CET Emergency Cardiac Monitoring 3 — Questions and Answers
Question 1: The Brugada pattern on an ECG is characterized by:
- ST depression in V1–V3 with right bundle branch block
- Coved-type ST elevation in V1–V2 with RBBB morphology (Correct answer)
- Delta waves and shortened PR in V1–V2
- ST elevation in V4–V6 with LBBB
Correct answer: Coved-type ST elevation in V1–V2 with RBBB morphology
The classic Brugada pattern shows a coved-type (downsloping) ST elevation ≥2 mm in V1–V2 with an incomplete or complete RBBB appearance.
Question 2: During an emergency, a patient develops third-degree AV block. The MOST reliable backup pacemaker in this setting originates from the:
- SA node
- AV node
- Bundle of His
- Purkinje fibers or ventricular myocardium (Correct answer)
Correct answer: Purkinje fibers or ventricular myocardium
In complete heart block with no conduction through the AV node, an escape rhythm arises from ventricular tissue (Purkinje fibers) at a rate of 20–40 bpm.
Question 3: A patient receiving IV amiodarone has a QTc of 560 ms on telemetry. The ECG technician should:
- Continue monitoring without action
- Immediately notify the nurse or physician (Correct answer)
- Recalibrate the monitor and repeat the ECG
- Obtain a 12-lead ECG and continue monitoring
Correct answer: Immediately notify the nurse or physician
A QTc ≥500 ms significantly increases the risk of torsades de pointes and requires immediate clinical notification.
Question 4: Which of the following best describes 'demand' pacemaker function during emergency monitoring?
- Paces at a fixed rate regardless of intrinsic rhythm
- Paces only when the heart rate falls below a programmed rate (Correct answer)
- Paces only in response to P waves
- Paces continuously at the maximum programmed rate
Correct answer: Paces only when the heart rate falls below a programmed rate
A demand pacemaker senses intrinsic cardiac activity and delivers a pacing stimulus only when the native rate drops below the programmed lower rate limit.
Question 5: On a monitor, a patient shows a regular wide-complex tachycardia at 150 bpm. A useful bedside clue that favors VT over SVT with aberrancy is:
- Narrow QRS in limb leads only
- AV dissociation visible on the rhythm strip (Correct answer)
- Heart rate exactly 150 bpm
- Positive concordance in precordial leads alone
Correct answer: AV dissociation visible on the rhythm strip
AV dissociation — P waves marching independently of QRS complexes — strongly supports ventricular tachycardia as the diagnosis.
Question 6: Which lead placement error would cause the P wave to appear inverted in lead I?
- RA and LA electrodes reversed (Correct answer)
- RL and LL electrodes reversed
- V1 placed too high on the chest
- LA and LL electrodes reversed
Correct answer: RA and LA electrodes reversed
Reversing the right arm (RA) and left arm (LA) electrodes inverts the polarity of lead I, causing the P wave and QRS to appear negative in that lead.
Question 7: During emergency monitoring of a post-cardiac arrest patient, the ECG shows R-on-T phenomenon. This is clinically significant because it:
- Indicates normal sinus rhythm restoration
- Can trigger ventricular fibrillation (Correct answer)
- Represents bundle branch block recovery
- Confirms successful defibrillation
Correct answer: Can trigger ventricular fibrillation
R-on-T occurs when a premature ventricular beat falls on the vulnerable period of the T wave, which can precipitate ventricular fibrillation.
CET Emergency Cardiac Monitoring 3
The Brugada pattern on an ECG is characterized by: