Interventricular conduction delay is associated with myocardial fatty acid metabolic abnormalities in dilated cardiomyopathy

Abstract

Background: Interventricular conduction delay (IVCD) is an important prognostic indicator in dilated cardiomyopathy (DCM). Abnormalities in glucose metabolism are related to prolonged QRS duration in patients with severe heart failure, and improvement after resynchronization therapy is also reported. However, an association between IVCD and abnormal myocardial fatty acid metabolism has not been well understood in DCM patients. Methods: To investigate the association of the metabolic abnormalities with IVCD, I-123 beta-methyliodophenylpentadecanoic acid (BMIPP) and thallium-201 (Tl) single photon emission computed tomography (SPECT) were performed in 62 non-ischemic DCM patients. The uptake was scored visually from 0 (normal) to 3 (defect) in 17 segments of the left ventricle (LV), and a total defect score in all 17 segments was calculated. Results: Seventeen patients with prolonged QRS duration (<130 msec) showed greater LV end-diastolic diameter (70±13 versus 64±7mm, p=0.007) and lowere LV ejection fraction (25 ± 10 versus 31 ± 10%, p = 0.04) as compared with the other 44 without IVCD. The total defect score of BMIPP was greater in the patients with IVCD (22 ± 6 versus 16 ± 8, p = 0.009), although that of Tl was similar. Multiple logistic regression analysis for 10 clinical variables including scintigraphic parameters demonstrated a strong association of the BMIPP score with IVCD (odds ratio: 1.19/ 1 increase, p = 0.02). Conclusions: IVCD in DCM patients is strongly associated with myocardial fatty acid metabolic abnormalities.