Creatine depletion and altered fatty acid metabolism in diseased human hearts: clinical investigation using ¹ h magnetic resonance spectroscopy and ¹²³ I BMIPP myocardial scintigraphy

BACKGROUND: In the heart, the creatine kinase system plays an important role in energy reserves, and myocardial energy production essentially depends upon fatty acid metabolism. PURPOSE: To examine myocardial creatine (CR) concentration and altered cardiac fatty acid metabolism in various forms of heart disease. MATERIAL AND METHODS: Myocardial CR concentration of the septum was measured by gated 1H magnetic resonance spectroscopy (MRS), applying a point-resolved spectroscopy (PRESS) sequence in 34 patients with heart disease. Of these patients, 14 underwent 123I BMIPP (radioactive fatty acid analogue) myocardial scintigraphy to evaluate myocardial fatty acid metabolism. Cardiac 123I BMIPP uptake was calculated as the heart-to-mediastinum count ratio. RESULTS: Myocardial CR concentration correlated positively with the left ventricular ejection fraction (LVEF) by echocardiography (R = 0.61, P<0.001, n = 34), suggesting that the degree of reduced CR is related to the severity of contractile dysfunction. Cardiac 123I BMIPP uptake also correlated positively with LVEF (initial image, R = 0.60, P<0.05; delayed image, R = 0.63, P<0.05; n = 14). There was a significant correlation between myocardial CR and cardiac 123I BMIPP uptake (initial image, R = 0.77, P<0.01; delayed image, R = 0.82, P<0.001; n = 14). CONCLUSION: Our study suggests an association between CR depletion and impaired fatty acid metabolism in various forms of heart diseases.