Cardiovascular · Year 1 · from Cardiovascular
Case 1: Wolff-Parkinson-White Syndrome with SVT
Patient Presentation
Demographics: 24-year-old male
Chief Complaint: Sudden onset rapid heartbeat and near-syncope
History of Present Illness: A 24-year-old previously healthy male presents to the emergency department with sudden onset rapid, regular palpitations that began 45 minutes ago while playing basketball. He reports lightheadedness, mild chest discomfort, and feels like his heart is "racing out of his chest." He has had similar but shorter episodes in the past that resolved spontaneously. No prior cardiac history.
Physical Examination:
- Vital Signs: BP 95/62 mmHg, HR 210 bpm (regular), RR 22/min, SpO2 96% on room air
- General: Anxious, diaphoretic
- Cardiovascular: Tachycardic, regular rhythm, no murmurs
- Lungs: Clear bilaterally
Workup
- ECG during tachycardia: Narrow complex regular tachycardia at 210 bpm, no visible P waves
- ECG after conversion: Short PR interval (100 ms), delta wave (slurred upstroke of QRS), wide QRS complex (140 ms)
- Echocardiogram: Normal LV function, no structural abnormalities
- Electrophysiology study: Left lateral accessory pathway identified
Diagnosis
Wolff-Parkinson-White syndrome with orthodromic atrioventricular reentrant tachycardia (AVRT)
Electrophysiology Correlation: WPW syndrome occurs due to an accessory pathway (Bundle of Kent) that bypasses the AV node, creating an anatomical circuit for reentry. The accessory pathway has faster conduction than the AV node and lacks decremental conduction properties. During orthodromic AVRT, the impulse travels down the AV node (anterograde) and returns via the accessory pathway (retrograde), creating a macro-reentrant circuit. The delta wave on resting ECG represents ventricular pre-excitation via the accessory pathway.
Treatment
Acute management:
- Vagal maneuvers (Valsalva, carotid massage) - attempted, unsuccessful
- Adenosine 6 mg IV push - converted to sinus rhythm
- Avoid AV nodal blockers if atrial fibrillation develops (can accelerate conduction down accessory pathway)
Long-term management:
- Catheter ablation of accessory pathway (definitive treatment)
- High success rate (>95%) with low complication risk
- Avoidance of triggers (caffeine, alcohol)
Clinical Image
Image Description: 12-lead ECG demonstrating Wolff-Parkinson-White pattern with characteristic short PR interval (<120 ms) and delta wave (slurred upstroke of QRS complex) representing ventricular pre-excitation through the accessory pathway.
Source: Wikimedia Commons - WPW syndrome ECG License: CC BY-SA 3.0 URL: https://commons.wikimedia.org/wiki/File:WPW_ECG.png