Heart-aorta-angle correlates left atrial low voltage areas formation in hypertensive atrial fibrillation patients.

Abstract

Background: The mechanism of low voltage areas (LVAs) formation in hypertensive atrial fibrillation (AF) patients is not clear. This observational study aimed to investigate the characteristics of atrial substrate in hypertensive AF patients and potential mechanism for abnormal LVAs formation related to heart-aorta-angle (HAA).

Methods: It was an observational cohort study. From June 2022 to September 2023, AF patients who underwent coronary computed tomography angiography (CCTA) and catheter ablation were included and assigned into hypertensive or normotensive group. The distribution of LVAs mapping in left atrium, CCTA measured HAA, and dimension of aortic sinus were brought into analysis.

Results: Forty-Eight of 93 patients (51.6%) (mean age, 62.63±10.01 years; 54 men) had long-standing hypertension. CCTA scan analysis showed hypertensive group (vs. normotensive group) had smaller ascending aorta-left atrium (AAo-LA) angle [mean ± standard deviation (SD), 29.11°±2.87° vs. 31.83°±2.04°, P<0.001], greater ascending aorta-left ventricular (AAo-LV) angle [median (interquartile range), 132.22° (129.80°-134.59°) vs. 129.33° (127.38°-131.87°), P<0.001], larger non-coronary cusp (NCC) diameter [20.80 (19.37, 21.71) vs. 19.11 (17.66, 19.69) mm, P<0.001], and larger NCC-commissure distance (34.85±2.57 vs. 33.54±2.14 mm, P=0.009). LVAs mapping results showed a larger total LVAs area in left atrium [19.11 (16.36, 20.13) vs. 15.63 (14.35, 18.04) cm2, P<0.001], especially in anterior wall (AW) in hypertensive group [5.11 (3.03, 5.75) vs. 3.42 (2.35, 4.42) cm2, P<0.001]. The AAo-LV angle (r=0.233, P=0.024), NCC diameter (r=0.324, P=0.002), and NCC-commissure distance (r=0.274, P=0.008) were positively related with AW-LVAs, and AAo-LA angle correlated negatively with AW-LVAs (r=-0.358, P<0.001). During a follow-up of 12 months, AF recurred in 16 patients (33.3%) in hypertensive group and in 7 patients (15.6%) in normotensive group (P=0.041).

Conclusions: In AF patients with hypertension, smaller AAo-LA angle is common. The closer AAo-LA interaction relationship may increase the mechanical contact, which relates to LVAs formation in left atrium and contribute to the atrial fibrosis in hypertensive AF patients.