Key Points
- To identify the electrophysiological mechanisms underlying accelerated atrioventricular conduction in patients with Lown-Ganong-Levine syndrome.
- Obtained His bundle electrograms during sinus rhythm in three patients (N=3) presenting with recurrent supraventricular tachycardias, short P-R intervals, and normal QRS duration.
- Conducted atrial pacing in two patients to assess atrioventricular nodal and infranodal conduction responses.
- Sinus rhythm recordings showed normal A-H intervals in one patient, low-normal A-H intervals in two patients, and shortened H-V intervals in all three patients.
- Atrial pacing provoked attenuated A-H interval prolongation without altering conduction distal to the proximal His bundle.
- Electrophysiological findings indicate conduction acceleration via partial A-V nodal bypass tracts or functional bypass fibers, as well as accelerated conduction distal to the A-V node.
Structured PICO
PPopulation3 patients with histories of recurrent supraventricular tachycardias and electrocardiograms demonstrating a short P-R interval with a normal QRS (the Lown-Ganong-Levine syndrome)
IInterventionHis bundle recordings and atrial pacing
OOutcomeA-H (atrium-to-His bundle) time and H-V (His bundle-to-ventricle) timesurrogate
In patients with Lown-Ganong-Levine syndrome, His bundle recordings suggest accelerated conduction mechanisms such as partial A-V nodal bypass or accelerated distal conduction.