What is the most common site of emboli formation in atrial fibrillation?

The most common site of emboli formation in atrial fibrillation is the left auricle, which is a small, pouch-like structure located on the left atrium. In atrial fibrillation, the chaotic electrical impulses lead to ineffective atrial contraction and loss of coordinated blood flow. This can result in stasis of blood, particularly in the left auricle where blood pooling is more likely to occur due to its morphology and anatomical position.

The left auricle is often a site for thrombus (blood clot) formation because it can be difficult for blood to flow properly in this region when atrial rhythm is irregular. The thrombus that forms here can dislodge and travel to systemic circulation, leading to serious complications such as an ischemic stroke.

Understanding this concept is crucial because it underscores the importance of anticoagulation therapy in patients with atrial fibrillation to prevent thromboembolism originating from the left auricle.