Creatine depletion and altered fatty acid metabolism in diseased human hearts:: Clinical investigation using 1H magnetic resonance spectroscopy and 123I 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 H-1 magnetic resonance spectroscopy (MRS), applying a point-resolved spectroscopy ( PRESS) sequence in 34 patients with heart disease. Of these patients, 14 underwent I-123 BMIPP ( radioactive fatty acid analogue) myocardial scintigraphy to evaluate myocardial fatty acid metabolism. Cardiac I-123 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 I-123 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 I-123 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.