Published Online
on September 17, 2009

A more recent version of this article appeared on November 1, 2009

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Original Article

In Vivo Assessment of Myocardial Glucose Uptake by Positron-Emission Tomography in Adults with the PRKAG2 Cardiac Syndrome

Andrew C.T. Ha¹; Jennifer M. Renaud¹; Robert A. deKemp¹; Stephanie Thorn¹; Jean DaSilva²; Linda Garrard¹; Keiichiro Yoshinaga¹; Arun Abraham¹; Martin S. Green¹; Rob S.B. Beanlands² and Michael H. Gollob^2,3

¹ University of Ottawa Heart Institute, Ottawa, Ontario, Canada;
² University of Ottawa Heart Institute & University of Ottawa, Ottawa, Ontario, Canada

^* Corresponding author; email: mgollob{at}ottawaheart.ca

Background—The PRKAG2 cardiac syndrome is an inherited metabolic disease of the heart characterized by excessive myocardial glycogen deposition. The biochemical alterations associated with this condition remain controversial and have not previously been studied in affected humans.

Methods and Results—PET imaging was used to quantitatively assess myocardial glucose uptake (MGU) in 6 adult subjects with the PRKAG2 cardiac syndrome and 6 healthy, matched controls using the glucose analogue ¹⁸F-FDG. Studies were performed under a euglycemic hyperinsulinemic clamp to ensure stable blood glucose levels. Rubidium-82 perfusion scans were performed to ensure myocardial differences in MGU were not the result of significant myocardial scar. In adult patients with phenotypic expression of disease, the median MGU of the left ventricle was 0.18 µmol/min/g (interquartile range: 0.14, 0.24) compared to 0.40 µmol/min/g (interquartile range: 0.30, 0.45) in the control group (p = 0.01). The median blood glucose during FDG-PET imaging was 4.72 mmol/L (interquartile range: 4.32, 4.97) in the PRKAG2 group and 4.38 mmol/L (interquartile range: 3.90, 4.79) in the control group (p = NS). The significant decrease observed in MGU in affected patients occurred in the absence of significant myocardial scar.

Conclusions—The PRKAG2 cardiac syndrome is associated with a reduction of glucose uptake in adult patients affected with this genetic condition. In this pilot study, ¹⁸F-FDG PET imaging is a useful tool to assess alterations in myocardial glucose transport in this inherited metabolic disease and provide insight into the biochemical pathophysiology of the diseased state.

Key Words: cardiomyopathy • genetics • tomography • PRKAG2 • Positron Emission Tomography