Atrial fibrillation can lead to which of the following complications in the atria?

Atrial fibrillation can lead to thrombus formation in the atria due to the disorganized electrical activity that disrupts normal atrial contraction. In atrial fibrillation, the atria do not contract effectively, which causes blood to pool within the atrial chambers, particularly in the left atrial appendage. This pooling increases the risk of clot development, or thrombus formation, because stagnant blood is more prone to clotting. If a thrombus forms in the atrium, it can dislodge and enter systemic circulation, potentially leading to serious complications such as a stroke.

In contrast, other complications like myocardial infarction, cardiac arrest, or bradycardia are less directly associated with atrial fibrillation. While these can occur in the setting of various cardiac conditions, they are not specific complications arising directly from atrial fibrillation itself in the same way that thrombus formation is. Understanding this link between atrial fibrillation and thrombus formation is crucial for managing patients with this dysrhythmia, especially in evaluating stroke risk and the need for anticoagulation therapy.