Atrioventricular block precipitated by isoproterenol

Ann Noninvasive Electrocardiol. 2015 Jul;20(4):397-401. doi: 10.1111/anec.12192. Epub 2014 Sep 18.


An isoproterenol infusion was administered during an electrophysiologic study (EPS) in a patient with a history of near syncope, left bundle branch block, and no documented atrioventricular (AV) block. Isoproterenol precipitated classic 2:1 Infra-Hisian AV block most probably proximal to the site of recording a His-Purkinje potential consistent with right bundle branch activity. Paroxysmal AV block also occurred during isoproterenol washout at a different site located distal to the presumed right bundle branch potential. Isoproterenol may be valuable diagnostically in an occasional patient suspected of AV block in whom an EPS is unrevealing and a drug challenge is negative.

Keywords: atrioventricular block; electrophysiologic study; isoproterenol; paroxysmal atrioventricular block.

Publication types

  • Case Reports

MeSH terms

  • Adrenergic beta-Agonists / adverse effects*
  • Atrioventricular Block / chemically induced*
  • Atrioventricular Block / complications
  • Atrioventricular Block / physiopathology
  • Bundle of His / physiopathology
  • Bundle-Branch Block / complications
  • Bundle-Branch Block / physiopathology
  • Electrocardiography
  • Female
  • Humans
  • Isoproterenol / adverse effects*
  • Middle Aged


  • Adrenergic beta-Agonists
  • Isoproterenol