title: A narrow QRS tachycardia and cannon A waves: What is the mechanism?
abstract: Regular narrow QRS tachycardia, particularly if well-tolerated, is usually considered a "benign" arrhythmia of a supraventricular origin. This case concerns an 82-year-old male with ischemic heart disease who presented with recurrent episodes of a narrow QRS tachycardia that was initially diagnosed and treated as atrial tachyarrhythmia. However, careful physical examination and ECG analysis established the correct diagnosis, and the patient was managed appropriately. Remarkably, the observation of irregular cannon A waves, and Lewis lead recording, confirmed atrioventricular dissociation during tachycardia and indicated its underlying mechanism.
authors.affiliation: Arrhythmia & Electrophysiology Unit II, Humanitas Gavazzeni Clinics, Bergamo, Italy.
authors.forename: Hussam
authors.initials: H
authors.lastname: Ali
authors.affiliation: Arrhythmia & Electrophysiology Unit II, Humanitas Gavazzeni Clinics, Bergamo, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Epicoco
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 Unit II, Humanitas Gavazzeni Clinics, Bergamo, Italy.
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Lupo
authors.affiliation: Arrhythmia & Electrophysiology Unit II, Humanitas Gavazzeni Clinics, Bergamo, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Foresti
authors.affiliation: Arrhythmia & Electrophysiology Research Center, Humanitas Clinical & Research Center, Rozzano, Milan, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Cappato
mesh_terms: D000369:Aged, 80 and over; D002921:Cicatrix / Q000150:complications / Q000175:diagnosis; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000379:methods*; D006327:Heart Block / Q000150:complications* / Q000175:diagnosis*; D006801:Humans; D008297:Male; D017180:Tachycardia, Ventricular / Q000150:complications* / Q000175:diagnosis*
keywords: Lewis lead; atrioventricular dissociation; cannon A waves; ventricular tachycardia