Intensity and Distribution of Patchy Late Gadolinium Enhancement in Left Atrium in Patients With Atrial Fibrillation.

Purpose: Late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (MRI) studies were performed on healthy individuals to establish signal intensity thresholds for reproducible left atrial (LA) patchy LGE detection. Using established criteria, differences in LA patchy LGE between healthy volunteers (HV) and patients with atrial fibrillation (AF) or hypertension were analyzed.

Methods: Fifty-three patents with AF (mean age 56 years, 60% men), 25 patients with hypertension and no history of AF (mean age 54 years, 40% men), and 28 HV (mean age 50 years, 52% men) were enrolled in an observational, non-interventional, case-control prospective study. LA patchy LGE quantification was performed using LGE MRI (1.5 T scanner, voxel size 1.25x1.25x2.5 mm) and the custom-built software based on estimation of LA voxel image intensity ratio and comparison with threshold value obtained from HV data.

Results: Based on analysis of healthy individuals' data, the optimal threshold value for the left atrial patchy LGE quantification was determined at 1.38. Patients with AF had a higher extent of LA patchy LGE (9.1 [1.72; 18.58] %) than patients with hypertension (3.81 [0.57; 9.51] %) and HV (0.78 [0.05; 3.5] %). The predominant location of LA patchy LGE in AF was in the pulmonary vein ostia region, in hypertension - LA posterior wall, and in HV - lower part of LA posterior wall. In AF patients, the extent of LA patchy LGE correlated with LA end-diastolic volume (r=0.37) and LA ejection fraction (r=-0.4), in HV - with age (r=0.66) and LA end-diastolic volume (r=0.4).

Conclusion: AF and hypertension are associated with higher extent and different location of LA patchy LGE compared to changes caused by natural aging. The extent of LA patchy enhancement correlates with LA dilatation.