METABOLIC MISMATCH OF SEPTAL BETA-OXIDATION AND GLUCOSE-UTILIZATION IN LEFT-BUNDLE-BRANCH BLOCK ASSESSED WITH PET

Preserved septal uptake of the new long-chain fatty acid analog [F-18] FTHA was found in a patient with three-vessel disease, a history of pr evious anterior myocardial infarction and left bundle branch block (LB BB), despite severely decreased septal [F-18]FDG uptake that suggested scarred tissue. Nearly absent [F-19]FDG uptake in the septum could no t be explained by concordant reduction of septal perfusion as assessed by Tc-99m-MIBI SPECT. These data may point to divergent metabolic eff ects of the conduction abnormality in LBBB with consecutively reduced septal exogenous glucose utilization but unaffected septal beta-oxidat ion.