Regadenoson is a safe and well-tolerated pharmacological stress agent for myocardial perfusion imaging in post-heart transplant patients

The safety and tolerability of regadenoson (REG), a newer adenosine A(2a) receptor agonist, has not been tested in orthotopic heart transplant (OHT) patients. Retrospective review of a tertiary care center experience of OHT patients who underwent a REG single-photon emission computed tomography (SPECT) study as part of the work-up for cardiac allograft vasculopathy. The control group included those same patients who had prior adenosine-based SPECT. A total of 40 patients met the above criteria. Mean time from OHT to adenosine-SPECT and REG-SPECT was 8.2 +/- A 4.8 years vs 9.8 +/- A 4.5 years, respectively (P < .001). Both vasodilators had similar side effect profiles (P = .10), produced significant heart rate acceleration and asymptomatic hypotension (P < .001). There were no episodes of bradycardia and/or AV block with REG. Despite adjustment for medication status, adenosine was still associated with more conduction abnormalities (8 vs 1 event with REG, P = .02) including five episodes of 2nd degree AV block (Mobitz type II) and three episodes of sinus pause. This is the first reported use of REG in OHT patients. REG appears to be safe and well tolerated without significant cardiovascular adverse events.