CCT - Certified Cardiographic Technician Exam — Questions and Answers

Question 1: Which ECG finding is characteristic of hypercalcemia?

Shortened QT interval (Correct answer)
Widened QRS
Prolonged QT interval
Peaked T waves

Correct answer: Shortened QT interval

Elevated calcium shortens the ST segment and therefore the QT interval, because calcium affects plateau-phase duration of the action potential.

Question 2: On the ECG, a junctional escape rhythm typically presents with which rate and P wave pattern?

Rate 100-150 bpm with absent P waves
Rate 40-60 bpm; P waves absent, inverted (retrograde) before or after QRS, or hidden within the QRS, with narrow QRS morphology (Correct answer)
Rate 20-40 bpm with wide QRS and inverted T waves
Rate 60-100 bpm with normal upright P waves and normal PR interval

Correct answer: Rate 40-60 bpm; P waves absent, inverted (retrograde) before or after QRS, or hidden within the QRS, with narrow QRS morphology

The AV junction (His bundle area) has an intrinsic escape rate of 40-60 bpm. Junctional beats conduct to the ventricles normally via the His-Purkinje system (narrow QRS), but P waves are absent or retrograde (inverted in II, III, aVF).

Question 3: A technician notices the QRS complex is predominantly positive in lead aVR on a routine ECG. This finding most likely indicates:

Right ventricular hypertrophy
Anterior myocardial infarction
Normal variant in elderly patients
Right arm and left arm lead reversal artifact (Correct answer)

Correct answer: Right arm and left arm lead reversal artifact

A predominantly positive QRS in aVR, which is always normally negative, is a classic indicator of right arm/left arm lead reversal.

Question 4: A Certified Cardiographic Technician (CCT) is preparing a patient for a 12-lead ECG. The patient has a hairy chest. Which of the following is the most appropriate action to ensure good electrode contact and a clear tracing?

Apply extra conductive gel over the hair to improve the signal.
Shave or clip small areas of hair where the electrodes will be placed. (Correct answer)
Press the electrodes down firmly over the hair.
Place the electrodes on the patient's back instead of the chest.

Correct answer: Shave or clip small areas of hair where the electrodes will be placed.

Dense chest hair can interfere with the adhesion of ECG electrodes and the quality of the electrical signal. To ensure a clear and accurate tracing, small areas where the electrodes are to be placed should be clipped or shaved to allow for direct skin contact.

Question 5: Beta-blockers (Class II antiarrhythmics) produce which primary ECG effect?

Shortened PR interval
Widened QRS
ST elevation
Prolonged PR interval and slowed heart rate (Correct answer)

Correct answer: Prolonged PR interval and slowed heart rate

Beta-blockers slow AV nodal conduction, prolonging the PR interval, and decrease the overall heart rate by reducing sympathetic drive.

Question 6: A patient with Parkinson's disease undergoing an ECG is most likely to exhibit which type of artifact?

Somatic tremor artifact due to involuntary muscle movement (Correct answer)
60 Hz AC artifact due to medication infusion pumps
Motion artifact from voluntary repetitive movements
Wandering baseline due to diaphoresis

Correct answer: Somatic tremor artifact due to involuntary muscle movement

Parkinson's disease causes involuntary resting tremors that appear as somatic tremor artifact on the ECG tracing.

Question 7: A patient's 12-lead ECG shows a short PR interval (<120 ms), delta wave, and wide QRS. This triad defines:

Wolff-Parkinson-White (WPW) syndrome pre-excitation pattern (Correct answer)
First-degree AV block
Hyperkalemia
Left bundle branch block

Correct answer: Wolff-Parkinson-White (WPW) syndrome pre-excitation pattern

The WPW pre-excitation pattern consists of a short PR interval (accessory pathway bypasses AV node), a delta wave (initial slow ventricular activation via the pathway), and a widened QRS.

Question 8: A technician is performing an ECG on a morbidly obese patient and finds it difficult to identify the sternal angle. What is the best approach to locating the correct intercostal spaces?

Estimate placement based on visual inspection of the chest shape
Ask the patient which area of the chest feels most central
Place electrodes at equal-distance intervals across the chest
Palpate the sternum from the top to find the manubriosternal junction (sternal angle/angle of Louis) and count ribs methodically from that landmark (Correct answer)

Correct answer: Palpate the sternum from the top to find the manubriosternal junction (sternal angle/angle of Louis) and count ribs methodically from that landmark

The sternal angle (angle of Louis) is a palpable bony landmark at the junction of the manubrium and sternal body that marks the 2nd rib. Counting down from this point provides accurate intercostal space identification regardless of body habitus.

Question 9: Which class of antiarrhythmic drugs works primarily by blocking sodium channels and is known to widen the QRS complex?

Class III (potassium channel blockers)
Class II (beta-blockers)
Class IV (calcium channel blockers)
Class I (sodium channel blockers) (Correct answer)

Correct answer: Class I (sodium channel blockers)

Class I antiarrhythmics (e.g., flecainide, quinidine) block fast sodium channels, slowing conduction and widening the QRS complex.

Question 10: When monitoring a patient on quinidine therapy, a CCT should be most alert to which dangerous ECG change?

S1Q3T3 pattern
QT interval exceeding 500 ms (Correct answer)
PR shortening below 100 ms
T-wave inversion in V1 only

Correct answer: QT interval exceeding 500 ms

Quinidine prolongs the QT interval, and a QTc above 500 ms significantly increases the risk of quinidine syncope caused by torsades de pointes.

Question 11: What action should a CCT technician take if they observe that the ECG technician's copy of the tracing shows a technically poor-quality recording due to significant artifact?

Document the artifact as the patient's clinical finding
Send the poor-quality tracing and add a verbal note to the physician
Repeat the ECG after addressing the artifact source before sending the tracing for physician interpretation (Correct answer)
Send the tracing without comment since the physician can filter out artifacts mentally

Correct answer: Repeat the ECG after addressing the artifact source before sending the tracing for physician interpretation

A technically poor-quality ECG should be repeated after correcting the artifact source before submission for clinical interpretation, because artifact can mimic or obscure real findings, potentially leading to diagnostic error.

Question 12: What is the correct intercostal space and anatomical location for electrode V4?

4th intercostal space at the left sternal border
5th intercostal space at the anterior axillary line
5th intercostal space at the midclavicular line (Correct answer)
4th intercostal space at the right sternal border

Correct answer: 5th intercostal space at the midclavicular line

V4 is placed at the 5th intercostal space in the midclavicular line (the line descending vertically from the midpoint of the clavicle). This landmark must be correctly identified before placing V5 and V6.

Question 13: What is the purpose of the Wilson Central Terminal in ECG recording?

It amplifies the ECG signal to improve readability
It is the ground electrode that prevents electrical shock to the patient
It creates a reference zero potential by connecting the right arm, left arm, and left leg electrodes through resistors, serving as the negative reference for unipolar leads (Correct answer)
It filters out low-frequency baseline wander from the ECG signal

Correct answer: It creates a reference zero potential by connecting the right arm, left arm, and left leg electrodes through resistors, serving as the negative reference for unipolar leads

The Wilson Central Terminal (WCT) connects the RA, LA, and LL limb electrodes through high-value resistors to create a theoretical zero potential reference point, which serves as the negative reference for the six unipolar precordial leads (V1-V6) and the augmented limb leads.

Question 14: Which of the following ECG findings is the hallmark characteristic of Third-Degree Atrioventricular (AV) Block?

Complete AV dissociation with atrial rate faster than ventricular rate (Correct answer)
A heart rate consistently below 40 bpm with narrow QRS complexes
A constant PR interval with intermittently dropped QRS complexes
Progressively lengthening PR interval until a QRS is dropped

Correct answer: Complete AV dissociation with atrial rate faster than ventricular rate

Third-degree, or complete, AV block is defined by the complete absence of conduction between the atria and ventricles. This results in AV dissociation, where the P waves (atrial activity) and QRS complexes (ventricular activity) are independent of each other, with the atrial rate typically being faster than the ventricular escape rate.

Question 15: Which symptom reported by a patient during stress testing is considered an anginal equivalent that should prompt test termination?

Bilateral leg fatigue without other symptoms
Mild shortness of breath that resolves with slightly reduced workload
Jaw or left arm discomfort concurrent with ischemic ECG changes (Correct answer)
Sweating at peak exercise without symptoms

Correct answer: Jaw or left arm discomfort concurrent with ischemic ECG changes

Jaw pain and left arm discomfort are classic anginal equivalents — manifestations of myocardial ischemia that do not present as typical chest pain. When these occur alongside ischemic ECG changes, the test should be stopped.

Question 16: Ventricular fibrillation (VF) appears as which pattern on the ECG?

Sawtooth waves at 300 bpm with regular QRS complexes
Absent electrical activity (flat line) on all leads
Regular wide QRS complexes at 150-250 bpm with uniform morphology
Completely chaotic, irregular, undulating waveforms with no identifiable QRS complexes, P waves, or T waves at an indeterminate rate (Correct answer)

Correct answer: Completely chaotic, irregular, undulating waveforms with no identifiable QRS complexes, P waves, or T waves at an indeterminate rate

VF produces completely disorganized electrical activity with chaotic, irregular waveforms of varying amplitude and frequency, with no recognizable QRS complexes, P waves, or T waves — the heart is in electrical chaos and not pumping.

Question 17: Which kind of heart block can be noticed in the electrocardiogram (ECG) strip below?

Second-degree heart block, type 1 (Correct answer)
Second-degree heart block, type 2
First-degree heart block
Third-degree heart block

Correct answer: Second-degree heart block, type 1

A first-degree heart block occurs when the PR interval is longer than 0.2 seconds, but the PR interval typically remains constant and the QRS is not dropped. The pictured ECG is a second-degree heart block, type 1. This rhythm is also known as 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. This rhythm lacks the rising PR interval seen in the Mobitz I block and has a fairly constant ratio of P waves to QRS complexes. The atria and ventricles beat independently during a third-degree heart block, which is also known as a complete heart block.

Question 18: Which skin preparation technique is MOST effective in reducing ECG artifact?

Using warming blankets before electrode placement only
Increasing electrode pressure by taping more firmly
Lightly abrading the skin and wiping with alcohol to remove oils and dead cells (Correct answer)
Applying extra electrode gel without cleaning the skin

Correct answer: Lightly abrading the skin and wiping with alcohol to remove oils and dead cells

Lightly abrading the skin and wiping with alcohol removes dead skin cells and oils, significantly reducing impedance and improving electrode contact quality.

Question 19: What is pacemaker failure to capture?

The pacemaker fires (spike visible) but does not depolarize the myocardium (no QRS follows) (Correct answer)
The pacemaker senses intrinsic beats correctly but does not pace
The pacemaker fires too slowly, below the programmed rate
The pacemaker does not fire at all, producing no spikes

Correct answer: The pacemaker fires (spike visible) but does not depolarize the myocardium (no QRS follows)

Failure to capture occurs when a pacemaker spike is visible on the ECG but is not followed by a QRS complex (or P wave for atrial pacing), meaning the electrical stimulus failed to depolarize the myocardium.

Question 20: During the Bruce protocol, a patient achieves 85% of their age-predicted maximum heart rate without symptoms or ECG changes. How is this test best interpreted?

The test is non-diagnostic because the patient did not develop symptoms
The test is positive for ischemia because of the high heart rate achieved
The test is diagnostic — the patient achieved target heart rate without evidence of ischemia (Correct answer)
The test should be repeated immediately at a higher workload

Correct answer: The test is diagnostic — the patient achieved target heart rate without evidence of ischemia

Achieving 85% or more of the age-predicted maximum heart rate (APMHR) without developing symptoms or significant ECG changes constitutes an adequate and negative stress test, providing diagnostic certainty.

Question 21: A patient presents with a regular narrow-complex tachycardia at 180 bpm. P waves are inverted in leads II, III, aVF and appear just before each QRS with a very short RP interval. What is the most likely diagnosis?

Sinus tachycardia with a prolonged PR interval
Accelerated junctional rhythm
AV nodal reentrant tachycardia (AVNRT) or junctional tachycardia with short VA conduction (Correct answer)
Ventricular tachycardia with retrograde conduction

Correct answer: AV nodal reentrant tachycardia (AVNRT) or junctional tachycardia with short VA conduction

A regular narrow-complex tachycardia at ~180 bpm with retrograde P waves (inverted in inferior leads) immediately before the QRS (very short RP interval, typically < 70 ms) is classic for the slow-fast form of AVNRT.

Question 22: A patient undergoing a pharmacological stress test with dobutamine develops new horizontal ST depression in leads V4-V6. What does this finding indicate?

Right ventricular strain
Myocardial ischemia in the lateral wall distribution (Correct answer)
Normal response to increased heart rate
Digoxin effect

Correct answer: Myocardial ischemia in the lateral wall distribution

New horizontal or downsloping ST depression of ≥1 mm during dobutamine stress in lateral leads suggests inducible ischemia in the lateral wall, typically fed by the left circumflex artery.

Question 23: What is 'pacemaker syndrome,' and in which pacing mode does it most commonly occur?

Failure to capture causing repeated near-syncopal episodes
Oversensing causing the pacemaker to stop working
Infection around the pacemaker generator causing systemic symptoms
Symptoms (fatigue, dizziness, pulsations in neck) caused by loss of AV synchrony, most common with VVI pacing (Correct answer)

Correct answer: Symptoms (fatigue, dizziness, pulsations in neck) caused by loss of AV synchrony, most common with VVI pacing

Pacemaker syndrome describes the hemodynamic and symptomatic consequences of AV dissociation caused by ventricular-only pacing (VVI), where the atria contract against closed AV valves, causing retrograde cannon A waves and reduced cardiac output.

Question 24: A patient with a VVIR pacemaker programmed to 60 bpm shows QRS complexes at a rate of 80 bpm with no pacemaker spikes. What is the most likely explanation?

The patient is experiencing VT
The patient's intrinsic heart rate (80 bpm) exceeds the pacemaker's programmed lower rate (60 bpm), appropriately inhibiting pacing (Correct answer)
The pacemaker battery has failed
The pacemaker is malfunctioning with failure to output

Correct answer: The patient's intrinsic heart rate (80 bpm) exceeds the pacemaker's programmed lower rate (60 bpm), appropriately inhibiting pacing

In demand (inhibited) pacing modes like VVI, if the patient's intrinsic rate exceeds the programmed lower rate, the pacemaker appropriately senses the intrinsic beats and inhibits its output. This is normal pacemaker behavior, not a malfunction.

Question 25: What advantages do thallium stress tests have over regular ECG stress tests?

Is a safer test overall for the patient
More accurately identifies the specific areas of reduced blood flow in the heart (Correct answer)
The test is simpler to perform
More quickly identifies areas of myocardial ischemia in the heart

Correct answer: More accurately identifies the specific areas of reduced blood flow in the heart

Nuclear stress tests, sometimes referred to as thallium stress tests, collect more detailed and precise data than straightforward ECG stress testing. When attempting to gauge the degree of coronary artery disease in a patient with a history of the condition, it is a useful test.

Question 26: A procedure that doesn't require entering the body cavity or puncturing or cutting the skin is:

physical therapy
arthroscopy
invasive
non-invasive (Correct answer)

Correct answer: non-invasive

Non-invasive procedures are diagnostic approaches that don't require skin punctures, incisions, or the insertion of foreign objects or materials into the body.

Question 27: A 60-year-old male is scheduled for a maximal exercise stress test. Using the most common standard formula, what is his age-predicted maximum heart rate (MHR)?

170 bpm
150 bpm
160 bpm (Correct answer)
180 bpm

Correct answer: 160 bpm

The most widely used and simplest formula to estimate maximum heart rate is 220 minus the patient's age. For a 60-year-old patient, the calculation is 220 - 60 = 160 bpm.

Question 28: On a standard ECG tracing, which waveform represents the electrical activation and depolarization of the ventricular myocardium?

T wave
QRS complex (Correct answer)
U wave
P wave

Correct answer: QRS complex

The QRS complex represents the rapid depolarization of the right and left ventricles. This large electrical event triggers the mechanical contraction (systole) of the ventricles. The P wave represents atrial depolarization, and the T wave represents ventricular repolarization.

Question 29: A CCT is preparing a patient for a treadmill stress test. To ensure a high-quality ECG tracing with minimal artifact, what is the most critical preparatory step?

Instructing the patient to grip the handrails tightly
Placing the limb leads on the distal extremities
Abrading the skin at electrode sites (Correct answer)
Ensuring the room is slightly cool

Correct answer: Abrading the skin at electrode sites

Proper skin preparation, which includes cleaning and abrading the stratum corneum, is crucial for reducing skin impedance. Lower impedance allows for a better electrical signal to reach the electrode, significantly minimizing motion and other artifacts that are common during exercise.

Question 30: Which finding during exercise stress testing is an indication for immediate test termination?

A normal increase in heart rate from 70 to 120 bpm
Mild dyspnea that the patient tolerates
A drop in systolic blood pressure of more than 10 mmHg below resting baseline despite increasing workload (Correct answer)
Sinus tachycardia at peak exercise

Correct answer: A drop in systolic blood pressure of more than 10 mmHg below resting baseline despite increasing workload

A drop in systolic blood pressure of more than 10 mmHg below the pre-exercise resting level during increasing workload (exertional hypotension) is an absolute indication for test termination because it suggests severe left ventricular dysfunction or outflow obstruction.

Question 31: What is the purpose of the recovery phase after a stress test?

To monitor for delayed ECG changes and hemodynamic recovery, and ensure patient safety (Correct answer)
To rest the patient before they leave
To re-establish electrode contact that was lost during exercise
To recalibrate the ECG machine

Correct answer: To monitor for delayed ECG changes and hemodynamic recovery, and ensure patient safety

The recovery phase is a critical monitoring period where delayed ST changes or arrhythmias may appear, and where hemodynamic parameters (heart rate, blood pressure) return to baseline, confirming the patient is stable to leave.

Question 32: What is meant by 'poor R-wave progression' (PRWP) in the precordial leads?

The R wave decreases from V4 to V6
The R wave is absent only in V1
The P waves fail to maintain consistent morphology across leads
The R wave fails to increase in amplitude across V1-V4, or the transition zone (R=S) occurs later than V4 (Correct answer)

Correct answer: The R wave fails to increase in amplitude across V1-V4, or the transition zone (R=S) occurs later than V4

Poor R-wave progression describes the ECG finding where R waves do not progressively increase in amplitude from V1 through V4 as expected, or where the transition from predominantly negative to predominantly positive QRS occurs later than normal (after V4).

Question 33: Which of the following heart conditions is brought on by the parasympathetic nervous system's actions?

Decreased rate of SA node pacing (Correct answer)
Increased rate of conduction
Greater force of contraction
Decreased diastolic filling time

Correct answer: Decreased rate of SA node pacing

The cardiac inhibitory effects of the parasympathetic nervous system include decreased SA node pacing, decreased conduction, and lower contraction force. The sympathetic nervous system generates an increase in contraction force and rate of conduction. By stimulating the sympathetic nervous system, the heart would contract more quickly, which would shorten the diastolic filling time.

Question 34: An ECG rhythm strip from a patient with a pacemaker shows distinct pacing spikes that are not followed by any electrical activity (neither a P wave nor a QRS complex). This finding is best described as which type of pacemaker malfunction?

Failure to capture (Correct answer)
Oversensing
Undersensing
Failure to pace

Correct answer: Failure to capture

Failure to capture occurs when the pacemaker delivers an electrical stimulus (the spike), but the stimulus is insufficient to depolarize the myocardium. As a result, no P wave or QRS complex is generated after the spike.

Question 35: What ECG features differentiate right bundle branch block (RBBB) from left bundle branch block (LBBB)?

RBBB: QRS < 0.10 s; LBBB: QRS > 0.14 s
Both: identical QRS morphology, distinguished only by axis
RBBB: broad R in lateral leads; LBBB: RSR' in V1
RBBB: RSR' (rabbit ears) in V1 with wide S in lateral leads; LBBB: broad monophasic R in lateral leads with QS/rS in V1 (Correct answer)

Correct answer: RBBB: RSR' (rabbit ears) in V1 with wide S in lateral leads; LBBB: broad monophasic R in lateral leads with QS/rS in V1

The classic RBBB pattern is RSR' (M-shaped 'rabbit ears') in V1 with a wide terminal S wave in lateral leads (I, V5, V6). LBBB shows a broad, notched R in lateral leads with a deep negative QS or rS complex in V1.

Question 36: What blood pressure response during exercise stress testing is considered normal?

Blood pressure does not change during exercise in a healthy individual
Both systolic and diastolic BP increase proportionally by 30-40 mmHg
Systolic BP progressively rises 10-50 mmHg above rest; diastolic BP remains unchanged or decreases slightly (Correct answer)
Systolic BP decreases and diastolic BP increases throughout exercise

Correct answer: Systolic BP progressively rises 10-50 mmHg above rest; diastolic BP remains unchanged or decreases slightly

Normally during exercise, systolic blood pressure rises progressively due to increased cardiac output, while diastolic blood pressure remains relatively stable or may decrease slightly due to peripheral vasodilation in exercising muscles.

Question 37: What does 'METs' stand for in the context of exercise stress testing, and what MET level indicates a good functional capacity?

Metabolic Energy Transfer; ≥15 METs is average
Maximum Exercise Tolerance Score; >5 METs is excellent
Metabolic Equivalents of Task; ≥10 METs indicates good functional capacity with a favorable prognosis (Correct answer)
Myocardial Exercise Testing Standard; >8 METs is poor

Correct answer: Metabolic Equivalents of Task; ≥10 METs indicates good functional capacity with a favorable prognosis

METs (Metabolic Equivalents of Task) measure exercise intensity relative to resting metabolism (1 MET = 3.5 mL O2/kg/min). Achieving ≥10 METs during exercise testing indicates good functional capacity and is associated with a favorable cardiovascular prognosis.

Question 38: Which electrode placement is used for the CM5 lead in Holter monitoring?

Positive electrode at right leg, negative at left leg
Positive electrode at V1, negative at left arm
Positive electrode at manubrium, negative at V5
Positive electrode at V5 position, negative at manubrium (Correct answer)

Correct answer: Positive electrode at V5 position, negative at manubrium

CM5 (Chest-Manubrium lead 5) places the positive electrode at the V5 position on the chest and the negative electrode at the manubrium, which is optimal for detecting ischemic ST changes.

Question 39: What is the normal range for cardiac output at rest in a healthy adult?

10 to 15 liters per minute
4 to 8 liters per minute (Correct answer)
1 to 2 liters per minute
0.5 to 1 liter per minute

Correct answer: 4 to 8 liters per minute

Normal resting cardiac output in a healthy adult is approximately 4-8 liters per minute, calculated as heart rate multiplied by stroke volume (CO = HR × SV).

Question 40: The term for the narrowing of the arteries supplying blood to the heart muscle is:

arterioscerosis
atherosclerosis
peripheral vascular disease
coronary artery disease (Correct answer)

Correct answer: coronary artery disease

cardiovascular disease. Plaque accumulation in the coronary arteries—the arteries that carry blood to the heart—causes coronary artery disease. Deposits of cholesterol make form plaque. Over time, plaque formation causes the interior of the arteries to narrow.

Question 41: A technician acquires a 12-lead ECG and notices the baseline is drifting up and down in a slow, sinusoidal pattern. What is the most likely cause?

Pacemaker malfunction causing intermittent capture
Ventricular bigeminy causing alternating QRS amplitudes
Respiratory motion artifact (breathing-related baseline wander) from electrode movement during respiration (Correct answer)
60 Hz AC electrical interference from nearby equipment

Correct answer: Respiratory motion artifact (breathing-related baseline wander) from electrode movement during respiration

Slow, sinusoidal baseline wander that follows the respiratory cycle is caused by respiratory motion — as the thorax expands and contracts, electrodes shift slightly on the skin, causing a slow, wave-like baseline drift.

Question 42: On ECG, how can you distinguish a right ventricular apex pacemaker from a left ventricular pacemaker (as in CRT devices)?

Both RV and LV pacing show identical QRS morphology
Pacemaker origin cannot be determined from the surface ECG
RV apex pacing shows RBBB morphology; LV pacing shows LBBB morphology
RV apex pacing shows LBBB morphology in precordial leads; LV pacing shows RBBB morphology (Correct answer)

Correct answer: RV apex pacing shows LBBB morphology in precordial leads; LV pacing shows RBBB morphology

RV apex pacing depolarizes the heart starting from the right ventricle and spreading leftward, producing a LBBB-like pattern. LV epicardial pacing (as in CRT) activates the left ventricle first, producing a RBBB-like pattern.

Question 43: When the ventricles are full, the amount of stretch on the heart muscles is referred to as:

afterload
preload (Correct answer)
venous pressure
aortic pressure

Correct answer: preload

Preload, which is referred to most usually as the volume in a ventricle right before the beginning of systole, is defined as the stretch of myocardium or end-diastolic volume of the ventricles.

Question 44: Somatic tremor artifact on an ECG is most likely caused by:

Loose electrode connections
Nearby electrical equipment
Improper lead placement
Patient muscle movement or shaking (Correct answer)

Correct answer: Patient muscle movement or shaking

Somatic tremor artifact results from involuntary patient muscle movement or shaking, producing irregular baseline oscillations on the tracing.

Question 45: A patient scheduled for a resting ECG reports having applied body lotion this morning. What is the best course of action for the CCT?

Apply the electrodes directly over the lotion.
Clean the electrode sites with an alcohol wipe to remove the lotion. (Correct answer)
Wipe the electrode sites with a dry gauze pad before application.
Reschedule the ECG for another day.

Correct answer: Clean the electrode sites with an alcohol wipe to remove the lotion.

Oils, lotions, and sweat on the skin can interfere with electrode adhesion and conductivity, leading to a poor-quality tracing. The proper procedure is to clean the skin at the electrode sites with an alcohol wipe and allow it to dry completely before applying the electrodes.

Question 46: A CCT performing a 12-lead ECG notes a regular wide-complex tachycardia at 180 bpm with AV dissociation. What is the most likely diagnosis?

Ventricular tachycardia (VT) (Correct answer)
Supraventricular tachycardia with aberrant conduction
Sinus tachycardia with bundle branch block
Atrial flutter with 2:1 block

Correct answer: Ventricular tachycardia (VT)

AV dissociation (P waves marching through at a different rate than QRS) in a wide-complex tachycardia is pathognomonic for ventricular tachycardia and should prompt immediate notification.

Question 47: Which of the following best describes the proper technique for safely disconnecting an ECG machine from a patient in a hospital setting?

Remove the ECG cable from the machine first, then pull electrodes off
Pull all electrodes off simultaneously using a fast motion to minimize discomfort
Electrodes should always be cut free with scissors
Remove lead wires from electrodes first, then remove electrodes from the skin, starting with the limbs (Correct answer)

Correct answer: Remove lead wires from electrodes first, then remove electrodes from the skin, starting with the limbs

Lead wires should be detached from electrodes first, then electrodes gently removed from skin (starting with limb leads before precordial), to avoid pulling on the skin or accidentally disconnecting monitoring leads in patients who need continuous monitoring.

Question 48: A 78-year-old sedentary female is referred for a symptom-limited exercise stress test. Which of the following treadmill protocols is most appropriate for this patient?

Modified Bruce Protocol (Correct answer)
Standard Bruce Protocol
Astrand-Ryhming Protocol
Pharmacologic (Dobutamine) Protocol

Correct answer: Modified Bruce Protocol

The Modified Bruce Protocol starts at a lower workload (slower speed and less incline) and has smaller increments between stages compared to the Standard Bruce Protocol. This makes it more suitable for elderly, deconditioned, or post-myocardial infarction patients who may not tolerate the more demanding initial stages of the standard protocol.

Question 49: What is the significance of a 'pacing spike' that falls directly on a T wave in a pacemaker patient?

It is a normal finding during rapid heart rates when the T wave is close to the next QRS
It represents proper atrial pacing triggering ventricular contraction
It represents an R-on-T phenomenon from undersensing that could theoretically induce ventricular fibrillation (Correct answer)
It indicates the pacemaker is functioning normally in the AAI mode

Correct answer: It represents an R-on-T phenomenon from undersensing that could theoretically induce ventricular fibrillation

A pacing spike landing on the T wave (R-on-T phenomenon) results from undersensing — the pacemaker failed to detect the preceding intrinsic QRS and therefore fired at its escape interval, which happened to coincide with the vulnerable period (T wave) of ventricular repolarization.

Question 50: Which chambers of the heart are separated by the interatrial septum?

Right atrium and left atrium (Correct answer)
Left atrium and left ventricle
Right atrium and right ventricle
Right ventricle and left ventricle

Correct answer: Right atrium and left atrium

The interatrial septum is the wall that separates the two atria. It contains the fossa ovalis, a remnant of the foramen ovale from fetal circulation.

Question 51: During routine 12-lead acquisition, the technician notices the P waves in lead aVR are upright and P waves in lead II are inverted. What does this suggest?

Dextrocardia
Lead reversal (right arm and left arm leads swapped) (Correct answer)
Normal ECG pattern
Junctional rhythm

Correct answer: Lead reversal (right arm and left arm leads swapped)

Upright P in aVR and inverted P in II are the opposite of normal and strongly suggest right arm-left arm lead reversal, which is a technical error requiring repeat acquisition.

Question 52: What ECG pattern is characteristic of type I (Wenckebach) second-degree AV block?

Fixed PR interval with random non-conducted P waves
Progressively lengthening PR intervals culminating in a non-conducted P wave (dropped QRS), then the cycle resets (Correct answer)
Alternating conducted and non-conducted P waves with a fixed PR interval in conducted beats
Complete AV dissociation with regular P waves and independent QRS complexes

Correct answer: Progressively lengthening PR intervals culminating in a non-conducted P wave (dropped QRS), then the cycle resets

Mobitz type I (Wenckebach) second-degree AV block shows progressive PR interval lengthening with each beat until one P wave fails to conduct (dropped QRS), then the cycle repeats — the classic 'footprints in the sand' pattern.

Question 53: A patient is being screened for an exercise stress test. Which of the following conditions, if present and symptomatic, represents an absolute contraindication to proceeding with the test?

History of stable angina
Severe aortic stenosis (Correct answer)
Previous coronary artery bypass surgery
Controlled hypertension

Correct answer: Severe aortic stenosis

Symptomatic severe aortic stenosis is an absolute contraindication for exercise stress testing. Exertion in these patients can critically restrict cardiac output, leading to syncope, severe ischemia, or sudden cardiac death. The other options are not absolute contraindications.

Question 54: During a treadmill stress test using the Bruce protocol, the first stage requires walking at what speed and grade?

4.2 mph at 16% grade
1.7 mph at 10% grade (Correct answer)
3.4 mph at 14% grade
2.5 mph at 12% grade

Correct answer: 1.7 mph at 10% grade

Stage 1 of the standard Bruce protocol requires walking at 1.7 mph (2.7 km/h) at 10% grade for 3 minutes, equivalent to approximately 5 METs of workload.

Question 55: A 12-lead ECG shows pathological Q waves (>40 ms wide, >25% of R wave height) in leads II, III, and aVF. What do these represent?

Right bundle branch block
Pericarditis
Old inferior myocardial infarction (scar) (Correct answer)
Normal septal depolarization

Correct answer: Old inferior myocardial infarction (scar)

Pathological Q waves in the inferior leads indicate transmural myocardial necrosis in the inferior wall, representing old or evolving inferior MI.

Question 56: What does a 'Duke Treadmill Score' of +5 or greater indicate?

Low risk — annual mortality of less than 1% per year, suggesting the patient has a good prognosis (Correct answer)
Intermediate risk requiring additional imaging
The test was non-diagnostic and should be repeated
High risk — annual mortality greater than 5% per year, requiring urgent intervention

Correct answer: Low risk — annual mortality of less than 1% per year, suggesting the patient has a good prognosis

Duke Treadmill Score ≥ +5 indicates low risk with an estimated annual mortality of less than 1%, indicating a good prognosis. The score incorporates exercise time, ST deviation, and angina.

Question 57: Wandering baseline artifact is most commonly caused by:

60 Hz electrical interference
Reversed limb lead placement
Respiratory movement or poor electrode-skin contact (Correct answer)
Patient talking during recording

Correct answer: Respiratory movement or poor electrode-skin contact

Wandering baseline is typically caused by respiratory movement or poor electrode-skin contact, making the baseline drift rhythmically up and down.

Question 58: Which ECG finding is pathognomonic for Wolff-Parkinson-White (WPW) syndrome during sinus rhythm?

Long PR interval with normal QRS morphology
Short PR interval (< 0.12 sec) plus a delta wave (slurred QRS onset) plus wide QRS (Correct answer)
Right bundle branch block pattern with RSR' in V1
Sawtooth flutter waves with regular ventricular response

Correct answer: Short PR interval (< 0.12 sec) plus a delta wave (slurred QRS onset) plus wide QRS

The ECG triad of WPW syndrome during sinus rhythm is: short PR interval (<0.12 sec), delta wave (slurred initial QRS deflection from pre-excitation), and widened QRS complex — all resulting from early ventricular activation through the accessory pathway.

Question 59: When is it appropriate to activate the ECG machine's built-in artifact filters?

Whenever the cardiologist requests a filtered tracing after the fact
Only when proper technique cannot eliminate the artifact, and filter use must be documented (Correct answer)
Only for exercise stress testing, never for resting ECGs
Routinely on all ECGs to ensure the cleanest possible tracing

Correct answer: Only when proper technique cannot eliminate the artifact, and filter use must be documented

Filters should only be used as a last resort when technique cannot resolve artifact, and their use must be documented because filters can alter waveform morphology and potentially mask diagnostic findings.

Question 60: Which lead is considered the best single-lead view for detecting atrial activity and identifying P-wave morphology?

I
V5
aVR
V1 (Correct answer)

Correct answer: V1

Lead V1 sits directly over the right atrium and provides the clearest biphasic P wave, making it ideal for identifying atrial activity, flutter waves, and P-wave morphology.

Question 61: A technician observes a 'wandering baseline' on the ECG tracing, where the isoelectric line slowly moves up and down. Which of the following is a common cause of this artifact?

AC electrical interference.
Incorrect paper speed.
Expired electrode gel.
Patient's respiratory movements. (Correct answer)

Correct answer: Patient's respiratory movements.

A wandering baseline is often caused by patient movement, including the rise and fall of the chest during normal breathing. It can also be caused by poor electrode contact or loose electrodes.

Question 62: While reviewing a 24-hour Holter recording, a technician notes several periods of significant baseline wander and artifact, making interpretation difficult. Which of the following is a common cause of this type of artifact in an ambulatory setting?

Patient sleeping in a cold room.
Poor electrode-to-skin contact. (Correct answer)
Interference from a nearby cell phone.
Low battery power in the monitor.

Correct answer: Poor electrode-to-skin contact.

Poor electrode adhesion or contact with the skin is a very common cause of baseline wander and artifact on both resting and ambulatory ECGs. Patient movement, sweat, or inadequate skin preparation can cause the electrodes to lift slightly, disrupting the stable electrical connection needed for a clean tracing.

Question 63: What are the ECG criteria for left bundle branch block (LBBB)?

QRS ≥ 0.12 seconds; broad monophasic R in lateral leads (I, aVL, V5-V6); rS or QS pattern in right precordial leads (V1-V2); absence of septal Q waves in lateral leads (Correct answer)
QRS < 0.12 seconds; tall R waves in V1 and V2
QRS ≥ 0.12 seconds; RSR' (rabbit ears) pattern in V1; wide S waves in lateral leads
QRS ≥ 0.12 seconds; delta wave; short PR interval

Correct answer: QRS ≥ 0.12 seconds; broad monophasic R in lateral leads (I, aVL, V5-V6); rS or QS pattern in right precordial leads (V1-V2); absence of septal Q waves in lateral leads

LBBB criteria: QRS ≥ 0.12 seconds (complete LBBB), broad, notched or monophasic R in leads I, aVL, V5-V6, with no septal Q waves, and a deep rS or QS complex in V1-V2.

Question 64: During a resting ECG, a patient continues to shiver despite being asked to relax. What is the most likely artifact that will result, and how can it be minimized?

Motion artifact; strap the patient's limbs to the table
Muscle tremor artifact (rapid, irregular oscillations obscuring the baseline); warm the patient with a blanket and re-attempt (Correct answer)
60 Hz interference; disconnect all IV pumps
Wandering baseline; have the patient breathe faster

Correct answer: Muscle tremor artifact (rapid, irregular oscillations obscuring the baseline); warm the patient with a blanket and re-attempt

Shivering produces rapid, irregular, high-frequency muscle potentials that overlay the ECG baseline (somatic tremor artifact). Warming the patient with a blanket to stop shivering is the most effective solution.

Question 65: In Einthoven's triangle, which statement correctly describes the relationship between leads I, II, and III?

All three leads are independent with no mathematical relationship
Lead I = Lead II + Lead III
Lead III = Lead I + Lead II
Lead II = Lead I + Lead III (Einthoven's Law) (Correct answer)

Correct answer: Lead II = Lead I + Lead III (Einthoven's Law)

Einthoven's Law states that at any given moment, the voltage in Lead II equals the sum of Lead I and Lead III (II = I + III). This mathematical relationship is the basis of the bipolar limb lead system.

Question 66: Which ECG machine filter setting is designed specifically to reduce low-frequency baseline wander?

Notch filter (60 Hz)
Low-pass filter (e.g., 40 Hz cutoff)
High-pass filter (e.g., 0.5 Hz cutoff) (Correct answer)
Band-reject filter centered at 50 Hz

Correct answer: High-pass filter (e.g., 0.5 Hz cutoff)

A high-pass filter blocks signals below its cutoff frequency (such as 0.5 Hz), eliminating low-frequency baseline wander while allowing cardiac signals to pass.

Question 67: Which precordial lead is typically located at the 4th intercostal space, right sternal border?

V1 (Correct answer)
V2
V4
V3

Correct answer: V1

V1 is placed at the 4th intercostal space at the right sternal border. It provides a view of the right side of the heart, the interventricular septum, and is particularly useful for identifying right bundle branch block and P wave morphology.

Question 68: Which of the following best describes how nitrates work?

Lower the heart rate
Decrease cardiac contractility
Decrease the responsiveness of heart to the sympathetic nervous system
Dilation of coronary arteries (Correct answer)

Correct answer: Dilation of coronary arteries

Nitrates are helpful in the diagnosis, treatment, and prevention of angina. They function by widening the coronary arteries, improving the heart's blood flow. They reduce preload and afterload by widening peripheral veins and, at higher doses, other peripheral arteries. Beta-blockers reduce the heart's sympathetic nervous system response. Beta-blockers, calcium channel blockers, and other drugs lower heart rate and reduce cardiac contractility.

Question 69: A CCT observes a rhythm strip where the PR interval progressively lengthens for three consecutive beats, followed by a P wave that is not followed by a QRS complex. This pattern then repeats. How should this rhythm be identified?

First-Degree AV Block
Third-Degree AV Block
Mobitz I Second-Degree AV Block (Wenckebach) (Correct answer)
Mobitz II Second-Degree AV Block

Correct answer: Mobitz I Second-Degree AV Block (Wenckebach)

The classic finding for Mobitz I Second-Degree AV Block, also known as Wenckebach phenomenon, is a progressive prolongation of the PR interval until a P wave is blocked and a QRS complex is 'dropped'. The cycle then typically resets.

Question 70: A patient's ECG strip shows a regular rhythm with a rate of 45 bpm. The QRS complexes are wide (0.14 seconds), and there are no discernible P waves associated with the QRS complexes. Which of the following rhythms is most likely represented?

Idioventricular rhythm (Correct answer)
Sinus bradycardia with bundle branch block
Third-degree AV block with a junctional escape
Junctional escape rhythm

Correct answer: Idioventricular rhythm

Idioventricular rhythm is characterized by a regular, slow ventricular rate (typically 20-40 bpm, but sometimes up to 50), wide QRS complexes (≥0.12s), and the absence of associated P waves. It acts as a safety mechanism when higher pacemakers fail.

Question 71: Which layer of the heart wall is responsible for the contractile function of the heart?

Pericardium
Myocardium (Correct answer)
Endocardium
Epicardium

Correct answer: Myocardium

The myocardium is the middle muscular layer of the heart wall composed of cardiac muscle cells (cardiomyocytes) that are responsible for generating the force needed to pump blood.

Question 72: What is the correct protocol for verifying patient identity before performing an ECG?

Use two patient identifiers, such as asking the patient to state their full name and date of birth, then compare with the order/wristband (Correct answer)
Check the patient's room number as the primary identifier
Ask the patient 'Are you [patient name]?' as a single identifier check
Rely on the nurse's verbal confirmation of the patient's identity

Correct answer: Use two patient identifiers, such as asking the patient to state their full name and date of birth, then compare with the order/wristband

The Joint Commission requires at least two patient identifiers (name and date of birth, or name and medical record number) before any procedure. This prevents wrong-patient errors.

Question 73: A CCT is reviewing an ECG strip that shows a regular vertical spike immediately preceding each P wave, followed by a normal QRS complex. The patient's heart rate is 70 bpm. Which of the following is the most accurate interpretation?

Failure to capture
Atrial paced rhythm (Correct answer)
Ventricular paced rhythm
Dual-chamber paced rhythm

Correct answer: Atrial paced rhythm

This ECG demonstrates a normally functioning atrial pacemaker. The pacemaker spike initiates atrial depolarization, creating the P wave. The impulse then travels normally through the AV node and ventricles, resulting in a native QRS complex.

Question 74: To obtain a standard 12-lead ECG, how many electrodes are placed on the patient?

12
15
10 (Correct answer)
6

Correct answer: 10

A standard 12-lead ECG provides 12 different views of the heart's electrical activity, but it is recorded using only 10 electrodes: four limb electrodes (one on each arm and leg) and six precordial (chest) electrodes.

Question 75: Which ECG pattern is described as diffuse concave ('saddle-back') ST elevation in most leads with PR depression, without reciprocal changes?

Brugada syndrome
STEMI
Early repolarization variant
Pericarditis (Correct answer)

Correct answer: Pericarditis

Acute pericarditis causes diffuse concave ST elevation and PR depression (especially in II and aVF) in most leads without the reciprocal depression seen in STEMI.

Question 76: To reduce somatic tremor artifact in an anxious or cold patient, the technician should FIRST:

Increase the recording speed to 50 mm/sec
Reassure the patient, ensure warmth, and allow time to relax before recording (Correct answer)
Apply additional electrodes in parallel to average the signal
Immediately activate the artifact filter on the ECG machine

Correct answer: Reassure the patient, ensure warmth, and allow time to relax before recording

Addressing patient comfort and anxiety through reassurance and warmth reduces muscle tension at its source before resorting to technical workarounds.

Question 77: A 12-lead ECG shows ST elevation in V1-V2, deep S waves in I, and right axis deviation. Which condition does this pattern suggest?

Right ventricular hypertrophy (RVH) or strain (Correct answer)
Left ventricular hypertrophy
Lateral MI
Wolff-Parkinson-White syndrome

Correct answer: Right ventricular hypertrophy (RVH) or strain

Right axis deviation, tall R in V1, and deep S in lateral leads are classic features of RVH or right ventricular strain, often seen in pulmonary hypertension or PE.

Question 78: Multifocal atrial tachycardia (MAT) is most commonly associated with which underlying condition?

Hypokalemia without pulmonary disease
Chronic obstructive pulmonary disease (COPD) and other severe pulmonary conditions (Correct answer)
Hypertensive heart disease with left atrial enlargement
Hypothyroidism

Correct answer: Chronic obstructive pulmonary disease (COPD) and other severe pulmonary conditions

MAT is strongly associated with severe pulmonary disease — particularly COPD — and is also seen in critically ill patients with hypoxia, hypercapnia, and theophylline toxicity.

Question 79: True posterior MI is best confirmed on a 12-lead ECG by which finding in the standard leads?

Q waves in II, III, aVF
Tall broad R waves and ST depression in V1-V2 (mirror of posterior STEMI) (Correct answer)
Inverted P waves in V1
ST elevation in V1-V4

Correct answer: Tall broad R waves and ST depression in V1-V2 (mirror of posterior STEMI)

Posterior MI appears as a mirror image in V1-V2: tall, broad R waves (posterior Q equivalents) and ST depression (reciprocal of posterior ST elevation), confirmed with posterior leads V7-V9.

Question 80: On an ECG, what is the characteristic appearance of a pacemaker spike followed by a wide QRS complex?

A broad, notched P wave before a narrow QRS
A tall peaked T wave without a preceding spike
A narrow P wave followed by a normal-width QRS
A thin vertical spike immediately followed by a broad, LBBB-morphology QRS greater than 0.12 seconds (Correct answer)

Correct answer: A thin vertical spike immediately followed by a broad, LBBB-morphology QRS greater than 0.12 seconds

Ventricular paced beats produce a sharp spike (the pacemaker stimulus artifact) immediately followed by a wide QRS complex resembling LBBB morphology, because ventricular activation spreads cell-to-cell rather than via the His-Purkinje system.

Question 81: A patient develops sustained ventricular tachycardia during a stress test. What is the technician's first action?

Have the patient perform a Valsalva maneuver to self-terminate the VT
Continue the test to collect more data about the arrhythmia
Stop the exercise immediately and alert the supervising physician while keeping the patient monitored (Correct answer)
Administer IV lidocaine per standing orders immediately

Correct answer: Stop the exercise immediately and alert the supervising physician while keeping the patient monitored

Sustained VT is an absolute indication to stop exercise immediately. The supervising physician must be notified immediately while the patient is moved to a supine position and continuously monitored for deterioration to VF.

Question 82: A patient develops 3 mm of horizontal ST depression in lead V5 at peak exercise. What does this finding indicate?

A positive stress test result suggesting myocardial ischemia (Correct answer)
Artifact caused by lead movement during exercise
A normal physiologic response to exercise
Pericarditis unmasked by exercise

Correct answer: A positive stress test result suggesting myocardial ischemia

Horizontal or downsloping ST depression of 1 mm or more (measured 60-80 ms after the J point) is the diagnostic criterion for a positive stress test indicating myocardial ischemia. 3 mm is a strongly positive finding.

Question 83: What is the ECG appearance and clinical significance of a 'fusion beat' during ventricular tachycardia?

A fusion beat is a QRS that has fused with a P wave and cannot be measured
A fusion beat indicates complete AV block occurring simultaneously with VT
A QRS morphology intermediate between the sinus QRS and VT QRS, caused by simultaneous activation from both the sinus impulse and the ventricular ectopic focus; it is pathognomonic of VT (Correct answer)
Fusion beats are caused by ventricular pre-excitation in WPW syndrome only

Correct answer: A QRS morphology intermediate between the sinus QRS and VT QRS, caused by simultaneous activation from both the sinus impulse and the ventricular ectopic focus; it is pathognomonic of VT

A fusion beat occurs when a supraventricular impulse and a ventricular ectopic impulse simultaneously activate the ventricles, producing a QRS with intermediate morphology. It is pathognomonic (diagnostic) of VT because it proves AV dissociation — the ventricle was partly captured by a sinus beat.

Question 84: A left bundle branch block (LBBB) on a 12-lead ECG is characterized by which set of findings?

Broad notched R in V1 and deep S in I
Short PR interval and delta wave
Broad notched R in I, aVL, V5-V6 and deep QS or rS in V1, QRS ≥120 ms (Correct answer)
S1Q3T3 pattern

Correct answer: Broad notched R in I, aVL, V5-V6 and deep QS or rS in V1, QRS ≥120 ms

LBBB features include a wide QRS (≥120 ms), broad monophasic R waves in lateral leads (I, aVL, V5-V6), and a deep QS or rS pattern in V1 due to abnormal left ventricular activation.

Question 85: A patient's ECG shows a complete absence of P waves and a regular, narrow-complex rhythm at a rate of 50 beats per minute. Which structure has most likely taken over as the primary pacemaker of the heart?

Purkinje fibers
Atrioventricular (AV) node (Correct answer)
Sinoatrial (SA) node
Bundle of His

Correct answer: Atrioventricular (AV) node

The SA node, the heart's primary pacemaker, normally fires at 60-100 bpm and generates the P wave. Its failure causes a secondary or escape pacemaker to take over. The AV node (or AV junction) has an intrinsic firing rate of 40-60 bpm. When it acts as the pacemaker, it produces a junctional escape rhythm, characterized by a regular, narrow-QRS rhythm without preceding P waves, which matches the scenario. Purkinje fibers have a slower intrinsic rate (20-40 bpm) and produce a wide QRS complex.

Question 86: Which of the following findings is considered an absolute indication to terminate an exercise stress test immediately?

Frequent premature ventricular contractions (PVCs)
Downsloping ST-segment depression of 2 mm
Systolic blood pressure of 210 mmHg
Patient request to stop (Correct answer)

Correct answer: Patient request to stop

According to AHA/ACC guidelines, a patient's request to stop is an absolute indication for terminating the test. While arrhythmias, ST depression, and hypertension are significant and may lead to test termination (often as relative indications), the patient's explicit desire to stop must be honored immediately.

Question 87: A patient's ECG shows two distinct pacing spikes. The first spike is followed by a P wave, and after a short, fixed delay, a second spike appears, followed by a wide QRS complex. This pattern is consistent with which pacing mode?

Atrial pacing (AAI)
Dual-chamber AV sequential pacing (DDD) (Correct answer)
Biventricular pacing (CRT)
Ventricular pacing (VVI)

Correct answer: Dual-chamber AV sequential pacing (DDD)

This describes AV sequential pacing, a function of a dual-chamber pacemaker. The first spike captures the atrium, and the second spike captures the ventricle after a programmed AV delay, mimicking the natural sequence of cardiac contraction.

Question 88: Which of the following ECG findings is most characteristic of a ventricular-paced rhythm originating from a lead in the right ventricle?

A pacing spike followed by a narrow QRS complex (<0.12s)
Pacing spikes that occur randomly without relation to the QRS complex
A pacing spike followed by a P wave
A pacing spike followed by a wide QRS complex with a Left Bundle Branch Block (LBBB) morphology (Correct answer)

Correct answer: A pacing spike followed by a wide QRS complex with a Left Bundle Branch Block (LBBB) morphology

When the right ventricle is paced, the depolarization spreads slowly and abnormally to the left ventricle, bypassing the normal conduction pathway. This results in a wide QRS complex (>0.12s) that typically has a Left Bundle Branch Block (LBBB) appearance.

Question 89: A 55-year-old patient cannot exercise on a treadmill due to severe arthritis. What is the most appropriate alternative to exercise stress testing?

The patient should be referred directly for coronary angiography without stress testing
No stress testing should be performed since exercise is not possible
Rest ECG alone to evaluate for ischemia
Pharmacologic stress testing with vasodilators (adenosine/regadenoson) or dobutamine combined with imaging (Correct answer)

Correct answer: Pharmacologic stress testing with vasodilators (adenosine/regadenoson) or dobutamine combined with imaging

Pharmacologic stress testing using vasodilators (adenosine, dipyridamole, regadenoson) or inotropic agents (dobutamine) combined with nuclear imaging or echocardiography is the established alternative for patients unable to exercise.

Question 90: What is the most important absolute contraindication to exercise stress testing?

Acute myocardial infarction within the previous 2 days (Correct answer)
History of stable angina
Controlled hypertension with resting BP of 150/90
Mild aortic stenosis

Correct answer: Acute myocardial infarction within the previous 2 days

Acute myocardial infarction within 2 days is an absolute contraindication because exercise increases myocardial oxygen demand and can extend the area of infarction or precipitate ventricular arrhythmias in the setting of acute ischemia.

Question 91: Which of the following frequently reduces the utility of Holter monitoring as a diagnostic tool?

Small capacity of recording devices
Transmission of data depends on patient participation
Lack of continuous monitoring
Patient noncompliance with keeping track of events (Correct answer)

Correct answer: Patient noncompliance with keeping track of events

The diagnostic utility of Holter monitoring is severely constrained by patient noncompliance with using event markers and keeping a diary of their symptoms. In order to correlate occurrences with the data gathered, it is crucial for patients to note and document their symptoms. A form of continuous monitoring known as holter monitoring has advantages such as the ability to transmit data without the involvement of the patient and the vast storage capacity of the recording devices.

Question 92: What is the normal R-wave progression across the precordial leads (V1 through V6)?

R wave amplitude is equal in all precordial leads
R wave amplitude progressively increases from V1 to V5/V6, with transition (equal R and S) typically at V3 or V4 (Correct answer)
R wave is absent in V1-V3 and present only in V4-V6
R wave decreases progressively from V1 through V6

Correct answer: R wave amplitude progressively increases from V1 to V5/V6, with transition (equal R and S) typically at V3 or V4

Normal R-wave progression shows a small r in V1 that gradually grows in amplitude through V2, V3, V4, and peaks at V5 or V6, with the R/S ratio transitioning from negative (S>R) to positive (R>S) typically at V3 or V4.

Question 93: Reversal of the left arm (LA) and right arm (RA) electrodes would most likely produce:

Widened QRS complexes in leads II and III only
Inverted QRS complexes in all precordial leads
Inverted P wave and negative QRS in lead I with swapped leads II and III (Correct answer)
A flat line in all limb leads

Correct answer: Inverted P wave and negative QRS in lead I with swapped leads II and III

Swapping LA and RA reverses the polarity of lead I, causing inverted P waves and QRS in lead I, and effectively swaps leads II and III.

Question 94: What is the most common cause of 60 Hz AC interference on an ECG tracing?

Improper grounding or nearby electrical equipment (Correct answer)
Electrode gel drying out
Patient movement during recording
Respiratory variation

Correct answer: Improper grounding or nearby electrical equipment

AC interference at 60 Hz is caused by improper grounding or electromagnetic interference from nearby electrical equipment in the room.

Question 95: The sinoatrial (SA) node is located in which cardiac structure?

AV junction between the atria and ventricles
Right atrium, near the superior vena cava junction (Correct answer)
Interventricular septum
Left atrium, near the pulmonary veins

Correct answer: Right atrium, near the superior vena cava junction

The SA node is located in the posterior wall of the right atrium, near the junction with the superior vena cava, at the sulcus terminalis.

Question 96: A CCT technician is preparing to take an ECG on a female patient. The patient appears anxious and asks if the test requires removing clothing. What is the most appropriate response?

Explain that the chest must be exposed for electrode placement, ensure privacy with draping, and offer to have a same-gender staff member present if the patient prefers (Correct answer)
Tell the patient the request is routine and proceed without addressing the concern
Have the patient undress fully before further discussion
Inform the patient their physician requires full cooperation so the test must proceed immediately

Correct answer: Explain that the chest must be exposed for electrode placement, ensure privacy with draping, and offer to have a same-gender staff member present if the patient prefers

Addressing the patient's anxiety with a clear explanation, offering maximum privacy through proper draping, and offering a same-gender chaperon respects patient dignity and autonomy while maintaining the clinical necessity of the procedure.

Question 97: Which of the following best describes the term 'paroxysmal supraventricular tachycardia' (PSVT)?

A synonym for atrial fibrillation
A specific diagnosis of atrial flutter with 2:1 conduction
Any tachycardia with a rate over 100 bpm
An umbrella term for sudden-onset, regular narrow-complex tachycardias originating above the ventricles, including AVNRT, AVRT, and atrial tachycardia (Correct answer)

Correct answer: An umbrella term for sudden-onset, regular narrow-complex tachycardias originating above the ventricles, including AVNRT, AVRT, and atrial tachycardia

PSVT is a general term for various tachyarrhythmias that originate above the bundle of His, begin and end abruptly (paroxysmal), and usually present as a regular narrow-complex tachycardia — most commonly AVNRT, AVRT (with accessory pathway), and atrial tachycardia.

Question 98: What lead is most susceptible to respiration?

Lead III (Correct answer)
V2
V4
Lead I

Correct answer: Lead III

Since Lead III is the component most impacted by respiration, the waveforms may alter according to the respiratory cycle. A Q wave that only arises in lead III and is not connected to other equivalent changes in other leads is therefore not relevant.

Question 99: A patient undergoing an ECG asks the technician what the test is for. What is the most appropriate response?

Tell the patient it is confidential information that only the doctor can share
Explain that the ECG records the heart's electrical activity and is used by the doctor to evaluate heart rhythm and function, then refer clinical questions to the physician (Correct answer)
Give the patient a detailed interpretation of what the ECG may show
Tell the patient not to worry and that it is routine

Correct answer: Explain that the ECG records the heart's electrical activity and is used by the doctor to evaluate heart rhythm and function, then refer clinical questions to the physician

The technician should provide a clear, accurate description of the procedure (what an ECG does) while appropriately referring clinical interpretation and diagnostic meaning to the ordering physician, respecting the scope of practice.

Question 100: When reviewing a Holter report, the technician sees the notation 'SVE.' What does this abbreviation represent?

Sinus ventricular escape
Subendocardial vascular event
Supraventricular ectopic beat (premature atrial contraction) (Correct answer)
Severe ventricular event

Correct answer: Supraventricular ectopic beat (premature atrial contraction)

SVE stands for supraventricular ectopic beat, which is another term for a premature atrial contraction (PAC) or other ectopic beat originating above the ventricles.

Question 101: Why should limb electrodes be placed on the distal limbs (wrists and ankles) rather than the proximal limbs during a resting ECG?

Distal limbs have less subcutaneous fat, improving conduction
Proximal placement is acceptable but distal is required by regulatory agencies
Distal placement gives a stronger electrical signal
Distal placement reduces muscle artifact from limb movement and provides the correct geometric reference for Einthoven's triangle, consistent with the standard derivation of limb leads (Correct answer)

Correct answer: Distal placement reduces muscle artifact from limb movement and provides the correct geometric reference for Einthoven's triangle, consistent with the standard derivation of limb leads

Distal limb placement minimizes artifact from proximal muscle groups and maintains the standardized geometric relationship that the limb lead derivations (Einthoven's equations) assume. Placing electrodes proximally alters lead axes slightly.

Question 102: Which statement best describes the difference between a 24-hour Holter monitor and an event monitor?

A Holter records continuously for 24-48 hours; an event monitor records only when activated or triggered (Correct answer)
A Holter uses 12 leads; an event monitor uses only 1 lead
A Holter is worn externally; an event monitor is implanted
A Holter records only symptomatic episodes; an event monitor records continuously

Correct answer: A Holter records continuously for 24-48 hours; an event monitor records only when activated or triggered

Holter monitors record continuously for the entire wearing period (24-48 hours), while event monitors (loop recorders) store recordings only when the patient activates them or when an automatic trigger detects an abnormal rhythm.

Question 103: A red blood cell is in the right atrium. Which of the following represents the correct path it will take through the heart's valves to reach the systemic circulation via the aorta?

Tricuspid -> Aortic -> Mitral -> Pulmonic
Mitral -> Aortic -> Tricuspid -> Pulmonic
Pulmonic -> Tricuspid -> Aortic -> Mitral
Tricuspid -> Pulmonic -> Mitral -> Aortic (Correct answer)

Correct answer: Tricuspid -> Pulmonic -> Mitral -> Aortic

Deoxygenated blood flows from the right atrium, through the tricuspid valve to the right ventricle, then through the pulmonic valve to the lungs. Oxygenated blood returns to the left atrium, passes through the mitral valve to the left ventricle, and is finally ejected through the aortic valve into the systemic circulation.

Question 104: A CCT is analyzing a rhythm strip and observes an irregularly irregular rhythm, no discernible P waves, and a fibrillatory baseline. The ventricular rate is 130 bpm. Which of the following is the most likely interpretation?

Atrial Flutter with variable block
Junctional Tachycardia
Atrial Fibrillation (Correct answer)
Multifocal Atrial Tachycardia

Correct answer: Atrial Fibrillation

Atrial Fibrillation is characterized by a chaotic atrial activity leading to an irregularly irregular ventricular response, the absence of P waves, and a fibrillatory baseline on the ECG. [4, 13, 20] Multifocal Atrial Tachycardia would show at least three different P wave morphologies. Atrial Flutter typically has a 'sawtooth' pattern. Junctional Tachycardia is usually regular with absent or inverted P waves.

Question 105: Which type of Holter artifact is most commonly caused by poor electrode-skin contact?

Baseline wander and motion artifact with low-amplitude or flat-line segments (Correct answer)
60 Hz electrical interference appearing as thick baseline
Muscle tremor artifact producing rapid irregular oscillations
Respiratory artifact causing uniform undulation of the baseline

Correct answer: Baseline wander and motion artifact with low-amplitude or flat-line segments

Poor electrode-skin contact causes high impedance at the electrode site, which results in baseline wander, loss of signal (flat line segments), and motion artifact as even minor movement breaks the electrical connection.

Question 106: ST elevation in leads V1-V4 combined with a new right bundle branch block most strongly suggests:

Posterior MI
Pericarditis
Inferior MI
Anterior MI with septal involvement (Correct answer)

Correct answer: Anterior MI with septal involvement

ST elevation in V1-V4 reflects anterior wall STEMI, and a new RBBB can indicate septal involvement, often due to LAD artery occlusion.

Question 107: Which medication can cause a 'Osborn wave' (J wave) pattern on the ECG, though it is more commonly seen with hypothermia?

Amiodarone
Adenosine
Digoxin
Hypothermia alone causes it; no medication independently replicates it consistently (Correct answer)

Correct answer: Hypothermia alone causes it; no medication independently replicates it consistently

Osborn (J) waves are most reliably associated with hypothermia and hypercalcemia; no single medication independently produces this finding with consistency.

Question 108: In third-degree (complete) AV block, what is the key ECG finding that distinguishes it from other forms of AV block?

P waves occur at the same rate as QRS complexes but with very long fixed PR intervals
Complete AV dissociation: P waves and QRS complexes are completely independent with no relationship between them; both have their own regular, independent rates (Correct answer)
Non-conducted P waves occur after every 2 conducted P waves (3:2 block)
PR intervals are progressively lengthening with dropped beats

Correct answer: Complete AV dissociation: P waves and QRS complexes are completely independent with no relationship between them; both have their own regular, independent rates

Third-degree AV block shows complete dissociation between atrial and ventricular activity — P waves march through at the sinus rate while QRS complexes occur at a slower, independent escape rate with no fixed relationship between P waves and QRS complexes.

Question 109: The formula to determine cardiac output, often known as CO, Q, or Qc, is as follows:

SV - HR =CO
SV / HR = CO
SV + HR = CO
SV x HR = CO (Correct answer)

Correct answer: SV x HR = CO

Heart rate (HR) and stroke volume (SV), the amount of blood the heart expels with each beat, are combined to form carbon dioxide (CO).

Question 110: Accelerated idioventricular rhythm (AIVR) differs from VT in what important way?

AIVR has a ventricular rate of 40-100 bpm (slower than VT's >100 bpm) and is generally benign, often seen in reperfusion after MI (Correct answer)
AIVR is faster than VT and more immediately life-threatening
AIVR has a narrower QRS than VT
AIVR always requires immediate defibrillation

Correct answer: AIVR has a ventricular rate of 40-100 bpm (slower than VT's >100 bpm) and is generally benign, often seen in reperfusion after MI

AIVR (rate 40-100 bpm) is a slow ventricular rhythm that does not reach the threshold for VT (>100 bpm). It is characteristically seen during successful reperfusion after MI (a reperfusion arrhythmia) and is generally hemodynamically well-tolerated.

Question 111: Reciprocal ST changes seen in leads I and aVL during an inferior MI indicate:

Normal variant
Posterior extension of the MI
Anterior ischemia
Reciprocal depression confirming inferior STEMI and its territory (Correct answer)

Correct answer: Reciprocal depression confirming inferior STEMI and its territory

ST depression in I and aVL is the expected reciprocal (mirror image) change that confirms inferior STEMI in II, III, aVF, helping to rule out pericarditis or artifact.

Question 112: Left anterior fascicular block (LAFB) produces which characteristic ECG finding?

Wide QRS with left bundle branch block pattern
Left axis deviation with Q waves in inferior leads and prolonged QRS
Left axis deviation (axis between -30 and -90 degrees) with small R in inferior leads, deep S in lateral leads, and normal QRS duration (Correct answer)
Right axis deviation with RBBB morphology

Correct answer: Left axis deviation (axis between -30 and -90 degrees) with small R in inferior leads, deep S in lateral leads, and normal QRS duration

LAFB causes left axis deviation (typically -45° to -90°) due to block of the anterior-superior fascicle of the left bundle, producing a small r followed by a deep S in leads II, III, aVF and a small q followed by a tall R in leads I and aVL, without significant QRS widening.

Question 113: A detached or loose electrode is most likely to produce which type of artifact?

Wandering baseline only in limb leads
Somatic tremor in the affected lead
60 Hz AC interference throughout all leads
A flat line or intermittent signal loss in the affected lead (Correct answer)

Correct answer: A flat line or intermittent signal loss in the affected lead

A loose or detached electrode interrupts the electrical circuit, producing a flat line or intermittent signal dropout in the lead(s) using that electrode.

Question 114: What is the significance of the 'R-on-T' phenomenon in the setting of myocardial infarction?

A PVC that falls on the T wave of the preceding beat can trigger ventricular tachycardia or fibrillation because it occurs during the vulnerable period of ventricular repolarization (Correct answer)
R-on-T only occurs in patients with complete heart block
R-on-T always causes immediate ventricular fibrillation
R-on-T is a normal finding in sinus arrhythmia with no clinical significance

Correct answer: A PVC that falls on the T wave of the preceding beat can trigger ventricular tachycardia or fibrillation because it occurs during the vulnerable period of ventricular repolarization

R-on-T PVCs occur during the vulnerable period (relative refractory period, near the T wave apex) when ventricular muscle cells have varying degrees of repolarization, creating the ideal substrate for reentrant ventricular tachycardia or fibrillation.

Question 115: What is undersensing in a pacemaker, and what ECG pattern does it produce?

The pacemaker cannot capture the myocardium despite sensing correctly
The pacemaker fires at a rate slower than programmed
The pacemaker fails to detect intrinsic cardiac activity and fires at inappropriate times, producing spikes that may fall on T waves (Correct answer)
The pacemaker fires too rapidly, exceeding the programmed rate

Correct answer: The pacemaker fails to detect intrinsic cardiac activity and fires at inappropriate times, producing spikes that may fall on T waves

Undersensing means the pacemaker's sensing circuit fails to detect the patient's own heartbeats, so it fires according to its escape interval as if no intrinsic beat occurred, potentially producing spikes falling on T waves (R-on-T phenomenon).

Question 116: A patient calls the clinic stating that their Holter monitor is beeping intermittently. They have checked the battery, and it appears to be fine. Which of the following is the most likely cause?

A serious arrhythmia has been detected.
The device is operating normally.
A poor or detached electrode connection. (Correct answer)
The monitor's memory is full.

Correct answer: A poor or detached electrode connection.

Intermittent beeping from a Holter monitor, especially when the battery is not the issue, most commonly indicates a problem with the signal acquisition, such as a loose or completely detached electrode. This breaks the electrical circuit, and the device alerts the user to the faulty connection.

Question 117: Which of the following BEST describes the appearance of somatic tremor artifact on an ECG?

Irregular, variable oscillations that can obscure the baseline and waveforms (Correct answer)
A flat isoelectric line in one or more leads
Slow, rhythmic baseline drift correlating with respiration
Regular, fine oscillations at exactly 60 Hz superimposed on the baseline

Correct answer: Irregular, variable oscillations that can obscure the baseline and waveforms

Somatic tremor produces irregular, variable oscillations arising from muscle electrical activity that can obscure and mimic cardiac waveforms.

Question 118: Left axis deviation (LAD) on a 12-lead ECG is defined as the QRS axis falling between:

-30° and -90° (Correct answer)
0° and +90°
+90° and +180°
-90° and -180°

Correct answer: -30° and -90°

Left axis deviation is defined as a QRS axis more negative than -30°, with the range of -30° to -90° representing pathological LAD on a standard 12-lead ECG.

Question 119: A patient undergoing Holter monitoring is instructed to keep a diary. What is the primary purpose of this diary?

To track hours of sleep and rest periods.
To record medication times and dosages.
To correlate the patient's symptoms with the ECG recording. (Correct answer)
To document diet and fluid intake.

Correct answer: To correlate the patient's symptoms with the ECG recording.

The patient diary is a critical component of ambulatory monitoring. By recording the exact time and nature of symptoms like dizziness, palpitations, or chest pain, the physician can correlate these subjective feelings with the objective ECG data recorded at that precise moment.

Question 120: During the recovery phase of an exercise stress test, continuous monitoring of the patient's ECG and vital signs is essential. For how long should this monitoring typically continue?

For at least 6-8 minutes, or until ECG changes and symptoms resolve (Correct answer)
For 1 minute for every stage of exercise completed
Exactly 3 minutes post-exercise
Until the heart rate returns to precisely the resting baseline rate

Correct answer: For at least 6-8 minutes, or until ECG changes and symptoms resolve

The post-exercise recovery period is diagnostically important, as some ischemic changes or arrhythmias may only appear after the exercise has stopped. Standard procedure is to monitor the patient for a minimum of 6-8 minutes, and potentially longer if ECG abnormalities or patient symptoms persist or worsen.

Question 121: What does the T wave on an ECG stand for?

Atrial repolarization
Atrial depolarization
Ventricular depolarization
Ventricular repolarization (Correct answer)

Correct answer: Ventricular repolarization

The ventricles start to repolarize right after the QRS. The faster and concluding portion of the repolarization is represented by the T wave. The P wave is a visual representation of atrial depolarization. The QRS complex symbolizes the depolarization of the ventricles. On the ECG, atrial repolarization is not visible.

Question 122: A 24-hour Holter recording reveals 847 premature ventricular contractions (PVCs). Which characteristic would make this finding most concerning?

PVCs occurring in runs of 3 or more (non-sustained VT) (Correct answer)
PVCs that are unifocal in morphology
PVCs occurring during physical activity
PVCs with a rate of less than 10 per hour

Correct answer: PVCs occurring in runs of 3 or more (non-sustained VT)

Runs of 3 or more consecutive PVCs constitute non-sustained ventricular tachycardia, which is a much more concerning finding associated with higher risk for sustained VT or sudden cardiac death.

Question 123: When is it appropriate to use the 'half-standardization' (5 mm/mV) setting on an ECG machine?

In all pediatric patients as a standard practice
When the patient has a slow heart rate requiring larger waveforms
When QRS complexes are so tall that they overlap adjacent leads, making interpretation impossible at standard gain (Correct answer)
When QRS voltage is very low and complexes are hard to see

Correct answer: When QRS complexes are so tall that they overlap adjacent leads, making interpretation impossible at standard gain

Half-standardization (reducing gain to 5 mm/mV instead of 10 mm/mV) is used when QRS or T wave amplitudes are so large at standard gain that complexes overflow into adjacent channels, overlapping and making the tracing uninterpretable.

Question 124: Which of the following ECG findings is characteristic of a Premature Junctional Contraction (PJC)?

A normal QRS complex preceded by a P wave with a very long PR interval.
An early, wide QRS complex with no preceding P wave.
An early, narrow QRS complex that may have an inverted or absent P wave. (Correct answer)
A late, narrow QRS complex preceded by a different-looking P wave.

Correct answer: An early, narrow QRS complex that may have an inverted or absent P wave.

A Premature Junctional Contraction (PJC) is an early beat originating from the AV junction. Because the impulse travels backward to the atria, the P wave, if visible, will be inverted and can appear before, during (hidden), or after the narrow QRS complex. [2, 18, 26, 31]

Question 125: A properly performed 12-lead ECG should be recorded at what standard paper speed?

25 mm/second (Correct answer)
50 mm/second
10 mm/second
100 mm/second

Correct answer: 25 mm/second

The international standard paper speed for ECG recording is 25 mm/second, which makes each small square (1 mm) equal to 0.04 seconds and each large square (5 mm) equal to 0.20 seconds.

Question 126: On a Holter recording, you observe episodes where the P wave morphology changes beat to beat and the PP intervals vary. What rhythm does this represent?

Normal sinus rhythm with artifact
Wandering atrial pacemaker (Correct answer)
Atrial flutter
Third-degree heart block

Correct answer: Wandering atrial pacemaker

Wandering atrial pacemaker is characterized by at least 3 different P wave morphologies within the same lead and varying PP intervals, reflecting the pacemaker site shifting between the SA node, other atrial locations, and the AV junction.

Question 127: What is the significance of a delta wave on the ECG?

It indicates ventricular pre-excitation via an accessory pathway, as seen in Wolff-Parkinson-White syndrome (Correct answer)
It indicates delayed AV nodal conduction
It is a normal finding in athletes with high vagal tone
It represents normal septal depolarization in the left ventricle

Correct answer: It indicates ventricular pre-excitation via an accessory pathway, as seen in Wolff-Parkinson-White syndrome

A delta wave is a slurred, slowly rising initial deflection of the QRS complex caused by early ventricular activation (pre-excitation) through an accessory pathway that bypasses the AV node, as in Wolff-Parkinson-White (WPW) syndrome.

Question 128: A patient's Holter report notes 'total atrial fibrillation burden: 23%.' What does this mean?

The fibrillation had 23% of normal P wave amplitude
23% of the recording had artifact resembling AFib
The patient was in atrial fibrillation for approximately 23% of the total recording time (Correct answer)
The patient had 23% of their beats as atrial fibrillatory waves

Correct answer: The patient was in atrial fibrillation for approximately 23% of the total recording time

AF burden represents the percentage of total recording time during which the patient was in atrial fibrillation. A 23% burden in a 24-hour recording means approximately 5.5 hours were spent in AFib.

Question 129: A CCT is monitoring a patient whose pacemaker is programmed to a lower rate of 60 bpm. The patient's intrinsic heart rate drops to 50 bpm, but no pacing spikes appear on the ECG, resulting in a long pause. This scenario most likely represents which pacemaker malfunction?

Undersensing
Normal pacemaker function
Oversensing (Correct answer)
Failure to capture

Correct answer: Oversensing

Oversensing occurs when the pacemaker incorrectly interprets electrical signals (e.g., muscle artifact, tall T-waves, or EMI) as intrinsic cardiac activity. This false detection inhibits the pacemaker from delivering a pacing stimulus when it is actually needed, causing a pause or a rate drop.

Question 130: In fast-responding cardiac tissues, which step of the action potential involves rapid depolarization and bringing the resting cell to threshold?

phase 1
phase 3
phase 2
phase 0 (Correct answer)

Correct answer: phase 0

Rapid depolarization of the cell to threshold, which activates voltage-dependent sodium channels, constitutes phase 0.

Question 131: What is the standard size of the calibration mark that indicates the sensitivity of an ECG machine while calibrating one?

5 mm in height
10 mm in height (Correct answer)
20 mm in height
15 mm in height

Correct answer: 10 mm in height

The calibration mark should be 10 mm tall (two huge squares), demonstrating the sensitivity of the ECG. This mark may typically be seen at the start of each line of the ECG on the left side of the page. When this is configured properly, a deflection of 10 mm will be recorded on the trace for each millivolt obtained from the patient.

CCT - Certified Cardiographic Technician Exam

The CCT exam, administered by Cardiovascular Credentialing International (CCI), certifies technicians who perform ECGs, Holter monitoring, and stress testing procedures.

130

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120 min

Time Limit

72%

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