Myocardial turnover of plasma free @entity1718 during XXXX induced by atrial pacing.

@entity662 @entity1 @entity844 @entity1009 @entity26 @entity653 @entity951 @entity880 @entity1562 @entity299 @entity1718 @entity413 @entity2388
Myocardial extraction of free @entity1718 (FFA), together with @entity413 , @entity880 , @entity2388 , @entity653 and @entity26 was determined by simultaneous sampling of blood from an artery (a) and the coronary sinus (cs) at rest and during @entity662 induced by atrial pacing in seven fasting male @entity1 with @entity299 . Results were compared to those, at rest and during pacing at heart rate 140 beats @entity1009 , in ten healthy @entity1 of similar age. A continuous i.v. infusion of 14C oleate and 3H palmitate enabled the calculation of simultaneous myocardial uptake and release of FFA as well as of the fraction of extracted FFA which underwent direct oxidation. During @entity662 lactate net extraction decreased to become, in some @entity1 , negative. FFA extraction, as estimated from the fractional extraction of labelled @entity844 was likewise decreased, while the a-cs O2 difference was not significantly altered. The fractional oxidation of extracted FFA was increased, whereas the calculated @entity844 release from the heart was unaltered. The increase in fractional oxidation was quantitatively correlated with the decrease in lactate extraction suggesting that it was related to the degree or extent of ischaemia. It was also proportional to the decrease in FFA extraction. Thus, in @entity1 with @entity951 the @entity1562 may be subjected to a limitation not only with regard to @entity26 but also substrate flux into the myocardial cells.
