title: His-bundle parasystole masquerading as exercise-induced 2:1 atrioventricular block.
abstract: We describe a case of symptomatic pseudo-AV block due to His-bundle parasystole masquerading as exercise-induced 2:1 AV block. Electrophysiologic study revealed the presence of His-bundle parasystole, and the fluctuation of parasystolic cycle length could be explained by the concept of modulated parasystole. Modulated parasystole is a possible explanation for maintenance of stable 2:1 AV conduction at an atrial rate of specific range during exercise.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, University of Tokyo, Japan. kasaokay-int@h.u-tokyo.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Kasaoka
authors.forename: K
authors.initials: K
authors.lastname: Ajiki
authors.forename: N
authors.initials: N
authors.lastname: Hayami
authors.forename: Y
authors.initials: Y
authors.lastname: Murakawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002036:Bundle of His / Q000503:physiopathology*; D003937:Diagnosis, Differential; D022062:Electrophysiologic Techniques, Cardiac; D015444:Exercise / Q000502:physiology*; D006325:Heart Atria / Q000503:physiopathology*; D006327:Heart Block / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D008297:Male; D017574:Parasystole / Q000175:diagnosis* / Q000209:etiology*