Abstract
Atrial fibrillation (AF) is associated with systemic thrombo-embolism and stroke events, which do not appear significantly reduced following successful pulmonary vein (PV) ablation. Prior studies supported that thrombus formation is associated with left atrial (LA) flow alterations, particularly flow stasis. Recently, time-resolved three-dimensional phase-contrast (4D-flow) showed the ability to quantify LA stasis. This study aims to demonstrate that LA stasis, derived from 4D-flow, is a useful biomarker of LA recovery in patients with AF. Our hypothesis is that LA recovery will be associated with a reduction in LA stasis. We recruited 148 subjects with paroxysmal AF (40 following 3–4 months PV ablation and 108 pre-PV ablation) and 24 controls (CTL). All subjects underwent a cardiac magnetic resonance imaging (MRI) exam, inclusive of 4D-flow. LA was isolated within the 4D-flow dataset to constrain stasis maps. Control mean LA stasis was lower than in the pre-ablation cohort (30 ± 12% vs. 47 ± 18%, p < 0.001). In addition, mean LA stasis was reduced in the post-ablation cohort compared with pre-ablation (36 ± 15% vs. 47 ± 18%, p = 0.002). This study demonstrated that 4D flow-derived LA stasis mapping is clinically relevant and revealed stasis changes in the LA body pre- and post-pulmonary vein ablation.
Highlights
Atrial fibrillation (AF) is the most common arrhythmia associated with high morbidity and thrombo-embolism mortality [1]
Previous studies have suggested that reduced flow velocity, i.e., flow stasis, in the left atria (LA) and left atrial (LA) appendage among subjects with paroxysmal AF in sinus rhythm can be an independent predictor of thrombus formation and stroke [3,4,5]
This study aims to demonstrate that LA stasis, derived from 4D-flow, is a useful biomarker of LA recovery in patients with AF undergoing pulmonary vein (PV) ablation
Summary
Atrial fibrillation (AF) is the most common arrhythmia associated with high morbidity and thrombo-embolism mortality [1]. Previous studies have suggested that reduced flow velocity, i.e., flow stasis, in the left atria (LA) and LA appendage among subjects with paroxysmal AF in sinus rhythm can be an independent predictor of thrombus formation and stroke [3,4,5]. The complex 3-dimensional nature of LA flow can be explored using four-dimensional flow (4D-flow) by magnetic resonance imaging (MRI), which has proved to effectively assess LA stasis [6,7,8]. In patients where rate control and anti-arrhythmic drugs are insufficient, pulmonary vein (PV) ablation therapy is used to maintain sinus rhythm. The assessment of LA stasis changes due to ablation therapy requires further exploration
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