ECG Technologist Prometric exam questions with answers

1. Question 1Ambulatory Monitoring and Exercise Testingmedium

   A patient is undergoing a treadmill test using the standard Bruce protocol. How does the protocol progress?

   1. ASpeed and gradient increase every 3 minutes
   2. BOnly speed increases every 1 minute
   3. COnly gradient increases every 2 minutes
   4. DSpeed and gradient increase every 5 minutes
   Show answer and explanation▾

   Answer: A. Speed and gradient increase every 3 minutes

   The Bruce protocol uses 3-minute stages in which both treadmill speed and gradient increase. Stage 1 begins at 1.7 mph and a 10% gradient. Modified Bruce protocols add gentler early stages for frail or less fit patients.

2. Question 2Ambulatory Monitoring and Exercise Testinghard

   A 60-year-old man is having an exercise test. Using 220 minus age, what is 85% of his age-predicted maximum heart rate?

   1. A128 per minute
   2. B144 per minute
   3. C160 per minute
   4. D136 per minute
   Show answer and explanation▾

   Answer: D. 136 per minute

   Age-predicted maximum heart rate is 220 - 60 = 160 per minute, and 85% of 160 is 136 per minute. Reaching this level is often used to judge whether the test was adequate. Beta blockers can prevent patients from reaching the target.

3. Question 3Arrhythmiasmedium

   A regular narrow complex rhythm at 50 per minute shows inverted P waves in lead II immediately after each QRS complex. What is the most likely rhythm?

   1. ASinus bradycardia
   2. BJunctional rhythm
   3. CSecond-degree AV block
   4. DIdioventricular rhythm
   Show answer and explanation▾

   Answer: B. Junctional rhythm

   A junctional rhythm arises near the AV node at about 40 to 60 per minute, with retrograde P waves that are inverted in the inferior leads and may appear just before, within or after the QRS. Sinus bradycardia has upright P waves in lead II before each QRS. An idioventricular rhythm has broad complexes.

4. Question 4Cardiac Anatomy and Electrophysiologymedium

   A patient with an inferior myocardial infarction develops second-degree AV block. In most people, which artery supplies the AV node, explaining this association?

   1. ARight coronary artery
   2. BLeft anterior descending artery
   3. CLeft circumflex artery
   4. DLeft main stem
   Show answer and explanation▾

   Answer: A. Right coronary artery

   In most people the circulation is right dominant and the AV nodal artery arises from the right coronary artery, which also supplies the inferior wall. Inferior infarction therefore often causes AV block, which is usually transient. The left anterior descending artery supplies the anterior wall and septum.

5. Question 5Pacemakers and Cardiac Deviceseasy

   A pacemaker is programmed in VVI mode. What does this code mean?

   1. APaces atrium, senses ventricle, triggers
   2. BPaces ventricle, senses atrium, inhibits
   3. CPaces both chambers, senses both, dual response
   4. DPaces ventricle, senses ventricle, inhibits
   Show answer and explanation▾

   Answer: D. Paces ventricle, senses ventricle, inhibits

   In the pacing code, the first letter is the chamber paced, the second is the chamber sensed and the third is the response to sensing. VVI paces and senses the ventricle, and a sensed beat inhibits pacing. DDD paces and senses both chambers.

6. Question 6Conduction Disturbancesmedium

   A dizzy 80-year-old has regular P waves at 80 per minute and regular broad QRS complexes at 36 per minute, with no fixed relationship between them. What is the rhythm?

   1. AMobitz type I block
   2. BComplete heart block
   3. C2:1 AV block
   4. DSinus bradycardia
   Show answer and explanation▾

   Answer: B. Complete heart block

   Regular P waves and a slower regular escape rhythm with no relationship between them indicate complete, third-degree, heart block. A broad, slow escape rhythm suggests a ventricular origin and an unstable situation, so the result must be escalated urgently. In 2:1 block, every second P wave is followed by a QRS at a constant PR.

7. Question 7Rate, Rhythm, Axis and Intervalshard

   The measured QT interval is 400 ms and the RR interval is 0.64 seconds. Using the Bazett formula, what is the corrected QT?

   1. A400 ms
   2. B450 ms
   3. C625 ms
   4. D500 ms
   Show answer and explanation▾

   Answer: D. 500 ms

   Bazett formula is QTc = QT / square root of RR (in seconds). The square root of 0.64 is 0.8, so QTc = 400 / 0.8 = 500 ms, which is markedly prolonged and should be reported promptly. Dividing by RR without the square root gives the wrong value of 625 ms.

8. Question 8Rate, Rhythm, Axis and Intervalseasy

   A regular rhythm recorded at 25 mm/s has 4 large squares between consecutive R waves. What is the heart rate?

   1. A60 per minute
   2. B75 per minute
   3. C100 per minute
   4. D120 per minute
   Show answer and explanation▾

   Answer: B. 75 per minute

   At 25 mm/s, 300 large squares pass each minute, so rate = 300 / 4 = 75 per minute. Each large square is 0.2 seconds, so the RR interval is 0.8 seconds, which also gives 75. This method only applies to regular rhythms.

9. Question 9ECG Acquisition, Lead Placement and Artefactsmedium

   A 12-lead ECG shows a negative P wave, QRS and T wave in lead I and an upright P wave and QRS in aVR, while the chest leads look normal. What is the most likely cause?

   1. ADextrocardia
   2. BLeft and right arm electrodes reversed
   3. CLeft arm and left leg electrodes reversed
   4. DLateral myocardial infarction
   Show answer and explanation▾

   Answer: B. Left and right arm electrodes reversed

   Reversing the arm electrodes inverts lead I and swaps aVR with aVL, giving an upright aVR. Normal chest lead progression excludes dextrocardia, which would also show reverse R wave progression. The electrodes should be checked and the ECG repeated.

10. Question 10ECG Acquisition, Lead Placement and Artefactsmedium

    A patient has ST elevation in leads II, III and aVF, and the doctor asks for a recording to look for right ventricular involvement. Which lead is most useful?

    1. AV4R
    2. BV7
    3. CaVL
    4. DV2
    Show answer and explanation▾

    Answer: A. V4R

    V4R, placed in the fifth intercostal space in the right midclavicular line, is the most sensitive lead for right ventricular infarction, which often accompanies inferior infarction. ST elevation of 1 mm or more in V4R supports the diagnosis. V7 is a posterior lead.

11. Question 11Ischaemia, Infarction and Other Waveform Changesmedium

    A 25-year-old with pleuritic chest pain that eases on sitting forward has concave ST elevation in most leads and PR segment depression, with PR elevation in aVR. What is the most likely diagnosis?

    1. AAnterior STEMI
    2. BAcute pericarditis
    3. CPulmonary embolism
    4. DLeft ventricular aneurysm
    Show answer and explanation▾

    Answer: B. Acute pericarditis

    Widespread concave ST elevation not limited to one coronary territory, with PR depression and reciprocal PR elevation in aVR, is typical of acute pericarditis. STEMI shows territorial ST elevation with reciprocal ST depression. The clinical picture of positional pleuritic pain supports pericarditis.

12. Question 12Pacemakers and Cardiac Devicesmedium

    A patient with a ventricular pacemaker has pacing spikes at the programmed rate, but several spikes are not followed by a QRS complex. What does this indicate?

    1. AFailure to capture
    2. BFailure to sense
    3. CNormal inhibition of pacing
    4. DOversensing of T waves
    Show answer and explanation▾

    Answer: A. Failure to capture

    A pacing spike not followed by depolarisation means the stimulus failed to capture the myocardium, for example from lead displacement or a raised threshold. This should be reported urgently, especially if the patient depends on the pacemaker. Failure to sense causes spikes at inappropriate times despite intrinsic beats.

13. Question 13Patient Safety, Emergencies and Infection Controlmedium

    While a technologist records an ECG, the patient becomes unresponsive and the monitor shows a chaotic irregular waveform with no recognisable QRS complexes. What should the technologist do first?

    1. ARepeat the ECG to rule out artefact
    2. BFinish the recording and print it
    3. CCall for help and start CPR
    4. DGive the patient a glass of water
    Show answer and explanation▾

    Answer: C. Call for help and start CPR

    An unresponsive patient with a chaotic waveform is likely in ventricular fibrillation, so the technologist should call for help, start chest compressions and bring a defibrillator. Artefact must not be assumed when the patient is unresponsive. Delays in CPR and defibrillation reduce survival.

14. Question 14Rate, Rhythm, Axis and Intervalsmedium

    A 10-second rhythm strip of an irregular rhythm contains 12 QRS complexes. What is the approximate ventricular rate?

    1. A60 per minute
    2. B84 per minute
    3. C72 per minute
    4. D120 per minute
    Show answer and explanation▾

    Answer: C. 72 per minute

    For irregular rhythms, the number of QRS complexes in a 10-second strip is multiplied by 6, so 12 x 6 = 72 per minute. Methods based on a single RR interval give misleading values when the rhythm is irregular. Atrial fibrillation is a common example.

15. Question 15Rate, Rhythm, Axis and Intervalsmedium

    On a 12-lead ECG, the QRS is mainly positive in lead I and mainly negative in leads II and aVF. What is the cardiac axis?

    1. ANormal axis
    2. BRight axis deviation
    3. CExtreme axis deviation
    4. DLeft axis deviation
    Show answer and explanation▾

    Answer: D. Left axis deviation

    A positive lead I with a negative lead II and aVF places the axis beyond -30 degrees, which is left axis deviation. If lead II were positive with aVF negative, the axis would still be normal. A common cause is left anterior fascicular block.

Last reviewed September 2026. Questions are original and written to the published exam blueprint; they are not taken from any real paper.