Left atrial epicardial adipose tissue radiodensity is associated with electrophysiological properties of atrial myocardium in patients with atrial fibrillation.

OBJECTIVE

To evaluate whether the epicardial adipose tissue (EAT) phenotype is associated with the electrophysiological properties of adjacent atrial myocardium in patients with atrial fibrillation (AF).

METHODS

Between January and May 2017, 30 consecutive patients referred for a first AF catheter ablation were prospectively included. For each patient, a pre-procedural computed tomography scan was performed to assess total and left atrial (LA) EAT amount and radiodensity. A detailed point-by-point voltage mapping using an electroanatomic mapping system was realized to assess the presence of LA low-voltage zone (LVZ).

RESULTS

Ten patients (33.3%) presented at least one LVZ. Older age (65 ± 7 vs. 58 ± 10 years, p = 0.05) was the only clinical parameter associated with LVZ. Despite no greater LA-EAT thickness by CT scan (3.0 [2.6-3.5] mm vs. 2.8 [2.2-3.1] mm, p = 0.354), patients with LA-LVZ presented significantly lower LA-EAT radiodensity than patients with no LA-LVZ (- 101.8 ± 12.5 HU vs. - 90.4 ± 6.3 HU, p = 0.004). No difference between total-EAT volume (131 ± 61 cm3 vs.107 ± 58 cm3, p = 0.361) and total-EAT radiodensity (- 106.8 ± 4.3 HU vs. - 102.4 ± 6.9 HU, p = 0.119) was found.

CONCLUSION

Low LA-EAT radiodensity is associated with the presence of LVZ in patients with medical history of AF.

KEY POINTS: • Cardiovascular risk factors are associated with low adipose tissue computed tomography attenuation. • Epicardial adipose tissue (EAT) has emerged as an important factor in the pathogenesis of metabolic-related cardiac diseases such as atrial fibrillation. • We showed that low left atrial EAT attenuation is associated with the presence of low-voltage zone, a surrogate for atrial fibrosis, within the adjacent myocardium.