Atrial fibrillation is caused by multiple electrical impulses that are initiated randomly from many ectopic sites in and around the atria, commonly near the roots of pulmonary veins.

房颤是由多个电脉冲引起的，这些电脉冲是从心房内和周围的许多异位部位随机发起的，通常在肺静脉根部附近。