Is regadenoson an appropriate stressor for MPI in patients with left bundle branch block or pacemakers?
Gregory S Thomas1, Carissa R Kinser, Rita Kristy
1MemorialCare Heart & Vascular Institute, Long Beach Memorial Medical Center, 2801 Atlantic Avenue, Long Beach, CA, 90806, USA, gthomas1@memorialcare.org.
Background:
Patients with LBBB or ventricular pacemaker undergoing MPI are at risk for false positive MPI results in the setting of an elevated heart rate (HR) with exercise or dobutamine stress. The areas of increased apparent ischemia are typically the LAD and septal territories.
Methods:
In a subanalysis of the ADVANCE MPI 1 and 2 studies, perfusion on an initial adenosine and a second MPI study with regadenoson or adenosine was compared by visual and quantitative analysis. Among 2,015 patients, 64 had LBBB and 93 had pacemakers. The hemodynamic response during the second scan was compared in those with and without LBBB and PM.
Results:
Following regadenoson, peak HR in the LBBB group increased by a mean of 25.4 compared to 15.3 bpm following adenosine (P = .0083). In the pacemaker group HR was blunted, 11.8 and 8.1 following regadenoson and adenosine, respectively (P = .1262). However, the visually assessed summed difference score and the quantitatively assessed extent of ischemia for the LAD and septal territories and the entire LV did not differ between the initial adenosine and subsequent regadenoson scans.
Conclusions:
The significant increase in HR observed with regadenoson compared to adenosine did not translate into greater perfusion defects in the LAD or septal territories in patients undergoing regadenoson stress.
Insights
Regadenoson increased heart rate more than adenosine in patients with LBBB, but did not cause more perfusion defects on myocardial perfusion imaging (MPI). This suggests regadenoson is safe for these patients.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Diagnostic Imaging
Background:
- Patients with left bundle branch block (LBBB) or pacemakers may experience false positives during myocardial perfusion imaging (MPI) with elevated heart rates.
- Ischemia is often falsely localized to the left anterior descending (LAD) and septal territories.
Purpose of the Study:
- To compare the hemodynamic response and perfusion defects during regadenoson stress versus adenosine stress in patients with LBBB or pacemakers.
- To evaluate the safety and efficacy of regadenoson in this patient population.
Main Methods:
- A subanalysis of the ADVANCE MPI 1 and 2 studies included 2,015 patients, with 64 having LBBB and 93 having pacemakers.
- MPI was performed using adenosine, followed by a second scan with regadenoson or adenosine.
- Visual and quantitative analyses assessed perfusion, and hemodynamic responses were compared.
Main Results:
- Regadenoson significantly increased peak heart rate (HR) in the LBBB group compared to adenosine (25.4 vs. 15.3 bpm).
- The pacemaker group showed a blunted HR response with both agents.
- No significant differences in summed difference scores or extent of ischemia were found between adenosine and regadenoson scans.
Conclusions:
- Increased HR with regadenoson did not lead to more perfusion defects in the LAD or septal territories.
- Regadenoson appears to be a safe alternative to adenosine for stress MPI in patients with LBBB or pacemakers.
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