ECG ECG in Clinical Practice

Question 1

How does an ECG differ in pediatric patients compared to adults?

Accepted Answer

Children normally have faster heart rates, right axis deviation in infancy, and different normal values for intervals

Answer

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?

Accepted Answer

Continuous ambulatory ECG recording over 24-48 hours to detect intermittent arrhythmias

Answer

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?

Accepted Answer

Increasing heart rate, ST segment changes indicating ischemia, and arrhythmia detection under exertion

Answer

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?

Accepted Answer

They indicate previous myocardial infarction with irreversible tissue death in the affected area

Answer

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25% of R wave height) indicate prior transmural myocardial infarction where dead heart muscle has been replaced by scar tissue, serving as a permanent marker of past heart attack.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?

Accepted Answer

Wide QRS (>120ms) with rsR' pattern in V1 (rabbit ears) and wide S wave in V6

Answer

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.

ECG (Electrocardiogram) Practice Test

ECG (Electrocardiogram) Practice Test

ECG ECG in Clinical Practice