Chronic LBBB. -Had bronchospasm when submitted for MPS with dipyridamole, so she was switched to exercise.
Teaching points:
Regadenoson is a pharmacologic agent approved by the FDA in 2008 as an agent for use in stress testing and can also be used in combined protocols with exercise.
Regadenoson produces maximal hyperemia quickly after IV injection as a bolus and maintains it for an optimal duration, practical for myocardial perfusion imaging.
Regadenoson is an agonist with low affinity for the A2A adenosine receptor, and at least a 10-fold lower affinity for the A1 adenosine receptor. In addition, it has relatively weak affinity for the A2B and A3 adenosine receptors.
Coronary vasodilation and an increase in coronary blood flow (CBF) results from activation of the A2A adenosine receptor by regadenoson.