Altered global myocardial substrate preference at rest and during pacing in coronary artery disease with stable...

In 21 control subjects with atypical chest pains and normal coronary arteries and in 64 patients with stable angina and coronary artery disease (CAD), myocardial exchanges of free fatty acids, glucose, lactate, citrate, glutamate, alanine and oxygen were determined before, during and after pacing. At rest, myocardial uptake of fatty acids was 50% lower in CAD patients than in the control subjects (p less than 0.001), whereas uptakes of glucose and lactate were twice as high (p less than 0.01). CAD patients showed increased myocardial glutamate uptake (p less than 0.001) and alanine release (p less than 0.001). In control subjects, myocardial fatty acid uptake was directly related (r = 0.54, p less than 0.01), whereas uptakes of glucose (r = -0.42, p less than 0.05) and lactate (r = -0.46, p less than 0.05) were inversely related to arterial fatty acid levels. Citrate release was inversely related to glucose uptake (R = 0.44, p less than 0.05). These relations were absent in CAD patients. Glutamate consumption correlated only with glucose uptake in CAD patients (p less than 0.001) but did so with lactate uptake and alanine release in all individuals (p less than 0.001). Pacing caused angina in the CAD patients but not in the control subjects. Pacing induced no metabolic changes among control subjects but provoked myocardial lactate release in 40 CAD patients, including an additional decrease of fatty acid uptake (p less than 0.05) and increase of glucose uptake (p less than 0.05) compared with resting levels.(ABSTRACT TRUNCATED AT 250 WORDS)