will cause premature darkening or degradation of ECG paper?

Accepted Answer

Exposure to heat, humidity, or direct sunlight

Answer

Thermal paper is heat-sensitive; exposure to heat, humidity, or UV light causes premature darkening and makes tracings unreadable.

(CET) Certified Electrocardiogram Technician Practice Test

(CET) Certified Electrocardiogram Technician Practice Test

CET ECG Equipment Operation & Maintenance 3