Myocardial exchange of metabolites after nitroglycerin in patients with coronary artery disease.
We studied the effects of sublingual nitroglycerin (dose range 0.5-1.0 mg) on cardiac metabolism in the resting state in 12 patients with chronic coronary artery disease. Seven patients with chronic coronary artery disease served as a control group. No patient from either of the groups experienced angina pectoris during the study. Reduced heart work after nitroglycerin was evident from a 34% decrease of oxygen uptake (P less than 0.001) and a 35% fall in coronary sinus blood flow (P less than 0.01). Nitroglycerin decreased lactate extraction by 30% (P less than 0.05), lactate uptake by 58% (P less than 0.025); glucose uptake by 47% (P less than 0.01) while net exchange of free fatty acids did not change. The aorto-coronary sinus difference of plasma citrate became increasingly negative (from -4 +/- 3 mumol/l to -8 +/- 2 mumol/l) (P less than 0.02) after nitroglycerin. In the control group coronary sinus blood flow and myocardial exchange of oxygen and substrates remained unchanged. Our results suggest a relatively increased myocardial utilization of free fatty acids compared with that of carbohydrates after nitroglycerin. This may in part be explained as an inhibition of glycolysis due to citrate accumulation. The study indicates that myocardial lipid-carbohydrate metabolism is disturbed in chronic coronary artery disease even in patients without clinical evidence of ischaemia in resting state and that nitroglycerin reverses this condition towards the metabolism of the normal heart.
D001786:Blood Glucose / Q000378:metabolism; D002951:Citrates / Q000097:blood; D003327:Coronary Disease / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D009060:Mouth Floor; D009206:Myocardium / Q000378:metabolism*; D005996:Nitroglycerin / Q000494:pharmacology*; D010101:Oxygen Consumption; D012146:Rest
D001786:Blood Glucose; D002951:Citrates; D005230:Fatty Acids, Nonesterified; D007773:Lactates; D005996:Nitroglycerin