IMPAIRMENT OF BMIPP UPTAKE PRECEDES ABNORMALITIES IN OXYGEN AND GLUCOSE-METABOLISM IN HYPERTROPHIC CARDIOMYOPATHY

Impairment of fatty acid uptake is shown to precede myocardial perfusi on abnormality using I-123-labeled 15-(p-iodophenyl)-3-(R,S)-methylpen tadecanoic acid (BMIPP) in an experimental model of hypertrophic cardi omyopathy (HCM) and in human studies, We have recently demonstrated th at abnormalities of both glucose and oxidative metabolism precede the reduction of blood flow in HCM, The main purposes of this study were t o assess the frequency of abnormal findings in FDG uptake, BMIPP uptak e and oxygen metabolism and to clarify the relationship among these me tabolic parameters by using PET and SPECT. Methods: Twenty-eight subje cts with HCM underwent FDG- and acetate-PET and thallium- and BMIPP-SP ECT studies at rest, respectively. After correcting for partial volume effect, real percentages of FDG and BMIPP uptake were calculated. In addition, the clearance rate constant (K mono) of acetate was measured and normalized (%) to estimate the oxygen metabolism, Results: There were various metabolic abnormalities observed in patients with HCM, BM IPP uptake was often impaired without significant reduction of K mono values or FDG uptake, Thus, abnormality of BMIPP uptake was more frequ ently observed than that for FDG uptake or K mono values (p < 0.0001, respectively). FDG uptake was relatively maintained even in the segmen ts with reduced K mono values and reduced BMIPP uptake. Conclusion: HC M shows a variety of metabolic patterns; however, the results of our s tudy suggest that reduction of BM IPP uptake appears to be the most se nsitive indicator of metabolic abnormalities followed by reduction of oxidative metabolism in patients with HCM.