What is a major risk associated with atrial fibrillation?

A major risk associated with atrial fibrillation is thrombus formation and stroke. In atrial fibrillation, the normal rhythmic contractions of the atria are replaced by chaotic electrical activity, leading to ineffective pumping of blood. This can result in blood pooling in the atria, particularly the left atrial appendage, which significantly increases the risk of clot formation. If these clots dislodge, they can travel to the brain, resulting in an ischemic stroke.

This condition is particularly concerning because strokes related to atrial fibrillation can be more severe and disabling. The risk of stroke is influenced by multiple factors, including the patient's age and underlying health conditions, but the fundamental mechanism remains the potential for thrombus formation due to the stagnant blood flow in the fibrillating atria.

Other risks listed, such as hemorrhagic stroke or heart block, while relevant in the broader context of cardiac complications, do not directly reflect the primary concern in atrial fibrillation. Hemorrhagic strokes are typically associated with significantly elevated blood pressure or anticoagulation therapy, while heart block involves electrical conduction issues that are less related to the thrombotic risks inherent in atrial fibrillation.