EKG Technician — Proficiency Exam

15 questions · pass with 50%

1. Which structure normally sets the heart rate, and at what intrinsic rate?
The AV node at 40 to 60 beats per minuteThe Purkinje fibres at 20 to 40 beats per minuteThe SA node at 60 to 100 beats per minuteThe bundle of His at 80 to 120 beats per minute
2. Why is there a flat PR segment between the P wave and the QRS complex?
The atria are repolarising during that timeThe AV node is deliberately delaying the impulse so the atria can finish emptyingThe recorder pauses briefly between chambersThe ventricles are relaxing after the previous beat
3. A rhythm originates below the bundle branches. What would you expect?
A fast rate with a narrow QRSA normal rate with a tall P waveA slow rate with a wide QRSA fast rate with no T wave
4. Atrial repolarisation does not appear on the ECG because:
The atria do not repolarise electricallyIt is masked by the much larger QRS complexStandard ECG filters remove itIt happens during the T wave and is too slow to record
5. Which coronary artery most commonly supplies the inferior wall and the AV node?
Left anterior descendingLeft circumflexPulmonary arteryRight coronary artery
6. Where exactly does the V4 electrode go?
Fourth intercostal space, left sternal borderFifth intercostal space, midclavicular lineFifth intercostal space, midaxillary lineFourth intercostal space, anterior axillary line
7. A tracing shows a negative P wave, negative QRS and inverted T wave in lead I, but completely normal precordial leads. What is the most likely explanation?
An acute lateral wall problemLeft arm and right arm electrode reversalDextrocardiaA left bundle branch block
8. Which leads view the inferior wall of the heart?
V1 and V2I, aVL, V5 and V6II, III and aVFV3 and V4
9. You place V1 and V2 in the second intercostal space instead of the fourth. What is the likely consequence?
No meaningful change, since the leads are still on the correct sideThe heart rate will read artificially highAn rSr pattern with T wave inversion that falsely mimics anterior diseaseThe limb leads will lose all amplitude
10. Why should the Mason-Likar torso arrangement not be used for a routine resting diagnostic 12-lead?
It is uncomfortable for the patientIt shifts the axis and alters amplitudes compared with true limb placementIt cannot record the precordial leadsIt requires twelve electrodes instead of ten
11. On standard ECG paper, one large box represents how much time?
0.04 seconds0.10 seconds0.20 seconds1.00 second
12. R waves are exactly three large boxes apart in a regular rhythm. What is the heart rate?
150 beats per minute100 beats per minute75 beats per minute60 beats per minute
13. A rhythm is irregularly irregular. Which rate method should you use?
Divide 300 by the number of large boxes between two R wavesCount QRS complexes in a 6-second window and multiply by 10Divide 1500 by the small boxes between the first two R wavesMeasure the PR interval and read it off a conversion table
14. You measure a PR interval of 6 small boxes. What does that represent?
0.12 seconds, which is normal0.24 seconds, which is longer than normal0.06 seconds, which is shorter than normal0.30 seconds, which is normal at slow rates
15. The calibration pulse on your tracing measures 5 mm tall instead of 10 mm. What does this mean?
The paper speed has been changed to 50 mm per secondThe electrodes have poor contactThe machine is running at half standard gain, so amplitudes are half their true sizeThe tracing is unusable and must be discarded

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