Background: Assessing for coronary artery disease (CAD) in patients with left bundle branch block (LBBB) is difficult with noninvasive cardiac imaging. Few studies report the prevalence of LBBB associated septal-apical perfusion defects using regadenoson stress on Positron Electron Tomography (PET) imaging.
Methods and results: We identified 101 consecutive patients with baseline LBBB, and without known CAD, who underwent rest-stress regadenoson PET. Investigators have the ability to prospectively identify studies, whose quality is limited by LBBB artifact. With the infusion of regadenoson, resting to peak stress heart rate rose from a median of 78 to 93 BPM. Despite this, LBBB perfusion artifacts were not identified in any studies. 10 individuals had both regadenoson SPECT and PET within 1 year. 3 of the 10 SPECT studies had LBBB artifacts, all of which were not seen on subsequent PET. 21 patients with PET had subsequent coronary angiography. Of these, 9 PETs were without significant inducible ischemia, and angiogram was without flow-limiting disease. 3 PETs identified inducible ischemia, but did not have flow-limiting disease on angiogram. 9 PETs identified inducible ischemia and had flow-limiting disease on angiogram.
Conclusions: In patients with LBBB undergoing regadenoson PET stress imaging, artifactual septal perfusion defects are rare.
Keywords: Left bundle branch block; coronary artery disease; positron emission tomography; regadenoson.