Left atrium wall metabolism by PET-CT in patients with hypertrophic cardiomyopathy

Background In hypertrophic cardiomyopathy (HCM) diastolic dysfunction leads to left atrium (LA) enlargement and often to the occurrence of atrial fibrillation. The aim of this study was to assess myocardial LA wall metabolism with its volume (LAV) and with the presence of atrial fibrillation (AF) in patients with non-obstructive cardiomyopathy. Methods and Results Thirty patients were recruited with an age of 54.4±11.3, 60% males and a with a LAV of 46.1±16.5. LA metabolism was assessed by PET-CT performed in a Biograph Vision 600, Siemens and to suppress physiologic 2-[18F]FDG cardiac uptake, a 2 day high-fat/low-carbohydrate diet and a 12 hours overnight fast were prescribed. Metabolism in the LA through maximum 2-[18F]FDG uptake by drawing several regions of interest (ROI) in the left atria and the maximum found value was corrected to vascular activity in the right atria (TBR). A TBR above 1 was seen in 13.3% and AF was present in 23.3% of the patients. The TBR in the LA wall was of 0.84±0.15. LA TBR was correlated with LAV with a coefficient of 0.42(p=0.02). Although patients with atrial fibrillation exhibit higher values of TBR, no statistical significance was found (AF 0.92±0.18 / No AF 0.81±0.14 p=0.07). Conclusions Increased metabolism in the LA wall in patients with HCM is related with its volume and could be related with the presence of AF.