Abstract
Abstract Introduction Myocardial perfusion imaging using positron emission tomography (PET) with 82Rubidium (82Rb) is used as a standard clinical examination. 82Rb-PET provides important information for the correct diagnosis and aids in prognostic risk assessment in patients with ischemic heart disease. 82Rb enters the myocardial cells by active transport of the sodium/potassium adenosine triphosphate transporter. Some antiarrhythmic drugs inhibits sodium/potassium adenosine triphosphate transporter. Purpose To determent if the uptake of 82Rb-PET using standard uptake value (SUV) is affected by administration of antiarrhythmic drugs. Methods Twenty-one Sprague-Dawley rats were baseline PET/CT scanned with 82Rb, using a Siemens preclinical PET/CT Inveon MM system and a Cardiogen-82 Rb generator. After baseline scan, the rats were divided into three groups. One control group without any treatment, and two received treatment with either orally administered Metoprolol 50mg/kg/24h or orally administered Amiodarone 120mg/kg/24h for seven days. All three groups were again PET/CT scanned with 82Rb-PET after the last administration on day seven. Data are presented as mean ±SEM. Results In the control group, there was no difference in mean SUV in the heart from day one to day seven (SUVmean 3.47±0.11 vs 3.45±0.35 p=0.97). In the group treated with metoprolol, likewise there was no difference in mean SUV in the heart from day one to day seven (SUVmean 3.87±0.13 vs 4.4±0.21 p=0.096). In contrast, in the group treated with amiodarone there was a significant difference in mean SUV from day one to day seven (SUVmean 4.14±0.15 vs 3.38±0.18 p=0.001). In all three groups there was no difference in mean SUV from day one to day seven in the liver and kidney. Conclusions The antiarrhythmic drug amiodarone had a clear impact on SUVmean in the heart. To the best of our knowledge, this is the first time it has been shown, that amiodarone lowers the SUV in 82Rb-PET in the heart. Amiodarone therefore seems to change to uptake of 82Rb in the myocyte. This could potentially influence the calculation to estimate absolute flow through the coronary arteries and lead to wrong conclusions regarding myocardial perfusion in patients treated with amiodarone. Further studies are needed to characterize the mechanism and to confirm the effect clinically.
Published Version
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