ECG ECG in Clinical Practice 1 — Questions and Answers
Question 1: How does an ECG differ in pediatric patients compared to adults?
- Children normally have faster heart rates, right axis deviation in infancy, and different normal values for intervals (Correct answer)
- Pediatric ECGs are identical to adult ECGs
- Children always have abnormal ECGs
- ECG is not used for pediatric patients
Correct answer: Children normally have faster heart rates, right axis deviation in infancy, and different normal values for intervals
Pediatric ECGs have age-dependent normal values: faster resting heart rates, right axis deviation in neonates (transitioning to normal axis), shorter intervals, and different voltage criteria for hypertrophy.
Question 2: What is Holter monitoring?
- Continuous ambulatory ECG recording over 24-48 hours to detect intermittent arrhythmias (Correct answer)
- A one-time resting ECG
- An exercise stress test
- An echocardiogram procedure
Correct answer: Continuous ambulatory ECG recording over 24-48 hours to detect intermittent arrhythmias
Holter monitoring provides continuous ECG recording during normal daily activities for 24-48 hours (or longer with event recorders), capturing intermittent arrhythmias that might not appear during a brief in-office ECG.
Question 3: What ECG changes are expected during an exercise stress test?
- Increasing heart rate, ST segment changes indicating ischemia, and arrhythmia detection under exertion (Correct answer)
- No ECG changes should occur during exercise
- The ECG should show decreasing heart rate
- Only blood pressure changes are monitored
Correct answer: Increasing heart rate, ST segment changes indicating ischemia, and arrhythmia detection under exertion
Exercise stress testing monitors ECG for ischemic changes (ST depression >1mm), arrhythmias, and blood pressure response during graded exercise to evaluate for coronary artery disease and exercise-induced arrhythmias.
Question 4: What is the significance of pathological Q waves on an ECG?
- They indicate previous myocardial infarction with irreversible tissue death in the affected area (Correct answer)
- They are always a normal finding
- They indicate electrolyte imbalance
- They only appear during exercise
Correct answer: They indicate previous myocardial infarction with irreversible tissue death in the affected area
Pathological Q waves (>1mm wide, >25% of R wave height) indicate prior transmural myocardial infarction where dead heart muscle has been replaced by scar tissue, serving as a permanent marker of past heart attack.
Question 5: How does right bundle branch block (RBBB) appear on an ECG?
- Wide QRS (>120ms) with rsR' pattern in V1 (rabbit ears) and wide S wave in V6 (Correct answer)
- Narrow QRS with tall R waves
- Absent P waves
- ST elevation in all leads
Correct answer: Wide QRS (>120ms) with rsR' pattern in V1 (rabbit ears) and wide S wave in V6
RBBB shows widened QRS >120ms, an rsR' (M-shaped) pattern in V1-V2, and a wide, slurred S wave in leads I and V6, reflecting delayed right ventricular depolarization.
Question 6: What does an ECG technologist do when encountering a life-threatening rhythm?
- Immediately alert the supervising physician or activate the emergency response system per facility protocol (Correct answer)
- Continue recording without interruption
- Wait until the recording is complete before acting
- Attempt to treat the patient independently
Correct answer: Immediately alert the supervising physician or activate the emergency response system per facility protocol
When a life-threatening rhythm is identified (VF, VT, asystole, complete heart block), the technologist must immediately alert the physician or activate the emergency response system while maintaining patient safety.
