Lown Ganong Levine Syndrome (LGL) AVRT
Related Subjects:
|Wolff-Parkinson White syndrome (WPW) AVRT
|Lown Ganong Levine Syndrome AVRT
|Supraventricular Tachycardia (SVT)
|Atrial Flutter
|Atrial Fibrillation
|Resuscitation - Adult Tachycardia Algorithm
📖 About
- ⚡ Lown–Ganong–Levine (LGL) Syndrome is a rare pre-excitation syndrome associated with atrioventricular re-entry tachycardia (AVRT), similar in concept to Wolff–Parkinson–White (WPW).
- 🧑⚕️ Described in 1952 by Bernard Lown, William Francis Ganong, and Samuel Levine.
- Key ECG feature: short PR interval without delta wave.
🧬 Aetiology & Pathophysiology
- Proposed mechanism: conduction via an accessory pathway (James fiber) connecting the atrium directly to the distal AV node/His bundle.
- This allows impulses to bypass normal AV nodal delay → short PR interval.
- No ventricular pre-excitation (hence no delta wave unlike WPW).
🩺 Clinical Features
- 💓 Palpitations are the most common symptom, usually due to episodes of paroxysmal SVT/AVRT.
- 📉 Mostly benign, but can be complicated by pre-excited atrial fibrillation → rapid conduction to ventricles → risk of ventricular tachycardia (VT) or fibrillation (VF).
- Occasionally detected incidentally on ECG in asymptomatic patients.
🔍 Investigations
- ECG Features:
- Short PR interval (<120 ms).
- Normal/narrow QRS complex (no delta wave).
- Episodes of paroxysmal SVT (AVRT).
- Electrophysiology studies may help confirm accessory pathway conduction.
- Rule out structural heart disease with echocardiography if clinically indicated.
💊 Management
- For AVRT/SVT episodes → follow standard SVT management protocols (vagal manoeuvres, adenosine if safe, etc.).
- ⚠️ In AF with pre-excitation:
- 🚫 Avoid AV nodal blockers (beta-blockers, calcium-channel blockers, digoxin) as they may accelerate conduction via the accessory pathway.
- ✅ Use Amiodarone or perform urgent DC cardioversion if unstable.
- Definitive therapy: Catheter ablation of the accessory pathway if recurrent or high-risk.
📊 LGL vs WPW
| Feature | LGL Syndrome | WPW Syndrome |
| PR Interval | Short (<120 ms) | Short (<120 ms) |
| QRS Complex | Normal/narrow | Wide due to delta wave |
| Delta Wave | ❌ Absent | ✅ Present |
| Accessory Pathway | James fiber (atrial → His bundle) | Bundle of Kent (atrial → ventricle) |
| Clinical Risk | Mostly benign, rare VF risk | Higher risk of sudden cardiac death with pre-excited AF |
📚 References
