Detection of aterations in left ventricular fatty acid metabolism in patients with acute myocardial infarction by 15-(p-¹²³I-phenyl)-pentadecanoic acid and tomographic imaging

15-(p-iodine 123-phenyl)-pentadecanoic acid (IPPA) is a synthetic radiolabeled fatty acid with kinetics similar to palmitate. Fourteen patients who had had an acute myocardial infarction 7 ± 6 days earlier and 9 normal volunteers were studied after being injected with IPPA. The volunteers were remarkable for homogeneous uptake and metabolism of IPPA; 13 of 14 infarct patients showed areas of decreased uptake >2 SDs below the mean of the voluntters. Metabolism was homogeneous in the volunteers (14.2% ± 5.8%) and was significantly higher than in regions identified as infarcted (3.9% ± 12.1%, p < 0.001). Noninfarcted regions in the patients demonstrated significantly increased rates of IPPA metabolim compared to rates in volunteers (23.0% ± 9.6% p < 0.001). We conclude that patients with recent myocardial infarction have abnormalities of fatty acid metabolism such as decreased uptake and clearance of fatty acid in regions of infarction and normal uptake but relatively increased acid clearance in unaffected regions of the myocardium.