CCT - Practice Test UPDATED ACTUAL
Exam Questions And CORRECT Answers
1. Which heart chamber functions to pump deoxygenated blood to the lungs?
a. Right atrium
b. Right ventricle
c. Left atrium
d. Left ventricle - CORRECT ANSWER - 1. B: The right ventricle pumps the
deoxygenated blood it has received from the right atrium to the lungs. The right atrium pumps
deoxygenated blood from the body to the right ventricle. The left atrium pumps oxygenated
blood from the lungs to the left ventricle. The left ventricle pumps oxygenated blood to the body.
2. Which lead is the most affected by respiration?
a. V2
b. V4
c. Lead III
d. Lead I - CORRECT ANSWER - 2. C: Lead III is the most affected by respiration, and
therefore the waveforms may look different depending on the respiratory cycle. Because of this,
a Q wave that only appears in lead III and is not associated with other corresponding changes in
other leads is not significant.
3. Which of the following is the correct sequence by which action potentials are conducted
through the heart?"
a. SA node → AV node → bundle branches → Purkinje fibers
b. Bundle branches → Purkinje fibers → SA node → AV node
c. Purkinje fibers → SA node → bundle branches → AV node
d. AV node → SA node → bundle branches → Purkinje fibers - CORRECT ANSWER - 3.
A: The sequence by which an action potential is conducted through the heart is from the
sinoatrial (SA) node to the atrioventricular (AV) node to the bundle branches and then to the
Purkinje fibers.
,4. What type of heart block is seen in the following electrocardiogram (ECG) strip?"
a. First-degree heart block
b. Second-degree heart block, type 1
c. Second-degree heart block, type 2
d. Third-degree heart block - CORRECT ANSWER - 4. B: The pictured ECG is a second-
degree heart block, type 1. This rhythm is also called Mobitz I or Wenckebach. With this heart
block the PR interval gets longer with each beat until eventually a P wave occurs, but a QRS
does not follow (a beat is skipped). After the skipped beat, the pattern starts over again. A first-
degree heart block occurs when the PR interval is longer than 0.2 seconds, but the PR interval
generally remains constant and the QRS is not dropped. A second-degree heart block, type 2, also
called Mobitz II, is apparent when the QRS suddenly fails to show up after a P wave. A fairly
consistent ratio of P waves to QRS complexes is common, and this rhythm lacks the increasing
PR interval that is seen in the Mobitz I block. A third-degree heart block is also called a complete
heart block and the atria and ventricles beat independently of one another.
5. When calibrating an ECG machine, what is the standard size of the calibration mark
representing the sensitivity of the ECG machine?
a. 5 mm in height
b. 10 mm in height
c. 15 mm in height
d. 20 mm in height - CORRECT ANSWER - 5. B: The calibration mark representing the
sensitivity of the ECG should be 10 mm in height (two large squares). This mark is usually found
on the left side of the page at the beginning of each line of the ECG. When this is set correctly it
means that for every millivolt measured from the patient, a deflection of 10 mm will be recorded
on the trace.
6. Which of the following is the mechanism of action of nitrates?
a. Decrease the responsiveness of heart to the sympathetic nervous system
b. Lower the heart rate
c. Decrease cardiac contractility
d. Dilation of coronary arteries - CORRECT ANSWER - 6. D: Nitrates are useful for the
prevention and treatment of angina. They work by dilating the coronary arteries and thus
, increasing the blood flow to the heart. They dilate peripheral veins, and, in higher doses, other
peripheral arteries, which decreases preload and afterload. Beta-blockers decrease the
responsiveness of the heart to the sympathetic nervous system. Calcium channel blockers, beta-
blockers, and other medications decrease cardiac contractility and decrease heart rate.
7. Which phase of the action potential in fast response myocardial tissues consists of rapid
depolarization, with the resting cell being brought to threshold?
a. Phase 0
b. Phase 1
c. Phase 2
d. Phase 3 - CORRECT ANSWER - 7. A: Phase 0 consists of rapid depolarization of the
cell to threshold, which leads to activation of voltage-dependent sodium channels. Phase 1
consists of a slight "notch" of repolarization caused mainly by the activation of transient
potassium currents (potassium leaving the cell) and a corresponding rapid decrease in the sodium
current. Phase 2 is a plateau phase during which "late" calcium, and to a lesser extent sodium,
currents offset the effect of potassium currents and temporarily stabilize the membrane potential.
Phase 3 refers to repolarization and return to resting potential due to increased potassium
currents. Phase 4 is the resting membrane potential.
8. The depolarizing current in pacemaker cells is created primarily by which of the following
ions?
a. Sodium
b. Calcium
c. Potassium
d. Chloride - CORRECT ANSWER - 8. B: The depolarizing current in cardiac pacemaker
cells is carried primarily by relatively slow, inward calcium currents. In most other depolarizing
cells, such as muscle cells, the depolarization is created by fast sodium currents. Potassium plays
a role in repolarization of the cells.
9. Which of the following commonly limits the diagnostic value of Holter monitoring?
a. Patient noncompliance with keeping track of events
b. Lack of continuous monitoring
Exam Questions And CORRECT Answers
1. Which heart chamber functions to pump deoxygenated blood to the lungs?
a. Right atrium
b. Right ventricle
c. Left atrium
d. Left ventricle - CORRECT ANSWER - 1. B: The right ventricle pumps the
deoxygenated blood it has received from the right atrium to the lungs. The right atrium pumps
deoxygenated blood from the body to the right ventricle. The left atrium pumps oxygenated
blood from the lungs to the left ventricle. The left ventricle pumps oxygenated blood to the body.
2. Which lead is the most affected by respiration?
a. V2
b. V4
c. Lead III
d. Lead I - CORRECT ANSWER - 2. C: Lead III is the most affected by respiration, and
therefore the waveforms may look different depending on the respiratory cycle. Because of this,
a Q wave that only appears in lead III and is not associated with other corresponding changes in
other leads is not significant.
3. Which of the following is the correct sequence by which action potentials are conducted
through the heart?"
a. SA node → AV node → bundle branches → Purkinje fibers
b. Bundle branches → Purkinje fibers → SA node → AV node
c. Purkinje fibers → SA node → bundle branches → AV node
d. AV node → SA node → bundle branches → Purkinje fibers - CORRECT ANSWER - 3.
A: The sequence by which an action potential is conducted through the heart is from the
sinoatrial (SA) node to the atrioventricular (AV) node to the bundle branches and then to the
Purkinje fibers.
,4. What type of heart block is seen in the following electrocardiogram (ECG) strip?"
a. First-degree heart block
b. Second-degree heart block, type 1
c. Second-degree heart block, type 2
d. Third-degree heart block - CORRECT ANSWER - 4. B: The pictured ECG is a second-
degree heart block, type 1. This rhythm is also called Mobitz I or Wenckebach. With this heart
block the PR interval gets longer with each beat until eventually a P wave occurs, but a QRS
does not follow (a beat is skipped). After the skipped beat, the pattern starts over again. A first-
degree heart block occurs when the PR interval is longer than 0.2 seconds, but the PR interval
generally remains constant and the QRS is not dropped. A second-degree heart block, type 2, also
called Mobitz II, is apparent when the QRS suddenly fails to show up after a P wave. A fairly
consistent ratio of P waves to QRS complexes is common, and this rhythm lacks the increasing
PR interval that is seen in the Mobitz I block. A third-degree heart block is also called a complete
heart block and the atria and ventricles beat independently of one another.
5. When calibrating an ECG machine, what is the standard size of the calibration mark
representing the sensitivity of the ECG machine?
a. 5 mm in height
b. 10 mm in height
c. 15 mm in height
d. 20 mm in height - CORRECT ANSWER - 5. B: The calibration mark representing the
sensitivity of the ECG should be 10 mm in height (two large squares). This mark is usually found
on the left side of the page at the beginning of each line of the ECG. When this is set correctly it
means that for every millivolt measured from the patient, a deflection of 10 mm will be recorded
on the trace.
6. Which of the following is the mechanism of action of nitrates?
a. Decrease the responsiveness of heart to the sympathetic nervous system
b. Lower the heart rate
c. Decrease cardiac contractility
d. Dilation of coronary arteries - CORRECT ANSWER - 6. D: Nitrates are useful for the
prevention and treatment of angina. They work by dilating the coronary arteries and thus
, increasing the blood flow to the heart. They dilate peripheral veins, and, in higher doses, other
peripheral arteries, which decreases preload and afterload. Beta-blockers decrease the
responsiveness of the heart to the sympathetic nervous system. Calcium channel blockers, beta-
blockers, and other medications decrease cardiac contractility and decrease heart rate.
7. Which phase of the action potential in fast response myocardial tissues consists of rapid
depolarization, with the resting cell being brought to threshold?
a. Phase 0
b. Phase 1
c. Phase 2
d. Phase 3 - CORRECT ANSWER - 7. A: Phase 0 consists of rapid depolarization of the
cell to threshold, which leads to activation of voltage-dependent sodium channels. Phase 1
consists of a slight "notch" of repolarization caused mainly by the activation of transient
potassium currents (potassium leaving the cell) and a corresponding rapid decrease in the sodium
current. Phase 2 is a plateau phase during which "late" calcium, and to a lesser extent sodium,
currents offset the effect of potassium currents and temporarily stabilize the membrane potential.
Phase 3 refers to repolarization and return to resting potential due to increased potassium
currents. Phase 4 is the resting membrane potential.
8. The depolarizing current in pacemaker cells is created primarily by which of the following
ions?
a. Sodium
b. Calcium
c. Potassium
d. Chloride - CORRECT ANSWER - 8. B: The depolarizing current in cardiac pacemaker
cells is carried primarily by relatively slow, inward calcium currents. In most other depolarizing
cells, such as muscle cells, the depolarization is created by fast sodium currents. Potassium plays
a role in repolarization of the cells.
9. Which of the following commonly limits the diagnostic value of Holter monitoring?
a. Patient noncompliance with keeping track of events
b. Lack of continuous monitoring
