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Question 6

In a few sentences, explain why atrial fibrillation greatly increases the risk of ischemic stroke.

Answer to Question 6

When the heart is in atrial fibrillation it does not eject blood effectively. This means that blood can pool and stagnate within the left atrium, greatly increasing the chance that a thrombus will form. A thrombus in the left atrium can break up, pass into the left ventricle, and from there enter the systemic circulation and travel anywhere in the body, including the brain. Such a cardiac embolus can occlude arteries, sometimes producing a TIA (if the occlusion is brief), but more commonly a stroke (if the occlusion lasts long enough to produce permanent brain injury).