Wolff-Parkinson-White Syndrome (WPW)
The most likely diagnosis is E) Wolff-Parkinson-White syndrome (WPW), as the ECG findings of a short PR interval, delta wave, and wide QRS complex are pathognomonic for ventricular pre-excitation via an accessory pathway. 1
Diagnostic Reasoning
The ECG triad presented in this case is diagnostic of WPW pattern:
- Short PR interval (<120 ms) - reflects rapid conduction through the accessory pathway bypassing the AV node
- Delta wave - the characteristic slurring of the initial QRS upstroke caused by early ventricular activation via the accessory pathway
- Wide QRS complex - results from fusion of ventricular activation through both the normal AV node/His-Purkinje system and the accessory pathway 1, 2
Since this patient has documented symptoms (fatigue, palpitations, and angina), this constitutes WPW syndrome rather than isolated asymptomatic pre-excitation. WPW syndrome is specifically defined as the presence of ventricular pre-excitation on ECG plus documented SVT or symptoms consistent with SVT 1.
Why Other Options Are Incorrect
- Long QT syndrome presents with prolonged QT interval, not short PR or delta waves
- Acute pericarditis shows diffuse ST elevation and PR depression, without pre-excitation
- Brugada syndrome demonstrates right bundle branch block pattern with ST elevation in V1-V3, not delta waves
- Myocarditis may show various ECG changes but not the classic pre-excitation pattern
Critical Clinical Considerations
This is a potentially life-threatening condition. The patient's young age (23 years) places him in the highest risk period for sudden cardiac death, which occurs most frequently in the first two decades of life 3. The risk of SCD over 10 years ranges from 0.15% to 0.24%, and tragically, sudden death may be the first presentation in undiagnosed cases 3.
High-Risk Features to Assess
The following factors increase SCD risk 3:
- History of symptomatic tachycardia (present in this patient)
- Multiple accessory pathways
- Shortest pre-excited R-R interval <250 ms during atrial fibrillation
Management Pathway
Immediate referral for electrophysiology study is warranted given symptomatic presentation. The EP study will:
- Characterize the accessory pathway properties
- Localize the pathway for ablation
- Assess risk of rapid anterograde conduction during AF
Catheter ablation is the definitive treatment with high success rates and should be strongly considered, particularly if the pathway demonstrates rapid anterograde conduction capability 3, 2.
Critical Pitfall to Avoid
Never use AV nodal-blocking agents (adenosine, calcium channel blockers, beta-blockers, digoxin) in patients with pre-excited atrial fibrillation, as these can paradoxically accelerate conduction down the accessory pathway and precipitate ventricular fibrillation 3. However, these agents are appropriate for acute treatment of orthodromic AVRT when the patient is hemodynamically stable 3.
For this symptomatic young patient with classic WPW findings, prompt cardiology referral for risk stratification and consideration of catheter ablation is the appropriate next step to prevent potentially fatal arrhythmic complications.