⚡Wolff–Parkinson–White Syndrome & Electrophysiology Study — 20 MCQs
⚡Wolff–Parkinson–White Syndrome & Electrophysiology Study — 20 MCQs
⚡ Wolff–Parkinson–White Syndrome & Electrophysiology Study — 20 MCQs
1. A 21-year-old male with WPW presents with AF and a ventricular rate of 260/min with irregular wide QRS complexes. What is the preferred acute management?
A. IV Procainamide
B. IV Verapamil
C. IV Adenosine
D. DC Shock is contraindicated
**Procainamide** slows conduction in accessory pathway and is preferred. AV nodal blockers are dangerous.
2. The electrophysiologic property of an accessory pathway most predictive of risk of sudden cardiac death is:
A. AP efferent refractory period < 250 ms
B. Antegrade block at baseline
C. Retrograde-only conduction
D. Presence of intermittent pre-excitation
Shortest **pre-excited RR interval during AF** < 250 ms indicates rapid conduction → SCD risk.
3. The ECG feature defining WPW syndrome is:
A. Short PR interval + delta wave
B. Prolonged PR + delta wave
C. Normal PR + wide QRS
D. Isolated wide QRS
WPW = **short PR + delta wave + wide QRS** due to pre-excitation.
4. Orthodromic AVRT in WPW typically shows:
A. Narrow QRS tachycardia
B. Wide QRS regular tachycardia
C. Irregular wide QRS
D. Atrial flutter pattern
Orthodromic AVRT uses AV node antegrade → **narrow QRS**.
5. Which drug is unsafe in pre-excited atrial fibrillation?
A. Amiodarone IV
B. Procainamide
C. Ibutilide
D. Verapamil
AV-nodal blockers (e.g., **Verapamil**) accelerate AP conduction → VF risk.
6. In WPW patients undergoing EPS, the most important measurement for risk stratification is:
A. HV interval
B. SA node recovery time
C. Shortest pre-excited RR interval during AF
D. Ventricular effective refractory period
SPERRI during AF < 250 ms = high-risk, indication for ablation.
7. The most effective definitive therapy for symptomatic WPW is:
A. Beta blockers
B. Radiofrequency ablation
C. Long-term amiodarone
D. Verapamil
**RFA** cures WPW in >95% cases.
8. A left-sided accessory pathway is most effectively mapped during EPS by:
A. His bundle catheter
B. Transseptal mapping or retrograde aortic approach
C. Coronary sinus proximal recordings only
D. Ventricular apex catheter
Left pathways → **CS catheters + transseptal/retrograde mapping**.
9. In antidromic AVRT, the QRS morphology is:
A. Narrow
B. Wide
C. Irregular
D. Alternating narrow & wide
Antidromic = AP antegrade → **wide QRS**.
10. Which accessory pathway location is most common in WPW?
A. Left free wall
B. Right free wall
C. Septal
D. Anteroseptal only
**Left free-wall APs** are most common.
11. Loss of pre-excitation during exercise stress testing in WPW indicates:
A. High-risk pathway
B. Low-risk pathway
C. Need for urgent ablation
D. Unstable pathway
Loss of pre-excitation implies AP cannot conduct rapidly → **low risk**.
12. A delta wave is produced by:
A. Slow AV nodal conduction
B. Early ventricular activation via accessory pathway
C. Ventricular ectopy
D. SA node block
Delta wave = **early ventricular activation** through AP.
13. The ECG sign that suggests a posteroseptal accessory pathway is:
A. Negative delta wave in II, III, aVF
B. Positive delta wave in V1
C. Negative delta wave in V1
D. Bizarre QRS axis
Posteroseptal AP → **negative delta in inferior leads**.
14. In WPW, what is the effect of adenosine during orthodromic AVRT?
A. Terminates tachycardia (AV node dependent)
B. Accelerates AP conduction
C. Causes VT
D. Converts to AF always
Orthodromic AVRT uses AV node → **adenosine terminates**.
15. Which is a known complication of accessory pathway ablation near the septum?
A. AV block
B. LV aneurysm
C. Coronary spasm
D. Aortic dissection
Septal pathways lie close to AV node → risk of **AV block**.
16. A patient with WPW has intermittent pre-excitation. This implies:
A. Dangerous pathway
B. AP has long refractory period
C. Need for urgent EPS
D. High risk during AF
Intermittent pre-excitation → **poor antegrade conduction** → low risk.
17. A delta wave is best seen when the accessory pathway conducts:
A. Retrograde only
B. Antegrade only
C. Both antegrade and retrograde
D. Blocked antegrade
Delta wave occurs with **antegrade** conduction.
18. Which is the gold standard for definitive diagnosis of accessory pathway location?
A. 12-lead ECG only
B. Holter monitor
C. EPS mapping
D. Echocardiography
EPS is the **gold standard** for precise AP localization.
19. In WPW with recurrent symptomatic AVRT, the recommended therapy is:
A. Long-term beta-blockers
B. Sotalol therapy
C. Catheter ablation
D. Digoxin
**Ablation** is curative and first-line for symptomatic AVRT.
20. Which finding suggests a right-sided accessory pathway?
A. Negative delta in V1
B. Positive delta in V1
C. Negative delta in I, aVL
D. Left bundle branch block appearance
**Positive delta in V1** → right-sided pathway.
