title: Supernormal conduction in the anomalous bundles of the Wolff-Parkinson-White syndrome: an overlooked electrophysiologic property with potential clinical implications.
abstract: The anterograde refractory period (RP) of the accessory pathway (AP) is the main determinant factor of ventricular rate during atrial fibrillation in the Wolff-Parkinson-White (WPW) syndrome. We describe 3 examples of anterograde supernormal conduction (SNC) and 1 of retrograde SNC in APs. The paradoxical early recovery of propagation due to SNC, well inside a prolonged anterograde RP in the AP, may play a relevant role to determine the rate of ventricular response during atrial fibrillation, eventually leading to extremely fast ventricular rates, syncope, and even ventricular fibrillation in patients with WPW syndrome supposed a priori to be exposed to a low risk of sudden cardiac death. This may require very precise conditions, including an enhanced adrenergic influence on the heart. Retrograde SNC in APs may also participate in the mechanism of paroxysmal supraventricular tachycardias that are not easily induced by programmed cardiac stimulation.
authors: Cátedra de Cardiología, Facultad de Medicina, Pontificia Universidad Católica Argentina. pablochiale@fibertel.com.ar
authors: Pablo A
authors: PA
authors: Chiale
authors: Ernesto
authors: E
authors: Albino
authors: Hugo A
authors: HA
authors: Garro
authors: Horacio
authors: H
authors: Selva
authors: Raúl J
authors: RJ
authors: Levi
authors: Rubén A
authors: RA
authors: Sánchez
authors: Marcelo V
authors: MV
authors: Elizari
authors: Carlos B
authors: CB
authors: Alvarez
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000209:etiology / Q000503:physiopathology*; D004594:Electrophysiology; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013575:Syncope / Q000209:etiology; D014693:Ventricular Fibrillation / Q000209:etiology; D014927:Wolff-Parkinson-White Syndrome / Q000150:complications* / Q000503:physiopathology