title: Paradoxical undersensing during atrial flutter: what is the mechanism?
abstract: A patient with congenital complete heart block underwent implantation of a dual-chamber pacemaker. He presented to the emergency room with fatigue and was found to be in atrial flutter. Device interrogation revealed undersensing of 5 mV flutter waves at a programmed sensitivity of 0.5 mV. Due to undersensing, mode switch did not occur. This case illustrates apparently paradoxical undersensing of atrial flutter waves by a dual-chamber pacemaker and can be explained by a phenomenon known as "quiet timer blanking."
authors.affiliation: From the Virginia Commonwealth University Medical Center, Richmond, VA 23298-0053, USA.
authors.forename: Gautham
authors.initials: G
authors.lastname: Kalahasty
authors.forename: David N
authors.initials: DN
authors.lastname: Kenigsberg
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wood
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Ellenbogen
mesh_terms: D000328:Adult; D001282:Atrial Flutter / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy; D004868:Equipment Failure; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial / Q000592:standards*