NHA CPCT/A EKG EXAM 2026/2027 | 100% Correct Answers
with Complete Solutions | EKG Monitoring & Rhythm
Interpretation | CPCT/A Certification | Pass Guaranteed - A+
Graded
Domain 1: Cardiac Anatomy & Physiology (15 Questions)
Q1: A patient asks the CPCT why the EKG shows electrical activity before the heart
actually pumps blood. Which explanation is most accurate?
A. "The EKG measures mechanical contraction directly, so they happen simultaneously"
B. "Electrical depolarization triggers mechanical contraction; there's a brief delay
between them"
C. "The EKG only shows valve movements, which occur after electrical activity"
D. "Blood flow creates the electrical signals, so mechanical activity comes first"
Correct Answer: B
Rationale: The cardiac cycle involves electromechanical coupling: electrical
depolarization (shown on EKG) precedes and triggers mechanical contraction. The P
wave (atrial depolarization) occurs before atrial contraction; the QRS complex
(ventricular depolarization) precedes ventricular contraction by approximately 40-60
milliseconds. This delay represents the time for excitation-contraction coupling
(calcium release, cross-bridge formation).
● A is incorrect: The EKG measures electrical activity only, not mechanical
contraction. They are related but not simultaneous; electrical precedes
mechanical.
, ● C is incorrect: EKG does not show valve movements; valves are assessed by
echocardiography or auscultation.
● D is incorrect: This reverses the physiology; electrical activity is intrinsic (SA node
autorhythmicity) and causes mechanical response, not vice versa.
Q2: During an EKG, the CPCT notes the patient has a heart rate of 75 bpm. If the SA
node were to fail, which structure would most likely become the heart's pacemaker?
A. AV node at 40-60 bpm
B. Bundle of His at 60-100 bpm
C. Purkinje fibers at 20-40 bpm
D. Atrial myocardium at 75 bpm
Correct Answer: A
Rationale: The conduction system hierarchy has intrinsic firing rates: SA node (60-100
bpm), AV node (40-60 bpm), Bundle of His (40-60 bpm), and Purkinje fibers (20-40 bpm).
If the SA node fails, the AV node becomes the escape pacemaker at its intrinsic rate of
40-60 bpm. This produces a junctional rhythm with absent or inverted P waves and
narrow QRS complexes.
● B is incorrect: The Bundle of His fires at 40-60 bpm, not 60-100 bpm; 60-100 is
SA node rate.
● C is incorrect: Purkinje fibers are third in hierarchy (20-40 bpm); AV node takes
over before Purkinje activation.
● D is incorrect: Atrial myocardium has no intrinsic pacemaker capability; only
specialized conduction tissue generates spontaneous action potentials.
Q3: The CPCT is reviewing the coronary circulation. Which coronary artery primarily
supplies blood to the SA and AV nodes?
,A. Left anterior descending artery
B. Circumflex artery
C. Right coronary artery (RCA)
D. Left main coronary artery
Correct Answer: C
Rationale: In 85% of people (right-dominant circulation), the right coronary artery (RCA)
supplies the SA node (in 60% of people) and AV node (in 90% of people) via the
posterior descending artery and atrial branches. RCA occlusion can cause bradycardia,
heart blocks, or inferior wall MI with conduction defects.
● A is incorrect: The left anterior descending (LAD) supplies the anterior wall,
anterior septum, and anterior papillary muscle; it does not supply the conduction
nodes.
● B is incorrect: The circumflex artery supplies the lateral wall and left atrium; it
may supply the SA node in 40% of people (left-dominant), but RCA is primary for
AV node.
● D is incorrect: The left main coronary artery is a short trunk that bifurcates into
LAD and circumflex; it does not directly supply nodal tissue.
Q4: A patient has damage to the left bundle branch. Which EKG finding would the CPCT
expect?
A. Narrow QRS complex (<0.12 seconds) with ST elevation
B. Wide QRS complex (≥0.12 seconds) with notched R waves in lateral leads
C. Prolonged PR interval with dropped beats
D. Absent P waves with regular narrow QRS complexes
, Correct Answer: B
Rationale: Left bundle branch block (LBBB) causes delayed left ventricular activation,
producing: QRS duration ≥0.12 seconds (≥3 small squares), broad monophasic R waves
in lateral leads (I, aVL, V5, V6), deep S waves in right precordial leads (V1-V2), and
absent Q waves in lateral leads. The morphology reflects unopposed right ventricular
activation followed by slow left ventricular spread.
● A is incorrect: Narrow QRS indicates normal conduction or supraventricular
origin; LBBB requires wide QRS. ST elevation suggests infarction, not bundle
branch block.
● C is incorrect: Prolonged PR with dropped beats describes second-degree AV
block (Mobitz I or II), not bundle branch block.
● D is incorrect: Absent P waves with narrow QRS describes junctional rhythm;
LBBB has P waves (usually) and wide QRS.
Q5: During the cardiac cycle, which phase corresponds to the T wave on the EKG?
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Correct Answer: C
Rationale: The T wave represents ventricular repolarization (electrical recovery). During
repolarization, the ventricles reset their electrical state, preparing for the next
depolarization. The T wave is upright in most leads because repolarization proceeds
from epicardium to endocardium (opposite of depolarization), creating positive
deflection.
with Complete Solutions | EKG Monitoring & Rhythm
Interpretation | CPCT/A Certification | Pass Guaranteed - A+
Graded
Domain 1: Cardiac Anatomy & Physiology (15 Questions)
Q1: A patient asks the CPCT why the EKG shows electrical activity before the heart
actually pumps blood. Which explanation is most accurate?
A. "The EKG measures mechanical contraction directly, so they happen simultaneously"
B. "Electrical depolarization triggers mechanical contraction; there's a brief delay
between them"
C. "The EKG only shows valve movements, which occur after electrical activity"
D. "Blood flow creates the electrical signals, so mechanical activity comes first"
Correct Answer: B
Rationale: The cardiac cycle involves electromechanical coupling: electrical
depolarization (shown on EKG) precedes and triggers mechanical contraction. The P
wave (atrial depolarization) occurs before atrial contraction; the QRS complex
(ventricular depolarization) precedes ventricular contraction by approximately 40-60
milliseconds. This delay represents the time for excitation-contraction coupling
(calcium release, cross-bridge formation).
● A is incorrect: The EKG measures electrical activity only, not mechanical
contraction. They are related but not simultaneous; electrical precedes
mechanical.
, ● C is incorrect: EKG does not show valve movements; valves are assessed by
echocardiography or auscultation.
● D is incorrect: This reverses the physiology; electrical activity is intrinsic (SA node
autorhythmicity) and causes mechanical response, not vice versa.
Q2: During an EKG, the CPCT notes the patient has a heart rate of 75 bpm. If the SA
node were to fail, which structure would most likely become the heart's pacemaker?
A. AV node at 40-60 bpm
B. Bundle of His at 60-100 bpm
C. Purkinje fibers at 20-40 bpm
D. Atrial myocardium at 75 bpm
Correct Answer: A
Rationale: The conduction system hierarchy has intrinsic firing rates: SA node (60-100
bpm), AV node (40-60 bpm), Bundle of His (40-60 bpm), and Purkinje fibers (20-40 bpm).
If the SA node fails, the AV node becomes the escape pacemaker at its intrinsic rate of
40-60 bpm. This produces a junctional rhythm with absent or inverted P waves and
narrow QRS complexes.
● B is incorrect: The Bundle of His fires at 40-60 bpm, not 60-100 bpm; 60-100 is
SA node rate.
● C is incorrect: Purkinje fibers are third in hierarchy (20-40 bpm); AV node takes
over before Purkinje activation.
● D is incorrect: Atrial myocardium has no intrinsic pacemaker capability; only
specialized conduction tissue generates spontaneous action potentials.
Q3: The CPCT is reviewing the coronary circulation. Which coronary artery primarily
supplies blood to the SA and AV nodes?
,A. Left anterior descending artery
B. Circumflex artery
C. Right coronary artery (RCA)
D. Left main coronary artery
Correct Answer: C
Rationale: In 85% of people (right-dominant circulation), the right coronary artery (RCA)
supplies the SA node (in 60% of people) and AV node (in 90% of people) via the
posterior descending artery and atrial branches. RCA occlusion can cause bradycardia,
heart blocks, or inferior wall MI with conduction defects.
● A is incorrect: The left anterior descending (LAD) supplies the anterior wall,
anterior septum, and anterior papillary muscle; it does not supply the conduction
nodes.
● B is incorrect: The circumflex artery supplies the lateral wall and left atrium; it
may supply the SA node in 40% of people (left-dominant), but RCA is primary for
AV node.
● D is incorrect: The left main coronary artery is a short trunk that bifurcates into
LAD and circumflex; it does not directly supply nodal tissue.
Q4: A patient has damage to the left bundle branch. Which EKG finding would the CPCT
expect?
A. Narrow QRS complex (<0.12 seconds) with ST elevation
B. Wide QRS complex (≥0.12 seconds) with notched R waves in lateral leads
C. Prolonged PR interval with dropped beats
D. Absent P waves with regular narrow QRS complexes
, Correct Answer: B
Rationale: Left bundle branch block (LBBB) causes delayed left ventricular activation,
producing: QRS duration ≥0.12 seconds (≥3 small squares), broad monophasic R waves
in lateral leads (I, aVL, V5, V6), deep S waves in right precordial leads (V1-V2), and
absent Q waves in lateral leads. The morphology reflects unopposed right ventricular
activation followed by slow left ventricular spread.
● A is incorrect: Narrow QRS indicates normal conduction or supraventricular
origin; LBBB requires wide QRS. ST elevation suggests infarction, not bundle
branch block.
● C is incorrect: Prolonged PR with dropped beats describes second-degree AV
block (Mobitz I or II), not bundle branch block.
● D is incorrect: Absent P waves with narrow QRS describes junctional rhythm;
LBBB has P waves (usually) and wide QRS.
Q5: During the cardiac cycle, which phase corresponds to the T wave on the EKG?
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Correct Answer: C
Rationale: The T wave represents ventricular repolarization (electrical recovery). During
repolarization, the ventricles reset their electrical state, preparing for the next
depolarization. The T wave is upright in most leads because repolarization proceeds
from epicardium to endocardium (opposite of depolarization), creating positive
deflection.
