what is LGL

  My son was diagnosed at birth with WPW, and has been treated with Atenolol for the past 3 years.  We are currently attempting to have an ablation done, but at one of the visits to his doctor he told us that it was more LGL now then WPW.  What is the difference?
  Thanks for your help

[CCF Cardio MD - MTR]

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Dear Chris, thank you for your question.  WPW (Wolff-Parkinson-White) syndrome is caused by an accessory electrical pathway between the atria and ventricles of the heart.  Normally, electrical activity can only pass between the atria and the ventricles through the AV node.  When an accessory pathway (AP) is present, the electrical conduction can bypass the AV node and spread to the ventricles by passing through the AP.  This phenomenon is called pre-excitation and is seen on the surface ECG as a delta wave in the QRS complex.  Supraventricular tachycardia (SVT) results with WPW when an reciprocating electrical circuit is established between the AP and the AV node; this is the common manifestation of WPW.  Medications like atenolol slow electrical conduction and can limit the episodes of SVT, but only radiofrequency ablation can eliminate the AP to cure the disorder.  LGL refers to the Lown-Ganong-Levine syndrome which may not even exist according to some cardiologists.  It is thought that LGL is caused by an AP that inserts just below the AV node in the Bundle of His fibers (atriohisian tract) to cause a tachycardia with a short PR interval and a normal QRS complex (unlike WPW with a delta wave).  However, there is no definitive proof that this syndrome does exist clinically.  Thus, I think you speak with your son's cardiologist about this issue and ask what the plans are for an ablation procedure.
I hope you find this information useful.  Information provided in the heart forum is for general purposes only.  Only your physician can provide specific diagnoses and therapies. Please feel free to write back with additional questions.
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