Abstract 3946: Detrimental Effects of Acute Non-esterified Fatty Acids Deprivation on Cardiac Metabolism and Function in Patients With Heart Failure
Background and aims: This study was designed to evaluate the effects of acute changes in non-esterified fatty acids (NEFA) availability on LV energy homeostasis and function in patients with chronic heart failure.
Materials and methods: Cardiac function and the relative content of LV phosphocreatine (PCr) and ATP were assessed non-invasively using in vivo magnetic resonance imaging (MRI) and 31P MR-spectroscopy (MRS) in 10 individuals with chronic heart failure [age: 74±9 ys, BMI: 25.6±1.9 kg/m2, NYHA class: 2 (1–3), ejection fraction (EF): 35±7%, fasting glucose: 96±11 mg/dl; fasting insulin: 6.3±3.0 μU/ml] in two experimental conditions 7 days apart. In Study 1, MRI and 31P-MRS data were acquired before and 2 hours after the administration of an i.v. bolus + continuous heparin infusion designed to achieve a serum NEFA concentration of 1.2–1.5 mM. In Study 2, the same procedure was performed before and 2 hours after the oral administration of acipimox designed to achieve a serum NEFA concentration of 0.1– 0.2 mM. Acquisitions were obtained in the fasting and resting state.
Results: During the studies serum glucose and insulin concentration did not significantly change; serum NEFA increased from 0.65±0.24 to 1.21±0.47 mM during Study 1 and dropped from 0.68±0.25 to 0.15±0.06 mM during Study 2. The PCr/ATP ratio did not change during Study 1 (from 1.70±0.22 to 1.75±0.34; P=0.49) meanwhile during Study 2 it dropped from 1.81±0.23 to 1.53±0.32 (P=0.016) and the percent change was also different (102±12% vs. 85±15%; P=0.009). In parallel, LVEF did not change during Study 1 (from 35±13% to 34±13%; P=0.21) meanwhile it dropped from 36±12% to 33±11% (P=0.03) during Study 2.
Conclusion: In patients with chronic heart failure acute reduction of serum NEFA concentration impaired LV energy metabolism and function meanwhile a two-fold increment did not induce any detectable change. These data show that acute deprivation of fatty substrates may be detrimental for cardiac metabolism and function.