Long-chain triglycerides improve recovery from myocardial stunning in conscious dogs

Objectives: Free fatty acid (FFA) oxidation is depressed in the postischaemic stunned myocardium and recovers in parallel with the normalization of contractile performance. Assuming a causal role for this metabolic disturbance in the pathogenesis of stunning, questioned whether exogenous administration of high dose triglycerides during reperfusion of postischaemic myocardium, could improve its functional recovery. Methods: Thirteen dogs were chronically instrumented to measure global and regional haemodynamics and to produce a 10 min episode of regional myocardial ischaemia. In 7 dogs, Intralipid(R) 20% was administered i.v. during the reperfusion phase. Contractile recovery of stunned myocardium was compared with control saline treatments. The series were repeated in another 6 animals, but oxfenicine (CPT I inhibitor) preceeded Intralipid(R) during reperfusion. Results: Contractile recovery of stunned myocardium was faster and more extensive when Intralipid(R) was administered during reperfusion than with saline treatment (wall thickening fraction 86+/-6% of preischaemic controls versus 52+/-11% at 90 min post-reperfusion; P <0.05). Oxfenicine pretreatment completely abolished this beneficial effect. Conclusions: Exogenous administration of triglycerides during reperfusion of postischaemic myocardium improves functional recovery from stunning. This beneficial effect most likely operates through enhanced FFA availability and/or oxidation since it could be abolished by selective inhibition of the carnitine palmitoyl transferase I enzyme.