The impact of 6 weeks of atrial fibrillation on left atrial and ventricular structure and function

Abstract

Objective The impact of prolonged episodes of atrial fibrillation on atrial and ventricular function has been incompletely characterized. The purpose of this study was to investigate the influence of atrial fibrillation on left atrial and ventricular function in a rapid paced porcine model of atrial fibrillation. Methods A control group of pigs (group 1, n = 8) underwent left atrial and left ventricular conductance catheter studies and fibrosis analysis. A second group (group 2, n = 8) received a baseline cardiac magnetic resonance imaging to characterize left atrial and left ventricular function. The atria were rapidly paced into atrial fibrillation for 6 weeks followed by cardioversion and cardiac magnetic resonance imaging. Results After 6 weeks of atrial fibrillation, left atrial contractility defined by atrial end-systolic pressure-volume relationship slope was significantly lower in group 2 than in group 1 (1.1 ± 0.5 vs 1.7 ± 1.0; P = .041), whereas compliance from the end-diastolic pressure-volume relationship was unchanged (1.5 ± 0.9 vs 1.6 ± 1.3; P = .733). Compared with baseline, atrial fibrillation resulted in a significantly higher contribution of left atrial reservoir volume to stroke volume (32% vs 17%; P = .005) and lower left atrial booster pump volume contribution to stroke volume (19% vs 28%; P = .029). Atrial fibrillation also significantly increased maximum left atrial volume (206 ± 41 mL vs 90 ± 21 mL; P < .001). Left atrial fibrosis in group 2 was significantly higher than in group 1. Atrial fibrillation decreased left ventricular ejection fraction (29% ± 9% vs 58 ± 8%; P < .001), but left ventricular stroke volume was unchanged. Conclusions In a chronic model of atrial fibrillation, the left atrium demonstrated significant structural remodeling and decreased contractility. These data suggest that early intervention in patients with persistent atrial fibrillation might mitigate against adverse atrial and ventricular structural remodeling.

New-onset postoperative atrial fibrillation after aortic valve replacement: Effect on long-term survival

“…25,26 Striving for sinus rhythm as soon as possible when new-onset POAF occurs also is supported by a recent study that demonstrated that in a porcine model the left atrium underwent significant structural remodeling and decreased contractility after 6 weeks of AF. 27 Limitations A limitation of the present study is that we, because of its retrospective design, did not study patients with different treatment strategies on new-onset POAF. Therefore, we do not know whether the findings of the present study would still be valid in the event that new-onset POAF was treated in another way than in the present study.…”

Left atrial function after epicardial pulmonary vein isolation in patients with atrial fibrillation

“…As described previously [ 9 ], 76% had no symptomatic AF recurrences or AF episodes on 24-h Holter recordings at 12 months follow-up. The success rate is important since AF may cause significant structural remodeling and decreased contractility of the left atrium [ 22 ] promoting thromboembolism [ 23 ]. In our study, there were no thromboembolic events during 12 months follow-up except for in the one patient in whom an adequate anticoagulation medication had not been followed which emphasizes the importance of adequate anticoagulation throughout the procedure.…”

Evaluation of atrial remodeling in patients after maze procedure

“…Результаты после операции «Лабиринт» характеризуются восста-новлением синусового ритма, физиологическим проведением импульса по предсердиям, нали-чием предсердного вклада и ремоделированием предсердий (рис. 3) [13,[25][26][27].…”