Advanced Heart Block and Asystole After Regadenoson Infusion: When Cautionary Tales Become Reality

Regadenoson (brand name Lexiscan) is a specific adenosine receptor agonist commonly used in pharmacologic stress testing due to its coronary vasodilatory effects. Despite it being generally well-tolerated, the American Society of Nuclear Cardiology established absolute and relative contraindications to the use of regadenoson in patients with certain co-morbidities such as uncontrolled hyper/hypotension, sinus node disease, and second-degree heart blocks. While cases of advanced heart block after the administration of regadenoson have been reported, they remain incidental. We report the case of an 84-year-old male sustaining second-degree type II heart block, followed by pulseless electrical activity and asystole after the administration of regadenoson.