Clinical significance of fat infiltration in the moderator band and right ventricular myocardium in multislice CT, and its association with abnormal conduction seen in electrocardiogram

Abstract

PurposeWe evaluated the clinical significance of fat infiltration in the moderator-band (MB) of the right ventricle (RV) and in the RV myocardium (RVM) and its association with conduction abnormalities in the electrocardiogram. Materials and methods132 subjects (58 male; age 59±27years) with no findings of organic-disease (all right and left side hearts were normal) undergoing electrocardiogram-gated non-contrast multislice-CT (Light-Speed-Ultra-16) were retrospectively analyzed for the presence of fat infiltrating the MB or RVM. ResultsMB fat infiltration was detected in 42 subjects, but these individuals showed no significant differences in the incidence of right bundle branch-block, mean QRS-width or standard-deviation of the QRS-axis, which would have suggested the presence of hemi left bundle branch-block. Only age (64.3 vs 57.9years, p=0.025) was significantly different in subjects with MB fat infiltration. But logistic regression showed none of the factor associated with increased presence of MB fat infiltration. RVM fat infiltration was detected in 35 subjects, again with no significant differences in the incidence of right bundle branch-block, QRS width or standard-deviation of the QRS axis. Only age (65.9 vs 57.8years, p=0.001) and gender (71% vs 51% female, p=0.033) were significantly different in subjects with RVM fat infiltration. Logistic regression showed age (Odd-ratio=1.05 and 95% CI=1.01–1.08 p=0.008) and female sex (Odd-ratio=2.44 and 95% CI=1.03–5.88; p=0.043) were associated with increased RV fat infiltration. ConclusionsMB or RVM fat infiltration seen on CT may not indicate organized abnormal myocardial conduction, but RVM fat infiltration may indicate only degeneration due to aging, especially in females.