CCI CCT EXAM (Cardiovascular Credentialing
International- Certified Cardiographic Technician |
230 Advanced Practice Questions and answers pkus
rationales | latest update
SECTION 1: CARDIAC ANATOMY & PHYSIOLOGY
1. The cardiac conduction system originates at the sinoatrial (SA) node, which is located in the:
A) Left atrium near the pulmonary veins
B) Right atrium near the junction of the superior vena cava (correct answer)
C) Interventricular septum at the bundle of His
D) Right ventricle near the tricuspid valve
Rationale: The SA node is located in the right atrium near the junction of the superior vena cava
and the right atrium. It is the dominant pacemaker of the heart, generating impulses at a rate of
60–100 beats per minute in normal sinus rhythm, and is sometimes called the "pacemaker of the
heart."
2. The normal sequence of cardiac conduction travels in which order?
A) SA node → Bundle of His → AV node → Purkinje fibers → Bundle branches
B) SA node → AV node → Bundle of His → Bundle branches → Purkinje fibers (correct
answer)
C) AV node → SA node → Bundle of His → Purkinje fibers → Bundle branches
D) SA node → Bundle branches → AV node → Bundle of His → Purkinje fibers
Rationale: Normal impulse conduction: SA node → internodal pathways → AV node (normal
delay 0.12–0.20 seconds) → Bundle of His → right and left bundle branches → Purkinje fiber
network → ventricular myocardium. This sequence ensures coordinated atrial contraction
followed by ventricular contraction.
3. The normal intrinsic rate of the AV node (junctional) pacemaker is:
A) 60–100 bpm
, B) 40–60 bpm (correct answer)
C) 20–40 bpm
D) 100–150 bpm
Rationale: The AV node (junctional pacemaker) has an intrinsic rate of 40–60 bpm. The SA
node (60–100 bpm) normally overrides the AV node. The ventricular escape rate is 20–40 bpm.
This hierarchy of pacemakers (overdrive suppression) means the fastest pacemaker controls heart
rate under normal conditions.
4. The "absolute refractory period" in the cardiac cycle refers to the time when:
A) The heart can be stimulated to contract with a very strong stimulus
B) No stimulus, regardless of strength, can produce another action potential (correct
answer)
C) The heart is partially responsive to electrical stimulation
D) The ventricles are relaxing and filling with blood
Rationale: The absolute refractory period corresponds to the QRS complex through
approximately the peak of the T wave. During this period, all fast sodium channels are
inactivated and no stimulus can produce another action potential. This protects against sustained
tetanic contraction that would be fatal.
5. The "relative refractory period" in the cardiac cycle corresponds to which portion of the ECG?
A) The PR interval
B) The QRS complex
C) The downslope of the T wave (correct answer)
D) The U wave
Rationale: The relative refractory period corresponds to the downslope (descending limb) of the
T wave. During this vulnerable period, a sufficiently strong stimulus CAN initiate another action
potential — potentially triggering ventricular fibrillation. The "R-on-T phenomenon" (PVC
falling on T wave) can trigger VF during this period.
6. The coronary arteries originate from the:
A) Pulmonary artery at its bifurcation
B) Aorta just above the aortic valve cusps (sinuses of Valsalva) (correct answer)
C) Left ventricle at the apex
D) Aortic arch distal to the subclavian artery
,Rationale: The right and left coronary arteries originate from the right and left sinuses of
Valsalva (aortic sinuses), respectively, just above the aortic valve leaflets. The coronary arteries
fill primarily during diastole when the aortic valve is closed and the sinuses of Valsalva are not
obscured by valve leaflets.
7. The left anterior descending (LAD) artery supplies blood to the:
A) Posterior wall of the left ventricle and AV node
B) Anterior wall of the left ventricle, anterior two-thirds of the interventricular septum,
and the bundle branches (correct answer)
C) Right ventricle exclusively and the SA node
D) Left lateral wall and posterior left ventricle
Rationale: The LAD (diagonal branches and septal perforators) supplies: anterior LV wall,
anterior 2/3 of septum, apex, right bundle branch, and left anterior fascicle. LAD occlusion
causes anterior MI, often with ST elevation in leads V1-V4. Complete LAD occlusion is called
the "widow maker" due to its severity.
8. The Frank-Starling mechanism states that:
A) Heart rate is the primary determinant of cardiac output
B) The greater the stretch of the myocardial fibers during diastole, the greater the force of
contraction (correct answer)
C) Afterload directly determines stroke volume regardless of preload
D) Sympathetic stimulation is required for normal cardiac function
Rationale: Frank-Starling law: within physiological limits, increased end-diastolic volume
(preload) stretches myocardial fibers, increasing overlap of actin-myosin filaments, which
increases force of contraction and stroke volume. This mechanism allows the heart to
automatically match output to venous return on a beat-by-beat basis.
9. Cardiac output (CO) is calculated as:
A) Stroke volume × Heart rate (correct answer)
B) Heart rate ÷ Stroke volume
C) Blood pressure × Heart rate
D) Stroke volume + Heart rate
, Rationale: CO = SV × HR. Normal CO is approximately 4–8 liters per minute. Normal stroke
volume is approximately 60–100 mL per beat. Normal HR is 60–100 bpm. CO = 70 mL × 72
bpm ≈ 5.04 L/min. Cardiac output is the primary measure of the heart's pumping effectiveness.
10. The action potential of a ventricular myocyte has a characteristic "plateau phase" (Phase 2)
caused by:
A) Rapid influx of sodium ions through fast channels
B) Slow influx of calcium through L-type calcium channels balanced by potassium efflux
(correct answer)
C) Rapid efflux of potassium restoring resting membrane potential
D) Complete closure of all ion channels creating electrical neutrality
Rationale: Phase 2 (plateau phase): slow inward calcium current (L-type Ca²⁺ channels) nearly
balances slow potassium efflux, maintaining the membrane potential near 0 mV for
approximately 200ms. This plateau is unique to cardiac muscle and underlies the long refractory
period. L-type calcium channel blockers affect this phase.
SECTION 2: ECG FUNDAMENTALS & LEAD PLACEMENT
11. In a standard 12-lead ECG, the "limb leads" consist of:
A) Leads V1 through V6 only
B) Leads I, II, III (bipolar) and aVR, aVL, aVF (augmented unipolar) (correct answer)
C) Leads I, II, III, and V1-V4
D) Leads aVR, aVL, aVF, and V1-V3
Rationale: Limb leads: Bipolar (I, II, III) use two electrodes to measure the potential difference
between two limbs. Augmented unipolar (aVR, aVL, aVF) measure electrical potential at one
limb versus the average of the other two limbs. Together, these six leads examine the heart in the
frontal plane.
12. Lead V1 is placed at which anatomical location?
A) Fifth intercostal space, left midaxillary line
B) Fourth intercostal space, right sternal border (correct answer)
C) Fourth intercostal space, left sternal border
D) Fifth intercostal space, midclavicular line
International- Certified Cardiographic Technician |
230 Advanced Practice Questions and answers pkus
rationales | latest update
SECTION 1: CARDIAC ANATOMY & PHYSIOLOGY
1. The cardiac conduction system originates at the sinoatrial (SA) node, which is located in the:
A) Left atrium near the pulmonary veins
B) Right atrium near the junction of the superior vena cava (correct answer)
C) Interventricular septum at the bundle of His
D) Right ventricle near the tricuspid valve
Rationale: The SA node is located in the right atrium near the junction of the superior vena cava
and the right atrium. It is the dominant pacemaker of the heart, generating impulses at a rate of
60–100 beats per minute in normal sinus rhythm, and is sometimes called the "pacemaker of the
heart."
2. The normal sequence of cardiac conduction travels in which order?
A) SA node → Bundle of His → AV node → Purkinje fibers → Bundle branches
B) SA node → AV node → Bundle of His → Bundle branches → Purkinje fibers (correct
answer)
C) AV node → SA node → Bundle of His → Purkinje fibers → Bundle branches
D) SA node → Bundle branches → AV node → Bundle of His → Purkinje fibers
Rationale: Normal impulse conduction: SA node → internodal pathways → AV node (normal
delay 0.12–0.20 seconds) → Bundle of His → right and left bundle branches → Purkinje fiber
network → ventricular myocardium. This sequence ensures coordinated atrial contraction
followed by ventricular contraction.
3. The normal intrinsic rate of the AV node (junctional) pacemaker is:
A) 60–100 bpm
, B) 40–60 bpm (correct answer)
C) 20–40 bpm
D) 100–150 bpm
Rationale: The AV node (junctional pacemaker) has an intrinsic rate of 40–60 bpm. The SA
node (60–100 bpm) normally overrides the AV node. The ventricular escape rate is 20–40 bpm.
This hierarchy of pacemakers (overdrive suppression) means the fastest pacemaker controls heart
rate under normal conditions.
4. The "absolute refractory period" in the cardiac cycle refers to the time when:
A) The heart can be stimulated to contract with a very strong stimulus
B) No stimulus, regardless of strength, can produce another action potential (correct
answer)
C) The heart is partially responsive to electrical stimulation
D) The ventricles are relaxing and filling with blood
Rationale: The absolute refractory period corresponds to the QRS complex through
approximately the peak of the T wave. During this period, all fast sodium channels are
inactivated and no stimulus can produce another action potential. This protects against sustained
tetanic contraction that would be fatal.
5. The "relative refractory period" in the cardiac cycle corresponds to which portion of the ECG?
A) The PR interval
B) The QRS complex
C) The downslope of the T wave (correct answer)
D) The U wave
Rationale: The relative refractory period corresponds to the downslope (descending limb) of the
T wave. During this vulnerable period, a sufficiently strong stimulus CAN initiate another action
potential — potentially triggering ventricular fibrillation. The "R-on-T phenomenon" (PVC
falling on T wave) can trigger VF during this period.
6. The coronary arteries originate from the:
A) Pulmonary artery at its bifurcation
B) Aorta just above the aortic valve cusps (sinuses of Valsalva) (correct answer)
C) Left ventricle at the apex
D) Aortic arch distal to the subclavian artery
,Rationale: The right and left coronary arteries originate from the right and left sinuses of
Valsalva (aortic sinuses), respectively, just above the aortic valve leaflets. The coronary arteries
fill primarily during diastole when the aortic valve is closed and the sinuses of Valsalva are not
obscured by valve leaflets.
7. The left anterior descending (LAD) artery supplies blood to the:
A) Posterior wall of the left ventricle and AV node
B) Anterior wall of the left ventricle, anterior two-thirds of the interventricular septum,
and the bundle branches (correct answer)
C) Right ventricle exclusively and the SA node
D) Left lateral wall and posterior left ventricle
Rationale: The LAD (diagonal branches and septal perforators) supplies: anterior LV wall,
anterior 2/3 of septum, apex, right bundle branch, and left anterior fascicle. LAD occlusion
causes anterior MI, often with ST elevation in leads V1-V4. Complete LAD occlusion is called
the "widow maker" due to its severity.
8. The Frank-Starling mechanism states that:
A) Heart rate is the primary determinant of cardiac output
B) The greater the stretch of the myocardial fibers during diastole, the greater the force of
contraction (correct answer)
C) Afterload directly determines stroke volume regardless of preload
D) Sympathetic stimulation is required for normal cardiac function
Rationale: Frank-Starling law: within physiological limits, increased end-diastolic volume
(preload) stretches myocardial fibers, increasing overlap of actin-myosin filaments, which
increases force of contraction and stroke volume. This mechanism allows the heart to
automatically match output to venous return on a beat-by-beat basis.
9. Cardiac output (CO) is calculated as:
A) Stroke volume × Heart rate (correct answer)
B) Heart rate ÷ Stroke volume
C) Blood pressure × Heart rate
D) Stroke volume + Heart rate
, Rationale: CO = SV × HR. Normal CO is approximately 4–8 liters per minute. Normal stroke
volume is approximately 60–100 mL per beat. Normal HR is 60–100 bpm. CO = 70 mL × 72
bpm ≈ 5.04 L/min. Cardiac output is the primary measure of the heart's pumping effectiveness.
10. The action potential of a ventricular myocyte has a characteristic "plateau phase" (Phase 2)
caused by:
A) Rapid influx of sodium ions through fast channels
B) Slow influx of calcium through L-type calcium channels balanced by potassium efflux
(correct answer)
C) Rapid efflux of potassium restoring resting membrane potential
D) Complete closure of all ion channels creating electrical neutrality
Rationale: Phase 2 (plateau phase): slow inward calcium current (L-type Ca²⁺ channels) nearly
balances slow potassium efflux, maintaining the membrane potential near 0 mV for
approximately 200ms. This plateau is unique to cardiac muscle and underlies the long refractory
period. L-type calcium channel blockers affect this phase.
SECTION 2: ECG FUNDAMENTALS & LEAD PLACEMENT
11. In a standard 12-lead ECG, the "limb leads" consist of:
A) Leads V1 through V6 only
B) Leads I, II, III (bipolar) and aVR, aVL, aVF (augmented unipolar) (correct answer)
C) Leads I, II, III, and V1-V4
D) Leads aVR, aVL, aVF, and V1-V3
Rationale: Limb leads: Bipolar (I, II, III) use two electrodes to measure the potential difference
between two limbs. Augmented unipolar (aVR, aVL, aVF) measure electrical potential at one
limb versus the average of the other two limbs. Together, these six leads examine the heart in the
frontal plane.
12. Lead V1 is placed at which anatomical location?
A) Fifth intercostal space, left midaxillary line
B) Fourth intercostal space, right sternal border (correct answer)
C) Fourth intercostal space, left sternal border
D) Fifth intercostal space, midclavicular line
