Heart Rhythm O2 (Aug 2021)

Detection of fibrotic remodeling of epicardial adipose tissue in patients with atrial fibrillation: Imaging approach based on histological observation

  • Yumi Ishii, MD,
  • Ichitaro Abe, MD, PhD,
  • Shintaro Kira, MD, PhD,
  • Taisuke Harada, MD,
  • Masayuki Takano, MD,
  • Takahiro Oniki, MD, PhD,
  • Hidekazu Kondo, MD, PhD,
  • Yasushi Teshima, MD, PhD,
  • Kunio Yufu, MD, PhD,
  • Takashi Shuto, MD, PhD,
  • Tomoyuki Wada, MD, PhD,
  • Mikiko Nakagawa, MD, PhD,
  • Tatsuo Shimada, PhD,
  • Yoshiki Asayama, MD, PhD,
  • Shinji Miyamoto, MD, PhD,
  • Naohiko Takahashi, MD, PhD

Journal volume & issue
Vol. 2, no. 4
pp. 311 – 323

Abstract

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Background: Fibrotic remodeling of epicardial adipose tissue (EAT) is crucial for proinflammatory atrial myocardial fibrosis, which leads to atrial fibrillation (AF). Objectives: We tested the hypothesis that the ratio of central to marginal adipocyte diameter in EAT represents its fibrotic remodeling. Based on a similar concept, we also tested whether the percent (%) change in EAT fat attenuation determined using computed tomographic (CT) images can detect this remodeling. Methods: Left atrial appendages were obtained from 76 consecutive AF patients during cardiovascular surgery. EAT in the central area (central EAT: C-EAT) and that adjacent to the atrial myocardium (Marginal EAT: M-EAT) were evaluated histologically. CT images for all of the 76 patients were also analyzed. Results: The adipocyte diameter was smaller, fibrotic remodeling of EAT (EAT fibrosis) was more severe, and infiltration of macrophages and myofibroblasts was more extensive in M-EAT than in C-EAT. EAT fibrosis was positively correlated with adipocyte diameter in C-EAT and negatively correlated in M-EAT, resulting in a positive correlation between EAT fibrosis and the ratio of central to marginal adipocyte diameter (C/M diameter ratio; r = 0.73, P < .01). The C/M diameter ratio was greater in patients with persistent AF than in those with paroxysmal AF. CT images demonstrated that the %change in EAT fat attenuation was positively correlated with EAT fibrosis. Conclusion: Our results suggest that the central-to-marginal adipocyte diameter ratio is tightly associated with fibrotic remodeling of EAT. In addition, the %change in EAT fat attenuation determined using CT imaging can detect remodeling noninvasively.

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