CET EKG Technician Skills and Knowledge Base 3 — Questions and Answers
Question 1: What does ST segment elevation in two or more contiguous leads typically indicate?
- Ventricular hypertrophy
- Acute myocardial infarction or injury (Correct answer)
- Bundle branch block
- Electrolyte imbalance
Correct answer: Acute myocardial infarction or injury
ST elevation in contiguous leads is the hallmark of acute myocardial injury (STEMI) and requires immediate clinical attention.
Question 2: When recording a 12-lead EKG, the standard paper speed in the United States is:
- 10 mm/sec
- 25 mm/sec (Correct answer)
- 50 mm/sec
- 100 mm/sec
Correct answer: 25 mm/sec
Standard EKG paper speed in the US is 25 mm/sec, meaning each small box horizontally equals 0.04 seconds.
Question 3: A patient's EKG shows a sawtooth baseline at 300 bpm with a ventricular rate of 150 bpm. This rhythm is:
- Atrial fibrillation
- Atrial flutter with 2:1 block (Correct answer)
- Multifocal atrial tachycardia
- Supraventricular tachycardia
Correct answer: Atrial flutter with 2:1 block
Atrial flutter typically shows a sawtooth pattern at ~300 bpm; with 2:1 conduction, the ventricular rate is ~150 bpm.
Question 4: Which artifact on an EKG tracing is most commonly caused by patient movement or muscle tremor?
- AC interference (60 Hz noise)
- Baseline wander
- Somatic tremor artifact (Correct answer)
- Electrode pop artifact
Correct answer: Somatic tremor artifact
Somatic tremor artifact, from voluntary or involuntary muscle activity, produces an irregular, fuzzy baseline distortion.
Question 5: On a standard EKG, the amplitude (voltage) calibration is set so that 1 mV equals:
- 5 mm
- 10 mm (Correct answer)
- 15 mm
- 20 mm
Correct answer: 10 mm
Standard EKG calibration is 1 mV = 10 mm (two large boxes) vertically.
Question 6: Which of the following conditions can cause a prolonged QT interval?
- Hyperkalemia
- Hypercalcemia
- Hypokalemia (Correct answer)
- Hypernatremia
Correct answer: Hypokalemia
Hypokalemia (low potassium) prolongs ventricular repolarization, extending the QT interval and increasing arrhythmia risk.
Question 7: The right leg electrode in a standard 12-lead EKG serves as:
- The positive terminal for lead II
- An electrical ground to reduce noise (Correct answer)
- The negative terminal for lead aVR
- A reference for precordial leads
Correct answer: An electrical ground to reduce noise
The right leg (RL) electrode acts as an electrical ground, helping to reduce baseline noise and common-mode interference.
CET EKG Technician Skills and Knowledge Base 3
What does ST segment elevation in two or more contiguous leads typically indicate?