PET imaging may predict atrial fibrillation in patients based on F-18 FDG radiotracer uptake in the atrial walls, according to a study published January 20 in JACC: Advances.
The finding is from an analysis of 207 patients who underwent initial F-18 FDG-PET imaging at the University of Washington in Seattle and who were followed for more than three years, noted lead author Romanos Haykal, MD, and colleagues.
“Our study demonstrates that atrial uptake detected by PET imaging is associated with [atrial fibrillation], highlighting the potential role of PET imaging in [atrial fibrillation] risk prediction,” the group wrote.
Atrial fibrillation (AFib) is an irregular and often very rapid heart rhythm, and the condition increases the risk of stroke, heart failure, and other heart-related complications, the authors explained. Recent studies suggest that a metabolic shift in the heart in the use of glucose could play a role in sustaining the condition and promoting its progression, they added. Given its ability to visualize abnormal glucose metabolism, in this study, the group hypothesized that F-18 FDG-PET can provide a window into this cardiac metabolism.
Overall, the researchers included 207 patients who underwent FDG-PET imaging between 2017 and 2024, most often to screen for cardiac sarcoidosis. They visually assessed the images based on the intensity of F-18 FDG uptake, as well as performed a semiquantitative analysis using maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean) in the areas of highest uptake.
According to the results, 50 patients (24.2%) developed AFib over a median follow-up of 3.35 years. Compared with patients without incident AFib, patients who experienced it had higher age, prevalence of hypertension, coronary artery disease, and cardiac sarcoidosis, the researchers reported.
Representative axial and coronal F-18 FDG-PET/CT images demonstrate atrial metabolic activity. Kaplan-Meier analysis shows significantly higher cumulative incidence of AF in patients with atrial FDG avidity, the qualitative assessment of atrial FDG uptake, compared with those without avidity over the follow-up period (log-rank, p < 0.0001).JACC: AdvancesIn these patients, F-18 FDG uptake was more frequent in the atria (38% vs. 10.1%, p < 0.001) and ventricles (48% vs. 33.1%, p = 0.01) compared with those without AFib. Uptake was predominantly in the right (11.7%) compared with the left atrium (3.4%) or biatrial (1.9%). Finally, a Cox analysis showed atrial uptake to be a predictor of AFib (hazard ratio: 3.6; p < 0.001), according to the findings.
“This study highlights two important observations: atrial F-18 FDG uptake was associated with a high rate of incident [AFib], and a predominance of a right atrial uptake pattern,” the group wrote.
The study is consistent with one earlier study that also found higher activity in the right atrium, which may mean that the right atrium is involved earlier in the condition, the researchers suggested. Another possibility is that the left atrium in patients had higher fibrosis (scarring), which reduced metabolic activity and thereby yielded an apparent right atrial dominance, they added.
“Further histological studies are needed to uncover [this] significance,” the group concluded.
The full study is available here.