Relias Dysrhythmia Basic Test Comprehensive 300 Question Exam Bank And Answers With Rationales Latest This Year

RELIAS DYSRHYTHMIA BASIC TEST
COMPREHENSIVE 300 QUESTION
EXAM BANK AND ANSWERS WITH
RATIONALES LATEST THIS YEAR


SECTION 1: CARDIAC ANATOMY & ELECTROPHYSIOLOGY (Questions
130)


Question 1
What is the normal intrinsic firing rate of the Sinoatrial (SA) node?
A) 4060 beats per minute
B) 60100 beats per minute
C) 100150 beats per minute
D) 2040 beats per minute


Correct Answer: B) 60100 beats per minute


Rationale: The SA node, the heart's primary pacemaker, normally fires at 60100
beats per minute. Option A (4060) is the intrinsic rate of the AV node/junctional
tissue. Option C (100150) is too fast for the SA node and is more consistent with
sinus tachycardia or an ectopic atrial focus. Option D (2040) is the intrinsic rate of
the Purkinje fibers/ventricular pacemaker.

,Question 2
Which structure is known as the heart's primary pacemaker?
A) Atrioventricular (AV) node
B) Bundle of His
C) Sinoatrial (SA) node
D) Purkinje fibers


Correct Answer: C) Sinoatrial (SA) node


Rationale: The SA node is the primary pacemaker because it has the fastest
intrinsic firing rate (60100 bpm) and overrides all other pacemaker sites. The AV
node (A) is the secondary pacemaker (4060 bpm). The Bundle of His (B) and
Purkinje fibers (D) are lower in the conduction system and serve as tertiary
pacemakers (2040 bpm).




Question 3
What does the P wave represent on an ECG tracing?
A) Ventricular depolarization
B) Ventricular repolarization
C) Atrial depolarization
D) Atrial repolarization


Correct Answer: C) Atrial depolarization

,Rationale: The P wave represents atrial depolarization, which is the electrical
activation of the atria leading to atrial contraction. Ventricular depolarization (A) is
represented by the QRS complex. Ventricular repolarization (B) is represented by
the T wave. Atrial repolarization (D) is not visible on a standard ECG as it is
masked by the QRS complex.




Question 4
The PR interval represents the time it takes for the electrical impulse to travel from
the:
A) SA node to the AV node
B) AV node to the Purkinje fibers
C) Atria to the ventricles (through the AV node)
D) Bundle of His to the ventricular muscle


Correct Answer: C) Atria to the ventricles (through the AV node)


Rationale: The PR interval measures the time from the onset of atrial
depolarization (P wave) to the onset of ventricular depolarization (QRS),
representing conduction through the atria, AV node, and bundle of His. Option A
is incomplete as it doesn't include ventricular activation. Options B and D represent
only portions of ventricular conduction.




Question 5
What is the normal duration of the PR interval in an adult?

, A) 0.04 0.10 seconds
B) 0.12 0.20 seconds
C) 0.20 0.30 seconds
D) 0.08 0.12 seconds


Correct Answer: B) 0.12 0.20 seconds


Rationale: The normal PR interval is 0.120.20 seconds (35 small boxes on ECG
paper). Option A (0.040.10) is too short and suggests preexcitation or junctional
rhythm. Option C (0.200.30) indicates first degree AV block. Option D (0.080.12)
is the normal QRS duration.




Question 6
The QRS complex on an ECG represents:
A) Atrial depolarization
B) Ventricular depolarization
C) Atrial repolarization
D) Ventricular repolarization


Correct Answer: B) Ventricular depolarization


Rationale: The QRS complex represents ventricular depolarization, the electrical
activation of the ventricles. Atrial depolarization (A) is the P wave. Atrial
repolarization (C) is not visible on ECG. Ventricular repolarization (D) is the T
wave.