False-positive defects on exercise 99mTc-sestamibi SPECT imaging, but not on dipyridamole 99mTc-sestamibi SPECT imaging, in a patient with right bundle branch block (RBBB)

Abstract

False-positive findings with myocardial perfusion imaging (MPI)
have frequently been identified in the presence of left bundle
branch block (LBBB) and tend to lower the accuracy of MPI in
individuals with normal coronary angiographs. Pharmacologic
stress is recognized as the preferred method for MPI in patients
with LBBB. In contrast, very few studies have evaluated the effect
of right bundle branch block (RBBB) on MPI, and there is
no consensus regarding the selection of pharmacologic versus
exercise stress during MPI for the RBBB patient. In this study,
we present a 45-year-old man with RBBB, who has a normal coronary artery angiography, but who showed abnormal myocardial
perfusion with exercise MPI, and normal perfusion on
dipyridamole MPI. The aim of the study is to stimulate awareness
that the stress method selected for patients with RBBB can
potentially interfere with the accuracy of the data.