Transient AV Complete Heart Block: A Rare Complication Following Regadenoson Injection | Biomedgrid

Regadenoson is an A2A adenosine receptor agonist designed to selectively and transiently produce coronary vasodilation. Although regadenoson is a relatively selective A2A receptor agonist, it also has some weak action on the A1 receptor (10-fold lower affinity) which can produce atrioventricular block and bradycardia [1]. Regadenoson was approved by the FDA in 2008 for use as a pharmacologic stress agent during radionuclide myocardial perfusion imaging [2]. Well-documented contraindications for regadenoson use are second- or third-degree AV block or sinus node dysfunction without a functioning pacemaker (ASNC guideline reference). As of June 2017, a total of 56 cases of third-degree heart block and 26 cases of sinus arrest associated with regadenoson stress testing were reported via FAERS [3]. The incidence of overall high-grade AV block defined as second and third-degree AV block related to the administration of regadenoson at the dose given during MPI was low (less than 0.5%) and observed much less frequent compared to adenosine [4]. We report a case of 49-year-old woman who was referred to our stress laboratory for nuclear stress imaging with regadenoson and developed atrioventricular complete heart block (AVCHB) after regadenosone injection.