Myocardial citrate metabolism in control subjects and patients with coronary artery disease

Abstract

A significant release of citrate across the myocardium was demonstrated in twenty-two patients with coronary artery disease (CAD) and in ten control subjects in fasting resting state. In both groups, increasingly negative arterio-coronary sinus (A-Cs) plasma citrate differences correlated positively to arterial plasma free fatty acid (FFA)concentrations and negatively to (A-Cs) differences of plasma glucose. This supports the hypothesis that a citrate inhibition of glycoly-sis at the site of phosphofructokinase is of regulatory importance for myocardial glucose metabolism, and suggests that FFA supress glucose utilization by the heart in many by this mechanism. The capacity of plasma FFA to increase myocardial citrate release was signficantly higher in controls than in patients with CAD, and was found to be positively related to myocardial capacity of oxygen consumption as estimated from the product of heart rate and systolic blood pressure during an exercise tolerance test.

Key Words:

• arterio-coronary sinus concentration difference
• citrate
• free fatty acids
• glucose
• lactate
• maximal rate-pressure product