NUCLEAR CARDIOLOGY Septal Perfusion and Wall Thickening in Patients with Left Bundle Branch Block Assessed by Technetium-99m-Sestamibi Gated Tomography

Septal hypoperfusion is often observed in patients with complete left bundle branch block (LBBB) in myocardial perfusion imaging. Abnormal wall motion in the septal region may potentially cause artifactual perfusion abnormalities. To assess the effect of abnormal wall thickening on myocardial perfusion images, ECG-gated sesta-mibi SPECT was performed on 12 patients with LBBB and 10 normal subjects used as controls. Methods: After administration of 740 MBq ""Tc-sestamibi injection at rest, ECG-gated SPECT was obtained 60 min later with division of the cardiac cycle into eight frames. Results: Septal hypoperfusion was noted in 10 patients on nongated images and 11 patients on end-systolic (ES) images, whereas only two patients showed abnormalities on end-diastolic (ED) images. The septal to lateral wall count ratio in the LBBB grou