Is septal glucose metabolism altered in patients with left bundle branch block and ischemic cardiomyopathy?
Left bundle branch block (LBBB) is common in patients with heart failure (HF) and contributes to left ventricular (LV) dysfunction. The abnormal septal motion may alter septal metabolic demand but this has not been well characterized in patients with ischemic cardiomyopathy (ICM) and LV dysfunction. The aim of this study was to determine the effect of LBBB on septal metabolism in patients with ICM, LV dysfunction, and LBBB. METHODS: Fifty-three patients with LV dysfunction and ICM were identified: 34 with LBBB, 19 with normal QRS (=100, control patients). PET using (18)F-FDG and (82)Rb was used to measure myocardial glucose metabolism and perfusion, respectively. Perfusion-metabolism differences were determined. Scar scores (matched decreases in (18)F-FDG and (82)Rb), mismatch scores (hibernating myocardium with decreased (82)Rb relative to (18)F-FDG), and reverse-mismatch (R-MM) scores (reduced (18)F-FDG relative to (82)Rb) were assessed in the septum and lateral wall. RESULTS: (18)