Proximity to the descending aorta predicts regional fibrosis in the adjacent left atrial wall: aetiopathogenic and prognostic implications

Abstract

Aims Left atrial (LA) fibrosis is present in patients with atrial fibrillation (AF) and can be visualized by magnetic resonance imaging with late gadolinium enhancement (LGE-MRI). Previous studies have shown that LA fibrosis is not randomly distributed, being more frequent in the area adjacent to the descending aorta (DAo). The objective of this study is to analyse the relationship between fibrosis in the atrial area adjacent to the DAo and the distance to it, as well as the prognostic implications of this fibrosis. Methods and results Magnetic resonance imaging with late gadolinium enhancement was obtained in 108 patients before AF ablation to analyse the extent of LA fibrosis and the distance DAo-to-LA. A high-density electroanatomic map was performed in a subgroup of 16 patients to exclude the possibility of an MRI artifact. Recurrences after ablation were analysed at 1 year of follow-up. The extent of atrial fibrosis in the area adjacent to the DAo was inversely correlated with the distance DAo-to-LA (r = −0.34, P < 0.001). This area had the greatest intensity of LGE [image intensity ratio (IIR) 1.14 ± 0.15 vs. 0.99 ± 0.16; P < 0.001] and also the lowest voltage (1.07 ± 0.86 vs. 1.54 ± 1.07 mV; P < 0.001) and conduction velocity (0.65 ± 0.06 vs. 0.96 ± 0.57 mm/ms; P < 0.001). The extent of this regional fibrosis predicted recurrence after AF ablation [hazard ratio (HR) 1.02, 95% CI 1.01–1.03; P = 0.01], however total fibrosis did not (HR = 1.01, 95% CI 0.97–1.06, P = 0.54). Conclusions Atrial fibrosis was predominantly located in the area adjacent to the DAo, and increased with the proximity between the two structures. Furthermore, this regional fibrosis better predicted recurrence after AF ablation than total atrial fibrosis.

LGE-MRI for diagnosis of left atrial cardiomyopathy as identified in high-definition endocardial voltage and conduction velocity mapping

“…In contrast, both the Utah- and IIR>1.20 methods most frequently detect LGE at the left posterior LA adjacent to the descending aorta, which is consistent with previous reports [17, 24, 13]. Caixal et al demonstrated that the spatial proximity of posterior LA-wall to the descending aorta determines the degree of LGE in this region [24]. In a subset of 16 patients, these authors reported reduction of bipolar voltages and CV values in LGE-areas at left posterior LA.…”

Progressive and Simultaneous Right and Left Atrial Remodeling Uncovered by a Comprehensive Magnetic Resonance Assessment in Atrial Fibrillation

“… 17 Interestingly, the close anatomical relationship between these areas and the descending aorta has been recently claimed to potentially contribute to fibrosis accumulation by means of continuous and repetitive microtrauma. 28 Right atrial fibrosis localization had not been systematically assessed. By mean of rough visual inspection, Akoum and coworkers suggested that the most affected areas were the septum, superior and inferior peri‐cava veins and posterior venous wall.…”

Distance between the descending aorta and the left inferior pulmonary vein as a determinant of biophysical parameters during paroxysmal atrial fibrillation cryoablation

“…20 Recently, the extent of atrial fibrosis in this region was demonstrated to be inversely correlated with the distance between the DA and the LA. 21 Our study shows that blood flow even outside the atrium seems to Abbreviations: CI, confidence interval; DA, descending aorta; LIPV, left inferior pulmonary vein; TTI, time-to-isolation.…”