How atrial fibrillation may affect your brain

This heart rhythm disorder is linked to thinking and memory problems. But anti-clotting drugs may lower the risk.

Bouts of atrial fibrillation, or afib — a rapid, chaotic heartbeat — make some people feel lightheaded and dizzy, while others don't notice any symptoms. But the most serious threat of this condition is the higher risk of stroke among people with afib compared with those without the disorder (see "Blood clot dangers, large and small"). Now, there's a growing recognition that people with afib also face an increased risk of thinking and memory problems — even if they do not experience a stroke.

Known as cognitive impairment, these problems include trouble remembering, learning new things, concentrating, or making routine decisions. The presumed underlying cause? Tiny blood clots that cause "silent" (that is, unrecognized) strokes and gradually injure parts of the brain involved with cognition.