ECG Clinical Applications 2 — Questions and Answers
Question 1: A patient with acute anterior MI develops a new right bundle branch block. Which ECG lead best demonstrates the RBBB pattern?
- Lead I
- Lead V1 (Correct answer)
- Lead aVF
- Lead II
Correct answer: Lead V1
RBBB produces an RSR' (rabbit ears) pattern best seen in V1 with a wide S wave in lead I.
Question 2: A patient presents with syncope. ECG shows a QTc of 520 ms. Which medication is most likely responsible?
- Metoprolol
- Lisinopril
- Amiodarone (Correct answer)
- Aspirin
Correct answer: Amiodarone
Amiodarone prolongs the QT interval significantly and is a common iatrogenic cause of QTc prolongation.
Question 3: An ECG shows ST elevation in leads II, III, and aVF. Which coronary artery is most likely occluded?
- Left anterior descending
- Left circumflex
- Right coronary artery (Correct answer)
- Left main coronary artery
Correct answer: Right coronary artery
ST elevation in inferior leads (II, III, aVF) indicates inferior MI, most commonly due to RCA occlusion.
Question 4: A patient with known COPD shows peaked P waves exceeding 2.5 mm in lead II. This finding is called:
- P mitrale
- P pulmonale (Correct answer)
- Delta wave
- Epsilon wave
Correct answer: P pulmonale
Tall, peaked P waves in lead II (>2.5 mm) indicate right atrial enlargement, termed P pulmonale, commonly seen in chronic lung disease.
Question 5: Which ECG change is most characteristic of hyperkalemia?
- Prominent U waves
- Tall peaked T waves (Correct answer)
- Prolonged QT interval
- ST depression in V4-V6
Correct answer: Tall peaked T waves
Hyperkalemia causes tall, narrow, peaked (tent-shaped) T waves as an early finding due to altered ventricular repolarization.
Question 6: A 60-year-old man has an ECG showing Mobitz Type II block. What is the most appropriate initial management?
- Observation only
- Atropine IV
- Transcutaneous pacing (Correct answer)
- Adenosine IV
Correct answer: Transcutaneous pacing
Mobitz Type II is unpredictable and can progress to complete heart block; transcutaneous pacing is required as a bridge to permanent pacing.
Question 7: An ECG shows diffuse ST elevation with a saddle-back morphology and PR depression in all leads. What is the most likely diagnosis?
- Acute STEMI
- Pericarditis (Correct answer)
- Brugada syndrome
- Takotsubo cardiomyopathy
Correct answer: Pericarditis
Diffuse ST elevation with PR depression in all leads (except aVR) is pathognomonic for acute pericarditis.
ECG Clinical Applications 2
A patient with acute anterior MI develops a new right bundle branch block.
Which ECG lead best demonstrates the RBBB pattern?