Beat Reading Heart Beat Reading 5 — Questions and Answers
Question 1: A patient presents with a slow wide-complex rhythm at 35 bpm following cardiac arrest resuscitation. This is most consistent with:
- Sinus bradycardia
- Accelerated idioventricular rhythm
- Idioventricular (agonal) rhythm (Correct answer)
- Junctional bradycardia
Correct answer: Idioventricular (agonal) rhythm
An idioventricular rhythm at 20-40 bpm with wide bizarre QRS and no P waves is an agonal rhythm seen in severe cardiac compromise.
Question 2: Delta waves on an ECG, combined with a short PR interval and wide QRS, are characteristic of:
- Brugada syndrome
- Wolff-Parkinson-White (WPW) syndrome (Correct answer)
- Long QT syndrome
- Left bundle branch block
Correct answer: Wolff-Parkinson-White (WPW) syndrome
WPW syndrome is caused by an accessory pathway (Bundle of Kent) producing delta waves, a short PR interval, and widened QRS due to pre-excitation.
Question 3: When counting heart rate using the 'big block method' on an ECG, what sequence of numbers is used between consecutive R waves?
- 300, 150, 100, 75, 60, 50 (Correct answer)
- 200, 100, 75, 60, 50, 40
- 300, 200, 150, 100, 75, 60
- 250, 150, 100, 80, 60, 50
Correct answer: 300, 150, 100, 75, 60, 50
The large-block method uses the sequence 300, 150, 100, 75, 60, 50 — counting large squares between R waves and matching to the nearest number.
Question 4: ST depression in leads V1-V4 may be a 'reciprocal change' indicating ST elevation (injury) in which area?
- Anterior wall
- Inferior wall
- Posterior wall (Correct answer)
- Lateral wall
Correct answer: Posterior wall
Posterior MI is recognized on standard ECG as ST depression in V1-V4 (mirror image), since there are no direct posterior leads.
Question 5: A patient's ECG shows an RSR' pattern in V1 and wide S waves in leads I and V6. This pattern indicates:
- Left bundle branch block
- Right bundle branch block (Correct answer)
- Left anterior fascicular block
- Anterior STEMI
Correct answer: Right bundle branch block
Right bundle branch block (RBBB) produces a classic RSR' ('rabbit ears') in V1 and wide, slurred S waves in leads I and V6.
Question 6: Which finding on ECG best indicates pericarditis rather than acute MI?
- ST elevation in a single coronary territory
- Reciprocal ST depression in opposing leads
- Diffuse ST elevation in multiple leads with PR depression (Correct answer)
- New left bundle branch block
Correct answer: Diffuse ST elevation in multiple leads with PR depression
Pericarditis typically causes diffuse (saddle-shaped) ST elevation in most leads and PR-segment depression, unlike the focal territorial pattern of MI.
Question 7: In a patient with a pacemaker, the small vertical spike before each QRS on the ECG represents:
- A PVC artifact
- The pacing stimulus delivered by the pacemaker (Correct answer)
- A bundle branch block conduction delay
- Atrial fibrillation waveform
Correct answer: The pacing stimulus delivered by the pacemaker
The pacemaker spike is a narrow electrical artifact that marks when the pacemaker device fires and stimulates the myocardium.
Beat Reading Heart Beat Reading 5
A patient presents with a slow wide-complex rhythm at 35 bpm following cardiac arrest resuscitation.
This is most consistent with: