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25% of R wave height) indicate prior transmural myocardial infarction where dead heart muscle has been replaced by scar tissue, serving as a permanent marker of past heart attack.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.
ECG ECG in Clinical Practice 1
How does an ECG differ in pediatric patients compared to adults?