Cause & Risk Factors
The most serious consequence of atrial fibrillation (AF) is ischemic stroke. It is estimated that patients with AF are five times more likely to have a stroke.1 Therefore most AF patients—regardless of the severity of their symptoms or frequency of episodes—benefit from treatment to reduce the risk of stroke.
In patients with AF, blood tends to pool and form clots in an area of the heart called the left atrial appendage (LAA), a thin, sack-like appendix located in the upper left chamber of the heart. A blood clot that breaks loose from this area may migrate through the blood vessels and eventually plug a smaller vessel in the brain or heart resulting in a stroke or heart attack. In non-valvular AF, over 90% of stroke-causing clots that come from the heart are formed in the LAA.2