Effect of acute postinfusion lipemia and free fatty acids on myocardial contractility: Assessment with radionuclide ventriculography

Abstract

Equilibrium gated radionuclide ventriculography was used to evaluate the effect of intravenous fat-emulsion overload and excess of free fatty acids (FFA) on left ventricular ejection fraction (LVEF) in 20 patients with and without coronary artery disease (CAD). Fifteen of these patients had normal (>50%) baseline LVEF and 5 had low (<50%) baseline LVEF. From 100 to 150 ml of 20% artificial fat emulsion (Liposyn) was infused over 20–25 min. At the end of the infusion, triglyceridemia reached 820±220 mg% and left ventricular ejection fraction decreased from baseline 62±19% (mean±SD) to 58±16% (P<0.05, paired t-test). After completion of Liposyn infusion, 5,000 U of heparin was administered intravenously and monitoring of LVEF was continuod. One and one-half hours following heparin administration, plasma FFA levels reached 3.7+2.0 mmol/l and LVEF rose to 69±19% (P<0.001, paired t-test). Our data indicate that acute intravenous fat overload can suppress and high pathophysiologic levels of FFA can increase LVEF. This effect is more uniform and statistically more reliable in patients with normal LVEF. The study failed to demonstrate any significant difference in the effect of this pharmacologic intervention between patients with and without CAD.