Questions, Answers & Rationales (Latest
2026/2027)
Ace your Relias Dysrhythmia Basic A Exam with this ultimate study resource. Includes 50
realistic practice questions with correct answers highlighted and comprehensive
Rationales directly following every item. Master core ECG measurements, atrial/junctional
rhythms, heart blocks (Mobitz I, II, and 3rd degree), lethal ventricular arrhythmias, and
pacemaker malfunctions. Perfect for telemetry nurses and progressive care staff looking to
pass their competency assessment on the first try.
, 1. What is the standard duration of one small box on an ECG grid?
A. 0.01 seconds
B. 0.04 seconds
C. 0.12 seconds
D. 0.20 seconds
Rationale: On standard EKG graph paper, a single small box measures 1 mm by 1 mm
and represents 0.04 seconds horizontally.
2. What is the standard duration of one large box on an ECG grid?
A. 0.04 seconds
B. 0.12 seconds
C. 0.20 seconds
D. 0.40 seconds
Rationale: A large box consists of 5 small boxes horizontally. Multiplying 5 by 0.04
seconds yields 0.20 seconds.
3. A normal PR interval measures between which of the following time frames?
A. 0.04 to 0.10 seconds
B. 0.12 to 0.20 seconds
C. 0.20 to 0.35 seconds
D. 0.35 to 0.44 seconds
Rationale: A normal PR interval is between 3 and 5 small boxes wide, which translates
to 0.12 to 0.20 seconds. Anything longer indicates a conduction delay.
4. Which measurement represents a normal, non-widened QRS complex duration?
A. Less than 0.12 seconds
B. 0.12 to 0.20 seconds
C. 0.20 to 0.30 seconds
D. Greater than 0.30 seconds
Rationale: A normal ventricular conduction pathway yields a narrow QRS complex
measuring under 3 small boxes, or less than 0.12 seconds.
5. A patient’s telemetry strip demonstrates a regular rhythm, a heart rate of 72 bpm,
upright uniform P waves before every QRS, a PR interval of 0.16 seconds, and a QRS of
0.08 seconds. What is this rhythm?
A. Sinus Bradycardia
B. Normal Sinus Rhythm
C. Sinus Tachycardia