Left ventricular metabolism, function, and sympathetic innervation in men and women with type 1 diabetes.

ABSTRACT

BACKGROUND: In type I diabetes (T1DM), alterations in LV function may occur due to changes in innervation, metabolism, and efficiency. OBJECTIVES: We evaluated the association between sympathetic nerve function, oxidative metabolism, resting blood flow, LV efficiency and function in healthy diabetics, and assessed gender differences. METHODS: Cross-sectional study of 45 subjects with T1DM, 60% females, age 34 ± 13 years, and 10 age-matched controls. Positron emission tomography (PET) imaging with [(11)C]acetate and [(11)C]meta-hydroxyephedrine was performed, in addition to cardiac magnetic resonance imaging. RESULTS: There were no significant differences in LV function, innervation, or oxidative metabolism between T1DM and controls. Cardiac oxidative metabolism was positively associated with higher levels of sympathetic activation, particularly in women. Diabetic women had significantly lower efficiency compared with diabetic men. Resting flow was significantly higher in diabetic women compared with diabetic men, and tended to be higher in female controls as well. CONCLUSIONS: Measures of myocardial function, metabolism, blood flow, and sympathetic activation were preserved in young, otherwise healthy, T1DM patients. However, T1DM women presented with greater myocardial oxidative metabolism requirements than men. Ongoing studies are evaluating changes over time.