Atrial fibrillation (AF) has become one of the most significant health problems worldwide, warranting urgent answers to currently pending questions on the effects of AF on brain function. Recent evidence has emerged to show an association between AF and an increased risk of developing dementia and worsening of stroke outcomes. A healthy brain is protected by the blood–brain barrier (BBB), which is formed by the endothelial cells that line cerebral capillaries. These endothelial cells are continuously exposed to shear stress (the frictional force generated by blood flow), which affects endothelial cell structure and function. Flow disturbances as experienced during AF can disrupt the BBB and leave the brain vulnerable to damage. Investigating the plausible mechanisms in detail, linking AF to cerebrovascular damage is difficult in humans, leading to paucity of available clinical data. Here, we discuss the available evidence for BBB disruption during AF due to altered cerebral blood flow, and how this may contribute to an increased risk of dementia and worsening of stroke outcomes.

心房颤动 (AF) 已成为全球最重要的健康问题之一，需要紧急回答目前关于 AF 对脑功能影响的悬而未决的问题。最近的证据表明，房颤与患痴呆症的风险增加和中风结局恶化之间存在关联。健康的大脑受到血脑屏障 (BBB) 的保护，血脑屏障由分布在大脑毛细血管内的内皮细胞形成。这些内皮细胞不断受到剪切应力（血流产生的摩擦力）的影响，从而影响内皮细胞的结构和功能。AF 期间经历的流动障碍会破坏 BBB 并使大脑容易受到损害。详细研究可能的机制，将 AF 与人类的脑血管损伤联系起来是困难的，导致缺乏可用的临床数据。在这里，我们讨论了由于脑血流改变导致 AF 期间 BBB 破坏的现有证据，以及这可能如何导致痴呆风险增加和中风结果恶化。