Formation of low‐voltage zones on the anterior left atrial wall due to mechanical compression by the ascending aorta. (12th May 2021)

• Record Type: Journal Article
• Authors: Hayashida, Satoshi; Nagashima, Koichi; Kurokawa, Sayaka; Arai, Masaru; Watanabe, Ryuta; Wakamatsu, Yuji; Otsuka, Naoto; Yagyu, Seina; Iso, Kazuki; Okumura, Yasuo
• Is Part Of: Journal of cardiovascular electrophysiology. Volume 32:Number 8(2021)
• Page Start: 2275
• Page End: 2284
• Publication Date: 2021-05-12
• Subjects: ascending aorta -- atrial fibrillation -- extracardiac structures -- left atrial remodeling -- low‐voltage zones -- voltage mapping; Blood vessels -- Physiology -- Periodicals; Electrophysiology -- Periodicals; Heart -- Physiology -- Periodicals; 612.1
• DOI: 10.1111/jce.15076
• Languages: English
• ISSNs: 1045-3873

Abstract

Abstract: Background: Although low‐voltage zones (LVZs) in the left atrium (LA) are considered arrhythmogenic substrates in some patients with atrial fibrillation (AF), the pathophysiologic factors responsible for LVZ formations remain unclear. Objective: To elucidate the anatomical relationship between the LA and ascending aorta responsible for anterior LA wall remodeling. Methods: We assessed the relationship between existence of LVZs on the anterior LA wall and the three‐dimensional computed tomography image measurements in 102 patients who underwent AF ablation. Results: Twenty‐nine patients (28%) had LVZs grearer than 1.0 cm 2 on the LA wall in the LA‐ascending aorta contact area (LVZ group); no LVZs were seen in the other 73 patients (no‐LVZ group). The LVZ group (vs. no‐LVZ group) had a smaller aorta‐LA angle (21.0 ± 7.7° vs. 24.9 ± 7.1°, p = .015), greater aorta‐left‐ventricle (LV) angle (131.3 ± 8.8° vs. 126.0 ± 7.9°; p = .005), greater diameter of the noncoronary cusp (NCC; 20.4 ± 2.2 vs. 19.3 ± 2.5 mm; p = .036), thinner LA wall‐thickness adjacent to the NCC (2.3 ± 0.7 vs. 2.8 ± 0.8 mm; p = .006), and greater cardiothoracic ratio (percentage of the area in the thoracic area, 40.1 ± 7.1% vs. 35.4 ± 5.7%, p < .001). The aorta‐LA angle correlated positively with the patients' body mass index (BMI), and the aorta‐LV angle correlated negatively with the body weight and BMI. Conclusion: Deviation of the ascending aorta's course and distention of the NCC appear to be related to the development of LA anterior wall LVZs in the LA‐ascending aorta contact area. Mechanical pressure exerted by extracardiac structures on the LA along with the limited thoracic space may contribute to the development of LVZs associated with AF.