His-bundle parasystole masquerading as exercise-induced 2:1 atrioventricular block.
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.
Kasaoka
Y
Y
Department of Cardiovascular Medicine, Graduate School of Medicine, University of Tokyo, Japan. kasaokay-int@h.u-tokyo.ac.jp
Ajiki
K
K
Hayami
N
N
Murakawa
Y
Y
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*