title: An unusual WPW syndrome: What is the preexcitation variant?
abstract: A 15-year-old female with WPW syndrome and normal heart underwent an electrophysiology study for paroxysmal palpitations and syncope. Intravenous adenosine produced an unexpected response of QRS changes and advanced AV block. During isoproteronol infusion, short-lasting and poorly tolerated wide QRS tachycardia was inducible, but pacing maneuvers were not feasible during tachycardia to determine its definitive mechanism. However, various electrophysiologic phenomena including adenosine response, junctional beats pattern, and multisite atrial pacing were helpful to overcome the diagnosis challenges. Finally, careful evaluation of tachycardia features and the comprehensive electrophysiology study were crucial to establish presence of unusual preexcitation variants, and thus to guide successful catheter ablation of the arrhythmic substrate.
authors.affiliation: Arrhythmia & Electrophysiology Unit II, Humanitas Gavazzeni Clinics, Bergamo, Italy.
authors.forename: Hussam
authors.initials: H
authors.lastname: Ali
authors.affiliation: Heart & Vascular Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates.
authors.forename: Antonio
authors.initials: A
authors.lastname: Sorgente
authors.affiliation: Arrhythmia & Electrophysiology Unit II, Humanitas Gavazzeni Clinics, Bergamo, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: De Ambroggi
authors.affiliation: Arrhythmia & Electrophysiology Research Center, Humanitas Clinical & Research Center, Rozzano, Milan, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Cappato
keywords: Catheter ablation; Mahaim; Preexcitation variant; WPW syndrome