1
IBHRE CCDS Certification Exam Actual Exam
2026/2027 | Certified Cardiac Device Specialist
Complete Practice Test with Verified Answers |
Already Graded A+ (BRAND NEW!!)
SECTION 1: BASIC CARDIAC PHYSIOLOGY & ANATOMY (15 Questions)
Q1: During phase 0 of the cardiac action potential in ventricular myocytes, which ion movement
is primarily responsible for depolarization?
A. Potassium efflux
B. Sodium influx
C. Calcium influx
D. Chloride influx
Correct Answer: B. [CORRECT]
Rationale: Phase 0 (rapid depolarization) in ventricular myocytes is caused by fast sodium
channels opening, allowing rapid sodium influx down the electrochemical gradient. This
generates the upstroke of the action potential. Calcium influx is responsible for phase 2 (plateau),
not phase 0.
Q2: The sinoatrial (SA) node is located at which anatomical site?
A. Junction of the superior vena cava and right atrial appendage
B. Coronary sinus ostium
C. Interventricular septum
D. Left atrial roof near the pulmonary veins
Correct Answer: A. [CORRECT]
Rationale: The SA node is located at the junction of the superior vena cava and the right atrial
appendage in the crista terminalis region. This position allows it to serve as the primary
pacemaker, receiving autonomic innervation and maintaining the highest intrinsic automaticity
(60-100 bpm) under normal conditions.
,2
Q3: Which ECG finding is characteristic of complete (third-degree) AV block?
A. Prolonged PR interval with dropped beats
B. AV dissociation with independent atrial and ventricular rates
C. Narrow QRS complex with 1:1 AV conduction
D. Gradual PR prolongation until a beat is dropped
Correct Answer: B. [CORRECT]
Rationale: Third-degree AV block is defined by complete failure of atrial impulses to conduct to
the ventricles, resulting in AV dissociation. The atria and ventricles beat independently at their
own rates (atrial rate typically 60-100 bpm, ventricular escape rate 20-40 bpm for junctional or
20-40 bpm for ventricular escape), with no consistent relationship between P waves and QRS
complexes.
Q4: In the His-Purkinje system, which structure represents the only normal electrical connection
between atria and ventricles?
A. Bundle of Kent
B. Accessory pathway
C. Bundle of His
D. Mahaim fibers
Correct Answer: C. [CORRECT]
Rationale: The Bundle of His is the proximal portion of the His-Purkinje system and represents
the only normal electrical pathway connecting the atrial conduction system to the ventricular
myocardium. It emerges from the AV node, penetrates the central fibrous body, and bifurcates
into the right and left bundle branches. Accessory pathways (Kent bundles, Mahaim fibers) are
abnormal connections.
Q5: During phase 4 of the pacemaker action potential, which ionic current is responsible for
spontaneous diastolic depolarization?
A. IKr (rapid delayed rectifier potassium current)
B. If (funny current) - mixed Na+/K+ influx
C. ICa,L (L-type calcium current)
D. Ito (transient outward potassium current)
Correct Answer: B. [CORRECT]
,3
Rationale: Phase 4 spontaneous depolarization in SA nodal cells is mediated primarily by the
"funny current" (If), a mixed sodium-potassium inward current activated by hyperpolarization.
This current slowly depolarizes the membrane potential toward threshold, creating automaticity.
The If current is modulated by autonomic tone (sympathetic stimulation increases If,
parasympathetic decreases it).
Q6: Which hemodynamic consequence is most likely when transitioning from atrial fibrillation
to normal sinus rhythm in a patient with a dual-chamber pacemaker programmed to VVI mode?
A. Improved cardiac output due to rate regularization
B. Loss of atrial contribution to ventricular filling (atrial kick)
C. Decreased systemic vascular resistance
D. Reduced mitral regurgitation
Correct Answer: B. [CORRECT]
Rationale: In VVI mode, the pacemaker paces and senses only in the ventricle with no atrial
tracking. Even when sinus rhythm is restored, the ventricle is paced asynchronously to atrial
activity, resulting in loss of AV synchrony and the atrial contribution to ventricular filling (atrial
kick), which comprises 15-25% of cardiac output, particularly important in patients with reduced
ventricular compliance.
Q7: The normal intrinsic rate of the AV node under conditions of complete SA node failure is
approximately:
A. 20-40 beats per minute
B. 40-60 beats per minute
C. 60-80 beats per minute
D. 80-100 beats per minute
Correct Answer: B. [CORRECT]
Rationale: The AV node exhibits secondary pacemaker activity with an intrinsic escape rate of
40-60 beats per minute. This is slower than the SA node (60-100 bpm) but faster than ventricular
escape rhythms (20-40 bpm). The hierarchical nature of cardiac pacemakers ensures that if the
primary pacemaker fails, a subsidiary pacemaker can maintain cardiac output, albeit at a slower
rate.
SATA Question - Cardiac Conduction System:
Q8: Which structures are part of the normal cardiac conduction system? Select all that apply.
A. Sinoatrial (SA) node
, 4
B. Atrioventricular (AV) node
C. Bundle of His
D. Purkinje fibers
E. Bachmann's bundle
F. Coronary sinus
Correct Answers: A, B, C, D, E. [CORRECT]
Rationale: The cardiac conduction system includes the SA node (primary pacemaker), AV node
(delay and gatekeeper), Bundle of His (proximal His-Purkinje system), bundle branches (left
anterior/posterior fascicles and right bundle branch), Purkinje fibers (terminal conduction
network), and Bachmann's bundle (interatrial conduction pathway from right to left atrium). The
coronary sinus is a venous structure draining the heart and is not part of the electrical conduction
system.
Q9: In a patient with left bundle branch block (LBBB), which ECG characteristic is typically
observed?
A. RSR' pattern in V1 with wide S waves in lateral leads
B. Broad monophasic R waves in lateral leads (I, aVL, V5-V6) with QS or rS in V1
C. Normal QRS duration <120 ms
D. Right axis deviation
Correct Answer: B. [CORRECT]
Rationale: LBBB produces delayed and abnormal activation of the left ventricle, resulting in
broad, notched, or slurred R waves in lateral leads (I, aVL, V5-V6) and deep QS or rS complexes
in right precordial leads (V1-V2) due to the loss of normal left-to-right septal activation. QRS
duration is prolonged ≥120 ms. The RSR' pattern in V1 is characteristic of right bundle branch
block.
Q10: Which factor primarily determines the strength of myocardial contraction (contractility)
independent of preload and afterload?
A. Heart rate
B. Calcium availability within the myocyte
C. Blood volume
D. Systemic vascular resistance
Correct Answer: B. [CORRECT]
IBHRE CCDS Certification Exam Actual Exam
2026/2027 | Certified Cardiac Device Specialist
Complete Practice Test with Verified Answers |
Already Graded A+ (BRAND NEW!!)
SECTION 1: BASIC CARDIAC PHYSIOLOGY & ANATOMY (15 Questions)
Q1: During phase 0 of the cardiac action potential in ventricular myocytes, which ion movement
is primarily responsible for depolarization?
A. Potassium efflux
B. Sodium influx
C. Calcium influx
D. Chloride influx
Correct Answer: B. [CORRECT]
Rationale: Phase 0 (rapid depolarization) in ventricular myocytes is caused by fast sodium
channels opening, allowing rapid sodium influx down the electrochemical gradient. This
generates the upstroke of the action potential. Calcium influx is responsible for phase 2 (plateau),
not phase 0.
Q2: The sinoatrial (SA) node is located at which anatomical site?
A. Junction of the superior vena cava and right atrial appendage
B. Coronary sinus ostium
C. Interventricular septum
D. Left atrial roof near the pulmonary veins
Correct Answer: A. [CORRECT]
Rationale: The SA node is located at the junction of the superior vena cava and the right atrial
appendage in the crista terminalis region. This position allows it to serve as the primary
pacemaker, receiving autonomic innervation and maintaining the highest intrinsic automaticity
(60-100 bpm) under normal conditions.
,2
Q3: Which ECG finding is characteristic of complete (third-degree) AV block?
A. Prolonged PR interval with dropped beats
B. AV dissociation with independent atrial and ventricular rates
C. Narrow QRS complex with 1:1 AV conduction
D. Gradual PR prolongation until a beat is dropped
Correct Answer: B. [CORRECT]
Rationale: Third-degree AV block is defined by complete failure of atrial impulses to conduct to
the ventricles, resulting in AV dissociation. The atria and ventricles beat independently at their
own rates (atrial rate typically 60-100 bpm, ventricular escape rate 20-40 bpm for junctional or
20-40 bpm for ventricular escape), with no consistent relationship between P waves and QRS
complexes.
Q4: In the His-Purkinje system, which structure represents the only normal electrical connection
between atria and ventricles?
A. Bundle of Kent
B. Accessory pathway
C. Bundle of His
D. Mahaim fibers
Correct Answer: C. [CORRECT]
Rationale: The Bundle of His is the proximal portion of the His-Purkinje system and represents
the only normal electrical pathway connecting the atrial conduction system to the ventricular
myocardium. It emerges from the AV node, penetrates the central fibrous body, and bifurcates
into the right and left bundle branches. Accessory pathways (Kent bundles, Mahaim fibers) are
abnormal connections.
Q5: During phase 4 of the pacemaker action potential, which ionic current is responsible for
spontaneous diastolic depolarization?
A. IKr (rapid delayed rectifier potassium current)
B. If (funny current) - mixed Na+/K+ influx
C. ICa,L (L-type calcium current)
D. Ito (transient outward potassium current)
Correct Answer: B. [CORRECT]
,3
Rationale: Phase 4 spontaneous depolarization in SA nodal cells is mediated primarily by the
"funny current" (If), a mixed sodium-potassium inward current activated by hyperpolarization.
This current slowly depolarizes the membrane potential toward threshold, creating automaticity.
The If current is modulated by autonomic tone (sympathetic stimulation increases If,
parasympathetic decreases it).
Q6: Which hemodynamic consequence is most likely when transitioning from atrial fibrillation
to normal sinus rhythm in a patient with a dual-chamber pacemaker programmed to VVI mode?
A. Improved cardiac output due to rate regularization
B. Loss of atrial contribution to ventricular filling (atrial kick)
C. Decreased systemic vascular resistance
D. Reduced mitral regurgitation
Correct Answer: B. [CORRECT]
Rationale: In VVI mode, the pacemaker paces and senses only in the ventricle with no atrial
tracking. Even when sinus rhythm is restored, the ventricle is paced asynchronously to atrial
activity, resulting in loss of AV synchrony and the atrial contribution to ventricular filling (atrial
kick), which comprises 15-25% of cardiac output, particularly important in patients with reduced
ventricular compliance.
Q7: The normal intrinsic rate of the AV node under conditions of complete SA node failure is
approximately:
A. 20-40 beats per minute
B. 40-60 beats per minute
C. 60-80 beats per minute
D. 80-100 beats per minute
Correct Answer: B. [CORRECT]
Rationale: The AV node exhibits secondary pacemaker activity with an intrinsic escape rate of
40-60 beats per minute. This is slower than the SA node (60-100 bpm) but faster than ventricular
escape rhythms (20-40 bpm). The hierarchical nature of cardiac pacemakers ensures that if the
primary pacemaker fails, a subsidiary pacemaker can maintain cardiac output, albeit at a slower
rate.
SATA Question - Cardiac Conduction System:
Q8: Which structures are part of the normal cardiac conduction system? Select all that apply.
A. Sinoatrial (SA) node
, 4
B. Atrioventricular (AV) node
C. Bundle of His
D. Purkinje fibers
E. Bachmann's bundle
F. Coronary sinus
Correct Answers: A, B, C, D, E. [CORRECT]
Rationale: The cardiac conduction system includes the SA node (primary pacemaker), AV node
(delay and gatekeeper), Bundle of His (proximal His-Purkinje system), bundle branches (left
anterior/posterior fascicles and right bundle branch), Purkinje fibers (terminal conduction
network), and Bachmann's bundle (interatrial conduction pathway from right to left atrium). The
coronary sinus is a venous structure draining the heart and is not part of the electrical conduction
system.
Q9: In a patient with left bundle branch block (LBBB), which ECG characteristic is typically
observed?
A. RSR' pattern in V1 with wide S waves in lateral leads
B. Broad monophasic R waves in lateral leads (I, aVL, V5-V6) with QS or rS in V1
C. Normal QRS duration <120 ms
D. Right axis deviation
Correct Answer: B. [CORRECT]
Rationale: LBBB produces delayed and abnormal activation of the left ventricle, resulting in
broad, notched, or slurred R waves in lateral leads (I, aVL, V5-V6) and deep QS or rS complexes
in right precordial leads (V1-V2) due to the loss of normal left-to-right septal activation. QRS
duration is prolonged ≥120 ms. The RSR' pattern in V1 is characteristic of right bundle branch
block.
Q10: Which factor primarily determines the strength of myocardial contraction (contractility)
independent of preload and afterload?
A. Heart rate
B. Calcium availability within the myocyte
C. Blood volume
D. Systemic vascular resistance
Correct Answer: B. [CORRECT]
